BCC Particle Illusion

Particle Lines

The “Lines” subgroup allows you to connect the particles with lines in various ways.

There are four different ways to connect particles with lines; they can be used independently or in combination:

“Connect to Emitter”: draws lines from the particles to the emitter’s reference point.

“Connect to Birth Position”: draws lines from the particles to the position they had when first created. For point emitters that are not moving this gives the same results as “Connect to Emitter”, but for moving emitters or all other emitter types this will look very different from “Connect to Emitter”.

“Connect Particles”: draws a line from a particle to the previous particle. Since the “previous particle” can possibly be quite a distance away from the current particle — with area emitters for instance — once “Connect Particles” is enabled, a “Max Line Length” parameter becomes visible:

Use this to limit the lines that are drawn when connecting particles. Only lines that are below this limit will be drawn.

If you have a case where turning on “Connect Particles” results in a wild tangle of lines, try decreasing the “Max Line Length” value.

The final line option is “Draw Trails”. When checked, lines will be drawn to each particle’s position at previous frames, tracing the particle’s motion path with a trail. There are a few options for line trails:

“Trail Length”: Determines how many previous positions are used.

“Trail Fade”: How much of the trail is faded out to 0 opacity. A value of “50” means that the fade starts at 50% of the trail length. Note that the fade won’t be smooth for very short trails.

“Trail Taper”: How much of the trail will taper to 0 width. A value of “50” means that the taper starts at 50% of the trail length. Note that the taper won’t be smooth for very short trails, and is more visible when using thicker lines.

The other line parameters relate to how the lines themselves look: their thickness, color, and opacity. They only become visible when one of the line options is enabled:

The “Intense” checkbox lets you make lines intense (additive) when the particles are not, or non-intense when the partices are. This can really help clarify some emitters by avoiding “wash out” with too many “intense” items.

Although the “Thickness” value can be set to any value between 0.0 and 100.0, you may find that only specific values make a visible difference when 2D lines are being used. This is entirely based on your hardware and or graphics driver — for instance a value of 0.5 might look exactly like a value of 0.9, then 1.0 will increase the visible thickness. Integer values should always work (we haven’t found a case yet where they don’t), so it’s probably best to stick to whole numbers when designing emitters using 2D lines.

Note that the antialiasing (smoothness) of lines may also be completely hardware or graphics driver dependent.

When using 3D lines (set in the Emitter Properties section), these limitations in thickness, antialiasing, etc. do not apply.

“Size Scales Thickness” adjusts the thickness of lines based on particle size. (Applies only when the “Size Variation” of the particle type is non-zero.) This works best with thicker lines.

For Line Color there are two options: “Use Particle Color”, which is self-explanatory, and “Specify”, which lets you set the color independently of the particles.  Note that even when you select “Specify”, if the emitter has a non-zero Tint Strength, the Tint Color will be applied to lines as well as particles.

Line Opacity also has two options: “Scale Particle Alpha” and “Specify”. If the particles have an alpha that changes over time, you may want to use “Scale Particle Alpha”, as the line opacity will be the result of the “Opacity” value (set here in the “Lines” section) multiplied by the current alpha of the particles. If you want the lines to fade out with the particles, use this option.

If instead you want to the lines to remain at a constant opacity regardless of what the particle alpha is doing, use the “Specify” option.  Note that with this setting lines will abruptly disappear when the particle dies.

There is one last option that shows only when using “Connect to Emitter” or “Connect to Birth Position”:

When “Lines Fade” is set to a positive value, the start of each line is faded. This can help avoid situations where you get the “starburst” of lines converging to a point.

When “Lines Fade” is set negative, the end point of each line is faded.

In this example, the left is Lines Fade = 0, middle is Lines Fade = 100, right is Lines Fade = -100:

Although the appearance of particle lines is often dependent upon your specific graphics hardware and/or driver (when using 2D lines), you’ll find that lines are an important addition to many particle creations!

Creative Tip: If you want lines only but don’t want to see the particles, set the particle “Size” value to 0.

Particle Turbulence

The final subgroup is the “Turbulence Field” group:

The parameters in this group allow you to adjust the noise field of each particle type individually.  Remember that the base Turbulence Field settings are made in the Emitter Properties, and by default each particle type in the emitter will use the same settings.

“Frequency Scale” is an additional multiplier to the base Frequency. Higher values result in higher frequencies (a smaller noise pattern in general).

“Offset” allows you to use a different portion of the turbulence field, giving these particles a different turbulence look without changing the frequency.

“Random Offset” gives a random offset amount to each individual particle. Large values result in chaotic noise that loses its organic feel, but smaller values can “smooth out” the turbulence pattern and soften the final look.

Changing Particle Shape Images (“Sprites”)

When you click the “Shape Image” thumbnail (or double-click the thumbnail on the particle node), the Shape Editor dialog opens:

This dialog lets you:

1. Select a new shape from those available in any of the available emitter libraries
2. Import a shape from an image file
3. Generate a new image using AI

1. Selecting from Available Sprites

As you select a shape from those available, the “New Shape” thumbnail will give you a larger preview of the selected shape, but more importantly the particles in the Stage are updated. (You can open the Shape Editor dialog while playback is occurring so it’s possible to see the particles in motion.)

The dialog opens with the shapes from the currently active emitter library, but you can select any other library on the left to choose from the shapes available there.

The right part of the Shape Editor displays useful information about the selected sprite/image, specifically:

• The total approximate memory footprint of the selected library (shown in the title bar)
• The approximate memory footprint of the selected shape
• The emitters that are using the selected shape (in the scrollable “Used in:” window)

If the “Used in:” window is blank, the selected shape is not used in the selected library.

Note that in the display grid of shapes, any unused shapes will have their name dimmed, so you can tell at a glance which shapes are not being used – which can be helpful when creating your own libraries if memory usage or library file size is a concern.

The “Shape:” area contains the “Import”, “Generate”, “Delete”, and “Rename” buttons.

The “Delete” button only enables when an editable library is selected (more on this in another section). The title bar of this dialog indicates not only the library name, but whether or not the library is locked, and the approximate memory usage of the library. 

The “Rename” button is again enabled only when an editable library is selected, and allows you to rename a shape that you’ve added.

2. Importing from Image File

The “Import” button is used to select an image file. Several image formats are supported: BMP, HEIC, HEIF, JPG, JPEG, JP2, PNG, TIF. After selecting the image file the Import Particle Shape dialog shows:

It looks like there is a lot going on here, but there are two main decisions you need to make: image size, and whether to create a “Greyscale” or “Full Color” sprite.

Image size is set by the “Scale Image to:” value. Although Particle Illusion will let you choose a larger size than the original image, you’ll get best results when using the same size or smaller – which is why the “Original Size” is indicated.

The intended use for the sprite is critical when determining the size. If the sprite will only be used by tiny particles like dust, sparks, or sparkles, then there’s no reason to select a larger size. If instead you will, or might, use the sprites for large particles like smoke, motion graphics elements, or anything similar, you’ll want to import large. Large sprites use much more memory, which is the main concern when selecting a size – it’s especially important when importing multiple frames.

If you’re importing for the current emitter only and this won’t be added to a library, the choice is less important, but unecessarily large textures will bloat your project size – including your host project size if running as a plugin, and could use more memory than it needs to.

The guidelines that we use when creating emitters for release (in a library):

• Use 256x256 for anything that will mainly be used at a small size
• Use 1024x1024 if the sprite will be shown very large – but only if one (or a few) frame(s)
• Use 512x512 as a compromise for medium/larger sprites or multiple frames

Since you have the original images, you can try importing at different sizes and see how it works in your project. It’s not really possible to have a sprite that is “too big” since it will be scaled down cleanly (especially if MIP mapping is used) – as long as memory is not a concern, but there is an obvious visual artifact if the sprites are too small for their current use: they will look very soft or blurred, with lack of detail and possibly visible pixelization.

The second choice you’ll need to make when importing is whether it will be a “Greyscale” sprite, or “Full Color”. What’s the difference? How do you choose?

Greyscale sprites are 8-bit, single channel, so hold no color information. An alpha channel is generated from the grey values: white pixels are fully opaque, black pixels are fully transparent. If you don’t need the sprite’s original colors, then “Greyscale” is the best choice. It’s especially good for smoke, sparkles, or similar. (Basically, use this unless you really need to retain the sprite original colors.)

Full Color sprites are 32-bit RGBA. Note that these sprites do not always show particle gradient colors or emitter tint colors accurately (tinting a green leaf sprite red for instance probably won’t give you a red leaf). Note that particles that use Full Color sprites but are flagged as “intense” actually use a Greyscale version of the sprite – the color information isn’t used. (This means a sprite imported as “Full Color” actually use 4 or 5 times the memory of the equivalent sprite imported as “Greyscale”.)

Remember that the approximate memory used by a sprite after importing shows below the preview in the upper left of the Particle Shape Editor – you can use this to verify that the sprite you’ve imported has reasonable memory usage. (Usually on modern machines and OSes, this is not a huge concern. It’s worth checking into if you start seeing memory-related issues though.)

After selecting the size and type of sprite, there are a few details like naming the shape/sprite and selecting where the sprite should be used. If the current emitter library is one that can be edited (is unlocked), then you’ll be able to choose between importing this shape into the library, or just applying it to the current emitter. If the library is locked you’ll only be able to import to the current emitter.

Note that both here and in the Particle Shape Editor the transparency of the sprites can be shown via checkerboard in all of the large previews. You can click the preview itself to toggle the transparency on and off — or here you can use the “Show Alpha” checkbox.

Importing a Sequence

If you want to import a sequence of images to use for the particle sprites rather than a single image, the files must be named as a sequence with a number at the end.  For instance, “blur_round_00.jpg”, “blur_round_01.jpg”, “blur_round_02.jpg”, etc. If Particle Illusion detects that the selected image is part of a sequence, it will allow you to import the sequence instead:

When the sprite contains multiple frames, you can use the arrow keys below the preview to switch frames, or you can just scroll when your mouse cursor is over the image (using your mousewheel or trackpad scroll gesture).

Note: if you uncheck the “Import Shape Sequence” option when a sequence is detected, only the first image of the sequence will be used – NOT the exact image you selected.

Full Color: Creating Alpha

As mentioned earlier, Greyscale sprites always create an alpha channel. It’s also possible to create alpha for Full Color sprites using one of two options:

“Alpha from Luma”: Uses the luma values for alpha. The “Scale Lights” slider can be used to make light areas less transparent, and “Crush Blacks” will make near-black pixels darker.

“Remove Background”: If the image has a black background this option will remove it but can also preserve interior dark details in the image itself. (“Alpha from Luma” will make those dark interior details transparent). Use “Crush Blacks” for more control.

Clean Black Background

In order to have a sprite with no “border edges” showing, you’ll want to ensure that the alpha is 0 at the edges, and if you’re creating the alpha from the image here that means the background must be completely black (RGB 0,0,0) at the edges. The “Highlight Black” option below the preview will help with this:

When checked, “Highlight Black” makes all of the fully black (RGB 0,0,0) pixels bright green so that it’s obvious when the edges of your image are not black.

Use the “Crush Blacks” control to clean up any noise in the background too.

3. Generate Using AI

The third function of the Particle Shape Editor allows you actually generate (create) new sprites using Stability.AI’s Stable Diffusion.

Click the “Generate” button to open the Generate Particle Shape dialog:

The first time you open this, you’ll be guided through a couple of setup steps. The red text indicates that you need to enter an “API Key”.

Sprite generation in Particle Illusion uses Stable Diffusion, which requires a third-party Stability.ai account (not affiliated with Boris FX in any way). You need “credits” to use this feature, and creating your Stability.ai account gives you a small number of them for free, or you can purchase additional credits - they are not expensive.

Your Stability.ai account page will show your API Key(s) - copy one and then paste it here and click the “Acct Info” button as indicated:

You should see the account information update with your email address, user ID, and credit balance.

Check the “Save API Key in Prefs” option if you want it to be automatically entered for you each time. Note that it stored in your preferences unencrypted, but it is a simple thing to invalidate your API Key at your DreamStudio account page and create a new one if you ever think that’s necessary.

How Sprite Generation Works

Generative AI typically relies on text prompts that describe the result you’d like, with other settings to determine how accurate the results need to be, what artistic style to use, etc. In Particle Illusion you always start with an existing sprite – a “seed image” – that is used as a starting point for the Stable Diffusion generator. This “seed image” makes it much easier to get the results you want in a format that is useful as a sprite – most notably the black background.

When the Generate Particle Shape dialog opens, whatever sprite was currently selected is used for the “seed image”. If you don’t select a sprite before opening this, the first sprite of the current library will be used.

We’ll detail each of the different parameters shortly, but an easier way to jump into this is to click the “Load” button in the “Presets” area, which opens the Particle Shape Generation Presets dialog:

In this example we selected and applied the “Cartoon Grass, Detailed” preset. Loading a preset updates all of the settings, including the seed image. You’ll notice that there is already a “Generated Image” shown even though we haven’t actually generated anything – that’s the preset thumbnail image:

When you click the “Generate” button, Particle Illusion will send the image request to the servers and wait for the images to be returned:

This can take anywhere from 3 to 30 seconds (or more) depending on the settings, number of images to generate, connection speed, server load, etc.

If the “Generating Images…” prompt stays for a minute or more – whenever you’re certain that something is not right – you can manually close this window using the “X” button in the window title bar and try again.

When the images are received from the server, the window is re-enabled and your results are displayed:

You can now select any of the resultant images and click the “Import” button to close this window and start the sprite import process, which works exactly the same as if you were importing from an image file (see above).

If you’re not happy with the results, you can change any of the settings (like “Seed”) and click “Generate” again to get a new set of images. Note that if you don’t change any setting and just click “Generate” again, you should get back identical (or very nearly so) results, but the order of the returned images will probably have changed.

Experiment Without Fear

Even if you decide that generating a sprite isn’t what you want at this time, just click the “Close” button to get back to the Particle Shape Editor button. The next time you open the Generate Particle Shape dialog you’ll resume almost exactly where you left off – you won’t have lost anything.

I say “almost” exactly where you left off because the seed image will have updated to whatever was selected when you opened this dialog – that’s the desired workflow so you can quickly try different sprites for seed images.

If you really do want to use every one of the settings you had previously, including the seed image, the History keeps all of your previous generate results, including a scaled version of the resultant images:

Select any history item and all of its settings are restored, including the generated images. The images stored in the History will probably be smaller than freshly-generated images, but may still be a useful size-as is.

Set the size of images in the History in the History Options:

The larger the history images are, and the greater the number kept, the larger the history file will get – and the longer it will take to save it whenever it changes. (It only saves upon close of the Generate Particle Shape dialog).

As indicated in the History Options dialog, changing the image size will only change hitory items saved after the change – it does not resize all previous images.

If you rarely use history images directly for importing, you may want to set the history image size to 256 or 128 – that will greatly reduce the size of the history file.

Sprite Generation Settings

Let’s take a look at each of the settings for image generation:

Each of these displays a tooltip when hovered over, but here’s more detail on each.

Image Strength: How closely the seed image should be followed. When set to 0, ignored the image completely (not recommended). Values around 0.10 - 0.15 are usually good starting points.

Steps: How many “diffusion steps” to run – essentially “iterations”. Higher values use more credits and may result in more realism or details, which is not always desirable for sprites.

Prompt Strength: How closely the Prompt is followed. Values around 20-25 seem good.

Seed: The random noise seed. Must be non-zero if you want to save a preset.

Size: The size of the generated image. Don’t change this unless you get an error message saying that you need to (after you change model).

Model: The engine to use. You’ll probably never change this, but note that this list may change in future updates as new engines become available.

Prompt: The text that describes what you want to generate. This is required. It’s best to keep this relatively simple, but remember that it won’t understand everything. (For instance, try to get it to generate a single piece of popcorn. Good luck!) The “weight” determines how strongly to follow these.

Negative Prompt: The description of things you don’t want to see. Best to leave this empty and only add things as they show up in your results. For instance, you can use this to try and keep a “shadow” or “stem” out of the generated images. The “weight” determines how strongly to follow these – set to “0.00” to ignore the Negative Prompt.

Num Images: How many images to generate. You may want to keep this low when experimenting, but a single image may give misleading results – it may be the one “bad” image of the current settings. If you generate more than 4 images, the Generated Images window can be scrolled (even though there is no visible scroll bar).

Style: The artistic style to apply when generating. Typically you’ll want to keep this as “none”, although some of the styles are quite interesting, and it’s fun to experiment.

Here’s the leaf example from one of the Sprite Generation Presets set to various styles. In each case all other settings were the same – only the “Style” changed. (The returned images are not always in the same order.)

Style: “None”

Style: “Photographic”

Style: “Line-Art”

Style: “Anime”

Style: “Fantasy-Art”

Style: “3D-Model”

Style: “Low-Poly”

Style: “Modeling Compound”

Style: “Origami”

Style: “Pixel-Art”

Some Styles will add unwanted effects (not useful for sprites), for instance “Cinematic” seems to always want to simulate a short depth of focus, resulting in blurring parts of the image – even if it doesn’t make sense.

If you’re having a hard time getting rid of some stylistic feature and the Style is not set to “None”, try changing it to that to see if it helps.

The ability to generate sprites (added in the 2024.0 version of Particle Illusion) is a huge leap forward in creativity and utility.

Reference Point

The “Reference Point” for a particle is the point at which scaling and rotation happens. Most of the time this reference point is set to the center of the particle shape/sprite, but it’s often useful to move that reference point — you can do this by clicking the red circle “Reference Point” icon in particle properties:

The resulting dialog lets you click and position the reference point wherever you want:

When you click to update the point position, you’ll see a faint indicator of the original position. Also the Stage will update as you make changes to the reference point, allowing you to see the results of any changes to the particles in your project.

Zoom the window by scrolling — zooming out is the only way to set the reference point farther away from the center.

You can set the reference point to the center of the image using the “Center” button.

One note about particle lines with an off-center reference point: lines always draw to the reference point, so will appear offset or “detached” from the sprite. The only way to avoid this is to reset the particle reference point back to the center.

Emitter Shapes

In the emitter properties group you can select different “shapes” for the emitter, and depending on the shape chosen there are additional parameters that are revealed. The options in 2D projects are “Point”, “Line”, “Ellipse”, “Area” and “Circle”. In 3D projects they are expanded: “Point”, “Line”, “Ellipse”, “Plane”, “Circle”, “Box”, “Sphere”, and “3D Model”.

For “Point” emitters, the particles all emanate from a single point. This is the simplest shape for an emitter, and there are no additional parameters for it.

With “Line” emitters, the particles all emanate from a line or series of connected line segments. After switching the shape to “Line” you will see a line (if the HUD is enabled) from the emitter point to the mouse position. Clicking adds a new line point — double-click or press the ESC key to end the line. Line emitters have the following additional parameters:

• Emission In: particles will be emitted from one side of the line. Note that only when Emission Range is set below 360 degrees will you see this, and it will be most clear when the Emission Range is below 180 degrees.
• Emission Out: particles will be emitted from the other side of the line.
• Emit at Points: When checked the “Number Points” parameter becomes visible. Use this option to create a row of point emitters evenly spaced along the line (or line segments).

Note that on Mac Cmd-click will delete a line emitter point, and Option-click will allow you to add points to the line. On Windows Ctrl-click to delete a line point, and Alt-click to add them.

Set to “Ellipse”, the particles will be created along the ellipse. As with “Line” emitters, these additional parameters are available:

• Emission In: particles will be emitted toward the inside of the ellipse. Note that only when Emission Range is set below 360 degrees will you see this, and it will be most clear when the Emission Range is below 180 degrees.
• Emission Out: particles will be emitted toward the outside of the ellipse.
• Emit at Points: When checked the “Number Points” parameter becomes visible. Use this option to create evenly spaced point emitters along the ellipse.

In addition, “Ellipse” emitters have “X Radius” and “Y Radius” parameters which can be used to resize the ellipse.

Unlike the other shapes, “Area” emitters create particles throughout a rectangular area (not just along the outline). In 3D projects “Area” is called “Plane”, but it behaves the same. Area/Plane emitters add:

• Emit at Points: When checked the “Num Points X” and “Num Points Y” controls are revealed, allowing you to create a grid of point emitters.
• “Width” and “Height” parameters to control the dimensions of the rectangle.

A “Circle” emitter is a special case of “Ellipse”, in that only a single “Radius” parameter is added instead of “Radius X” and “Radius Y” — all other parameters for “Circle” emitters are the same as for “Ellipse” emitters.

“Box” and “Sphere” emitters are 3D analogs of the 2D “Area” and “Circle” shapes. Box emitters create particles throughout their volume (in the same way that “Area” emitters create points throughout the rectangle area), while “Sphere” emitters create particles along their surface (in the same way that “Circle” emitters create particles along the circumference).

Box emitters add a “Depth” parameter to complement “Height” and “Width”, and when “emit at points” is checked a “Number points Z” parameter is added.

One important note about emitter shapes other than “Point”: Line, Ellipse, Circle, and Area emitters can emit more particles the “bigger” the shape. The “Scale Number with Shape” controls this:

For instance, with this parameter checked a long line emitter will create many more particles than a short line emitter, a circle emitter with a large radius will create many more particles than a small radius, etc. The most extreme case of this is probably the “Area” emitters in 2D, and “Box” emitters in 3D — increasing the width and height of an area emitter so it fills the entire frame will most likely create many more particles than you intended, with the result of this being poor performance and greatly reduced responsiveness. 

For this reason it’s a good idea to uncheck “Scale Number with Size” if you’ll be increasing the dimensions of a shaped emitter.

Alternately, reduce the “Number” value significantly before increasing the dimensions (line length, radius, width and/or height) of any shaped emitter, then increase it again slightly afterward if necessary. This will ensure that performance and responsiveness stays optimal.

If you change an emitter shape and you don’t see the stage update right away, you may want to immediately uncheck “Scale Number with Size” or decrease the “Number” parameter to something very small — you don’t have to wait until the stage updates.

3D Models

When the “3D Model” emitter shape is selected, a file dialog immediately shows to allow you to choose the 3D model file to use for the emitter. Both C4D and OBJ file formats are supported by Particle Illusion.

After selecting a model file, the parameters specific to 3D models are displayed:

“Model File”: shows the filename of the current 3D model. Click to select a new model. (The tooltip for this parameter shows the full path to the current file.)

“Emit From”: Select what part of the model to use for emission: “Vertices”, “Edges”, “Surface”, or “Normal”

“Threshold Angle”: Only visible when emitting from “Vertices” or “Edges”. This sets the threshold angle for emission. For instance when set to “Edges” using a cylinder model, a threshold angle of less than 12 degrees will result in emission from most (or all edges):

While a threshold angle of more than 12 but less than 90 degrees will result in emission from the sharp edges only (the ends of the cylinder):

“Subdivide Large Polys”. This parameter is visible only with “Surface” emission, and is used to help distribute particle creation more evenly when your model contains a mix of large and small faces. When unchecked the smaller faces will have a higher particle density.

“Model Scale”: Scales the 3D model uniformly in all dimensions. (Note that upon import the 3D model scale is normalized to fit the frame – there is no way to turn that off. “Model Scale” is applied on top of that internal normalization.

“Model Scale X/Y/Z”: Used to scale the model along a specific axis.

“Use Model Color for Tint”: When checked, the color information stored in the model will be used instead of the “Tint Color”, and will be mixed with the selected wireframe color using the “Tint Strength” value.

“Show Wireframe”: Displays a wireframe of the model.

When “Show Wireframe” is checked, wireframe properties are shown:

Use these to set the wireframe opacity, color, and line thickness. The wireframe is very similar to the particle “lines” feature, except that Emitter “Tint Color” does not affect the wireframe.

Although the Wireframe Thickness value can be set to any value between 0.0 and 20.0, you may find that only specific values make a visible difference. This is entirely based on your hardware and or graphics driver — for instance a value of 0.5 might look exactly like a value of 0.9, then 1.0 will increase the visible thickness. Integer values should always work (we haven’t found a case yet where they don’t), so it’s probably best to stick to whole numbers.

Model Colors/Textures

When the 3D model uses colors, we’ve already seen that “Use Model Color for Tint” allows you to use those colors with “Tint Strength”.

If the model contains textures, “Use Model Color for Tint” pulls the colors from the texture instead of the model color. This can produce some complex effects:

Note that C4D models contain texture data, but OBJ models have textures as separate files. The texture file needs to reside in the same folder as the OBJ model. Also, when adding an emitter (or saving a scene) that contains an OBJ 3D Model, the model is copied to the PI3DModels folder, but the texture file is not – it must be copied manually.

Once an object is rotated, you can use the translate widget to move it along its own coordinate system, or instead along the world (screen) coordinates, depending on the state of the “World Coords” button. With “World Coords” off, the widget is aligned to the object’s rotated coords:

Remember that when widgets are not displayed, you can always click and drag an emitter to position it in the current view – widgets just give you more control when you need it.

Working with Data Keys

We mentioned already that it’s possible to click and drag a data key in the Graph View, and that you can change a data key’s value using the Controls View. There are a few other features that make working with data keys easier:

• Multi-selecting data keys. You can shift-click on keys in the graph view to select multiples, or click and drag to create a selection rectangle that will select multiple keys. All selected keys can be dragged as a group.
• Deleting data keys. Use your keyboard “delete” key to delete all selected keys.

When a data key is set to “Bezier” interpolation, you can drag the control handles to change the curve. In addition, you can:

• On Mac: Option-drag a bezier handle disconnects the two handles and lets them move independently. Option-drag on one of the disconnected handles to reconnect them.
• On Windows: Alt-drag a bezier handle disconnects the two handles and lets them move independently. Alt-drag on one of the disconnected handles to reconnect them.

Note that disconnected Bezier handles in the Graph View show in color:

Using the Playback Controls

The playback controls appear above the Graph View and below the Stage:

These allow you to toggle playback, move one frame forward/back, move 10 frames forward/back, or jump to the start frame (frame 0) or end frame. The spacebar is a keyboard shortcut for the play button.

There is also a “looping” control at the far right that should be self-explanatory.

The current frame number is shown to the left of the playback controls, and the length of the project in frames is shown to the right.

Note that you can click the number of frames as a shortcut to open up the Project Settings dialog.

The Mini Timeline

The area just above the playback buttons — where the blue frame indicator line shows — is called the “Mini Timeline”. You can click anywhere in the Mini Timeline to jump the current time indicator (CTI) to that frame.

This is also where keys are shown for the selected parameter — if you want to change the position of any keyframes you can do that in the Mini Timeline. Doing it here removes the risk that you might unintentionally change a keys value when trying to move it in the Graph View.

In and Out Points

Just above the Mini Timeline are the trim controls for setting the In and Out points. Drag them to set the playback range, or double-click between them to clear both of them and reset to the full play range.

For those who want more precise control over the In/Out controls, you can “nudge” these one frame at a time: hover the mouse cursor over the control, then use the L/R arrow keys to nudge. (Once the cursor moves off the In/Out marker, the arrow keys stop working.)

You can click in the play range (the area between In and Out) and drag to reposition In and Out together.

To jump the Out point in 1-second steps, position the cursor over the play range and use the mouse wheel or scroll gesture.

Note that start/end frame controls have dual usage: click the start frame button once to move to frame 0, then click it again to move to the “in” frame. Similarly the end frame control jumps to the last frame in the project, then to the “out” frame.

Jump by Five

When working in the mini timeline, it’s possible to jump the frame number to the nearest multiple of 5. When dragging the CTI, the In point, or Out point, just hold the Shift key.

Cache Indicator

You will have noticed that in the mini timeline there is a cyan line that draws from frame 1 to the CTI. This is the cache indicator. Particle Illusion will cache particle calculations which allows for better performance when scrubbing the timeline (under many circumstances). Note that it is not an image cache, so for projects with a large number of particles you may still not get smooth scrubbing.

If you ever notice something strange happening during playback — particles that glitch or jump for instance — you should reset the cache. An easy way to do this is to just select any parameter value and change it slightly, or even just click on it as if you were to type a new value but just hit Enter/Return to keep the same value. Once the cache recalculates the glitch should no longer occur.

Emitter Start Frame 

Below the playback controls is the Start Frame slider for the selected emitter:

By default added emitters are placed so that they start at the current frame. To make the emitter start at a different frame, just slide the head of this Start Frame slider by clicking and dragging it. Note that all data keys contained in this emitter will move with the slider — this is most important for emitters that have significant animation or turn off, such as explosion emitters.

Tip: the Start Frame also responds to the Shift key modifier to jump by five frames.

Note that if for some reason you don’t want the data keys to move with the slider you can CMD+click and drag on the slider head (on Windows CTRL+click and drag). This could be useful if, for instance, you want an explosion emitter to create particles for a bit longer before turning off. Instead of moving all of the “number” data keys to a later time (to the right) — and there could be several different “number” parameters where you’d have to do this — you can instead CMD-drag the Start Frame slider to an earlier time (to the left). 

The Start Frame slider shows a pale red negative number for some emitters (see image above). This is a reminder that the emitter has a non-zero value for the “Frames to Preload” parameter. Clicking the number on the Start Frame slider will highlight the parameter in the Controls View.

Emitter Libraries

Particle Illusion is preset driven, and there are well over 2500 particle emitters in the various emitter libraries. Only three libraries — the locked “Sampler” library, the locked library for this release (for instance “Emitters_2024.0”) and the editable “Custom” library — are installed with Particle Illusion. To get the additional libraries use the link provided in the “Help” menu:

You’ll need to restart Particle Illusion after installing those libraries to make them available.

If you see a red warning icon above the library browser…

…this is another indication that you don’t have all of the emitter libraries. Hover the mouse cursor over this icon for more information.

The concept of libraries is not so important in Particle Illusion because of the search function, but libraries do provide some level of organization. The important thing to know is that the legacy emitters have been grouped into themed libraries, so that most smoke emitters are in the “Smoke” library, explosions are in “Explosions”, etc. (The newest emitters are released in versioned libraries: “Emitters_2021.5” for instance.)

This is only important if you’re manually browsing the libraries, but with so many emitters to look at the only realistic way to browse is to first use the emitter search function.

Library Scenes

Starting with Particle Illusion 2022, libraries can now contain “Scenes” along with emitters. Scenes are similar to emitters in a library in that they both are a type of preset, both have thumbnail images, and both are added to the project in the same way. There are significant differences though:

• Scenes have a “+” symbol before their name
• Scenes only show their thumbnail image in the preview — it is not a live preview
• Scenes can contain multiple emitters, forces, and deflectors. (It is this complexity that requires the removal of the live preview)
• Scenes preserve position data, so are always added at absolute positions (you can’t click to add a Scene at a different position in the Stage)

Emitter Search

The emitter search can really help you reduce the number of emitters that you need to browse, and is the best way to quickly find what you’re looking for without a huge amount of scrolling. 

To search the emitter libraries, just start typing in the Search box below the preview.

The emitter search works over emitter names and on the tags saved with each emitter, and optionally on the folder/group names (which are only visible in List View).

Note that search works on Scenes as well as emitters.

In the Preferences for Particle Illusion there are a few options related to emitter searching:

• Search Folder Names: the folders in each emitter library are included in search results. When this option is checked all emitters in that folder will be included in the results if the search term is in the folder name. (This is not usually desired so is unchecked by default.)
• Search Tags: If you want to search only on emitter names you can uncheck this option. (It is checked by default as there are many emitters with names that are not descriptive.)
• Display Tags in emitter library: when checked, each emitter’s tags will display after its name in Library View. (The tags will not show in List or Grid views)

Here’s a list of all emitter search tags used in the emitter libraries:

Knowing these can help you search more effectively.

Note that tags can be combined, so searching for “sparkles red” will return all emitters tagged with both “red” and “sparkles”. 

Also note that new emitters are included with most major releases.  For instance, the new emitters in the Continuum 2023.5 release are in the library “Emitters_2023.5” — you can easily find these using the search tag “2023.5”.

Tip: It’s easy to isolate the library Scenes using search: just search on the “Scene” tag.

Locked vs. Unlocked Libraries

All libraries installed by either Particle Illusion or the Additional Emitter Libraries installer will be “locked” and can’t be edited with one exception: the “Custom” library. This is provided as a place to store your own emitters — it contains just a single very basic (not useful) emitter because emitter libraries can’t be empty.

The locked vs. unlocked status of an emitter library is determined by where the library file resides: there is one folder for “locked” libraries, and one folder for editable libraries. You can manually move or copy emitters from one folder to another as necessary. It is recommended that the emitter libraries released by Boris FX remain locked.

Locked emitter libraries are found in the following folder:

Mac:
/Library/Application Support/BorisFX/EmitterLibraries

Windows:   
C:\ProgramData\BorisFX\EmitterLibraries

The unlocked (editable) emitter libraries are found in the following folder:

Mac:   
/Library/Application Support/BorisFX/UserEmitterLibraries

Windows:    
C:\ProgramData\BorisFX\UserEmitterLibraries

Note that if you used (or are still using) the legacy version of particleIllusion 3.0 and created emitter libraries with it, those libraries can still be used in Particle Illusion. There is no “Load Library” command, so in order for Particle Illusion to find your emitter libraries you’ll need to copy them to one of those folders.

The more emitter libraries that are in those folders, the longer PI will take to load all of them, so you may want to be selective when you’re adding emitter libraries. Note that if you just copy all of the legacy pI3 emitter libraries for use in PI, you will have over 2500 duplicates — we curated the legacy pI3 libraries to create the PI libraries.

Adding an Emitter to a Library

Any emitter in your project can be added to one of the editable libraries. To do this, click the “hamburger” menu button to the right of the emitter in the controls view (or r-click the emitter node), then select “Save to Emitter Library…”

The “Save to Emitter Library” dialog then opens….

…and lets you rename the emitter, edit the emitter tags, and then choose the destination library (if more than one unlocked library exists).

As the dialog message indicates, there is no undo of adding an emitter to a library.

Adding a Scene to a Library

When you add an emitter to the library since it’s a single object you do it from the emitter’s “hamburger”/context menu. Since a scene contains everything in your project, you use the “File” menu to add it to a library:

Think of it as being similar to saving the project, but you’re saving it in the library instead of a project file.

Note that a Scene is not exactly the same as a project, as the following information that is saved in a project is NOT saved in library Scenes:

• Motion Blur settings
• Stage size (resolution)
• Camera data
• Layer data (position, rotation, etc.)
• Node layout

When you add a scene to a library, the exact contents of the Stage are used for the Scene thumbnail (cropped to a square), so you should make sure you move the CTI to a frame that is representative of the Scene. (Unlike with Library Emitters, It’s not possible to update the Scene thumbnail after it is added.)

Deleting Emitters/Scenes from a Library

To delete an emitter or Scene from a library, select the emitter/Scene then hit the key. If the selected item is in an editable library, you’ll get a confirmation dialog:

If the selected emitter/Scene is in a locked library, you will see an error message instead.

Emitter “Hamburger Menu”

Besides saving an emitter to a library, using the emitter “hamburger menu” you can also:

• Disable an emitter, which removes it from displaying and rendering.
• Solo the emitter
• Delete the emitter
• Duplicate it, making an exact copy of it
• Move it Up or Down in the layer (if more than one emitter exists) to change the render order in 2D projects only (Does not change render order in 3D projects)

Note that the Hamburger Menu is exactly the same as the context menu shown when R-clicking a node in the Nodes View.

Renaming Library Emitters/Scenes

You can easily rename an emitter/Scene or modify its tags in any unlocked library. Simply select the emitter/Scene then hit the Enter/Return key, and the rename dialog will appear.

You cannot modify emitters or Scenes that are in locked libraries. See the section on Locked vs. Unlocked Libraries above.

Adding/Removing Particle Types and Free Emitter Types

We’ve discussed all of the parameter changes you can make to a particle type (and to a free emitter type for super emitters), but we have not talked about how you can create a new particle type, or delete an existing one from an emitter.

Once a regular emitter is added to your project, you can create a new “basic” particle type using the “Add New Particle Type” option in the hamburger/context menu:

This will create a generic particle type using the first particle shape image from this current emitter, default parameters, and solid white for color gradient and alpha. You’ll need to customize everything in order to make it do anything interesting.

If instead you would like to make a copy of an existing particle type in this emitter — which may make setting the various parameters much easier — use the hamburger/context menu for that particle type (instead of for the emitter) and select “Duplicate Particle Type”:

Note that it’s also possible to Rename, Solo and Hide using this menu, as well as Delete and rearrange particle types (Move Up/Down) if the emitter contains more than one particle type. Note: Move Up/Down is only available in 2D projects, and is not overly useful for particle types.

Super emitters work similarly in that you can create a new “basic” free emitter type using the “Add New Free Emitter Type” menu (it may show as “Add New Emitter Type” in some versions), and can duplicate an existing free emitter type, delete free emitter types, hide them, etc.

Note that the order of particle types and free emitter types usually does not make much difference, but there can be some rendering differences in some cases.

Make Super Emitter

To convert a regular emitter into a super emitter, use the emitter hamburger/context menu “Make Super Emitter” function:

If your project contains a super emitter, you can add a regular emitter to that super emitter using the “Add to Super Emitter…” menu item:

Note that option is only available if there is a super emitter in the project, and displays only for regular emitters.

A dialog showing all available super emitters will show:

Note that the Free Emitter Type added to the super emitter will have the same name as the emitter that you added, and the original emitter will still be present in the project.

Note that there is no way to extract a regular emitter from a super emitter.

Creating An Emitter from Scratch

One of the advantages of Particle Illusion is its huge preset library. It’s much easier to start with a preset and then modify it to make it your own than it is to create one from nothing, but there are times when you might want to create an emitter without using a preset.

Technically this is not possible, as there’s no concept of an “empty” emitter in Particle Illusion, but starting with the 2021.0 version, some “Basic” emitters have been included that allow you to start from a nearly empty emitter.

If you do an emitter search for the word “Basic”, you’ll see a small collection of “Basic” emitters shown in the “Emitters_2021.0” library:

These five emitters are as close to a blank slate as you can get in Particle Illusion, and will let you create a custom emitter from scratch.

(Note that these are also included in your “Custom” emitter library – if you haven’t deleted them.)

Composite View (“Stage”) Controls

The Composite View or “Stage” is pretty straightforward, but there are some controls in the upper left corner of this view that require some explanation:

From left to right…

Presets: An easy way to show/hide the Emitter Libraries view and Preview.

Zoom: Sets the zoom level for the Composite View.

Preview Background: Select compositing over Black, checkerboard (which shows transparency), Source Frame, or Source Video. Note that the options in this list are ordered by performance, with fastest at the top and slowest at the bottom. (Source Frame and Source Video are only available in the plugin version.)

View Selector: Enabled only in 3D projects, and lets you switch between the Render (camera) view, Top, Left, Right, Bottom, and World Views — essential when trying to position objects in 3D space.

2D/3D: This allows you to switch between 2D and 3D modes.

Motion Blur: toggles motion blur for the Composite View. Performance is increased with motion blur off. (Note that the motion blur settings are in the Project Settings dialog covered later).

H.U.D.: Toggles the “heads up display”. When turned on, the overlays for object, position path, etc. are visible. When off only the particles are visible. Also note that the ground plane in 3D views is controlled by this button.

Translate Mode: For moving objects in the Stage with widgets.

Rotate Mode: For rotating objects with widgets.

Scale Mode: For scaling some objects with widgets.

World Coords: Toggles between Object and World coords when translating rotated objects.

+ Deflector: Used to add a deflector object to the project. (See below)

+ Force: Used to add a force object to the project. (See below)

The upper right corner of the view displays some useful information too:

The number of particles is displayed here, and if motion blur is turned on you’ll see the frame multiplier. In this example motion blur is set to 4 frames, and the multiplier reminds you that the particles are being drawn 4 times.

The project resolution is shown here also. (Note: click the project resolution as a shortcut to open the Project Settings dialog so the resolution or motion blur settings can be changed.)

Note that the particle count is usually the main factor in determining performance. If your project is too slow,  particle count is most likely too high — reduce the “number” value or disable emitters.

(The number of motion blur frames and the project resolution are both set in the Project Settings dialog, unless running as a plugin, when resolution is set by the host, and motion blur frames might also be set there.)

Interacting with the Composite View (Stage)

Besides the zoom and motion blur controls discussed above, there are other ways of controlling the Stage.

• Scroll/Pan the Stage by holding the spacebar then clicking and dragging in it.
• Zoom In using Cmd+ on (macOS) or Ctrl+ (Windows)
• Zoom Out using Cmd- on (macOS) or Ctrl- (Windows)
• Toggle Motion Blur using Cmd-B (macOS) or Ctrl-B (Windows)
• The “F” key will Fit the Stage to the View size

You can also zoom using the mousewheel or trackpad when the mouse cursor is positioned over the Composite View.

Using After Effects Camera (Plugin version only)

Besides the built-in camera when Particle Illusion is set to 3D mode, it’s possible to use the After Effects camera:

Just check the “Use Comp Camera” parameter before launching Particle Illusion.

Then inside PI, you won’t see any built-in camera controls, but the view in the Stage will be set to whatever the AE camera is for that specific frame.

Note that the other indication that the AE camera is being used when in the Particle Illusion application is that any camera animation will automatically be applied in the Stage.

(Note also that changes to the 2D/3D button will not make a difference.)

Motion Tracking and Masking (Plugin version only)

When Particle Illusion is used as a plugin, motion tracking and masking are available, powered by Continuum’s integrated Mocha tracker.

With this tracking you can essentially “pin” an emitter to a feature in your shot — for instance a train’s smokestack — moving it automatically without requiring you to manually animate the emitter position.

To track the position of an emitter, select “Emitter” for the Transform / Tracking parameter in your host application:

Then expand the “Motion Tracker / Mocha” group and click the “Mocha Motion Tracker” button:

This opens the Mocha interface, where you can then track the emitter position:

The details of how to use Mocha are provided elsewhere, but the key concept to understand when using it with Particle Illusion is that the “Transform / Tracking” parameter must be set correctly:

• “Emitter” if you want to track an emitter position in a shot with a stationary camera
• “World” if you want to track the camera movement only (with emitters that don’t move or that you’ll animate manually)
• “World + Emitter” if you want to track both camera movement and emitter position

Mocha not only provides tracking, but also masking. When in the Mocha interface, there are several ways to draw masks: freehand, as X-splines, with the magnetic tool, and more.

Once the masks are drawn, they also get tracked by Mocha, reducing or eliminating any manual repositioning. There are parameters for feathering, inverting the mask, and more:

Both the Mocha tracking and masking are essential features to integrate Particle Illusion effects into your projects.

Particle Masking (Plugin version only)

The Mocha masks are traditional composite masks, but there are others ways to use masks with Particle Illusion.

There are three ways to use a mask:

“Particle Creation” - The particles are created only in the non-zero part of the mask. After creation the particles live out their lives normally, and can move outside the mask area.

“Render Mask, Standard” - The mask is used as a standard composite mask, with particles visible only inside the mask area. Particles will be clipped by the mask. (This type of masking is possible with most hosts, but is handy when rendering directly from Particle Illusion.)

“Render Mask, Full Particles” - Similar to the previous option, but particles are not clipped: the full particle is always drawn. (Larger particles show this more clearly.)

A: “Particle Creation”, B: “Render Mask, Standard”, C: “Render Mask, Full Particles”

The source for the particle mask can be either a Layer/Source input, or the Continuum PixelChooser:

“Layer” (or source input depending on your host) is the simplest way to access a mask, while the PixelChooser gives you many more options, including preset shapes, gradients, choosing specific channels, adding blurs, and more:

Note that regardless of the mask source, Particle Masking can only use the mask from a single, static frame, set using the “Use Mask from Frame” parameter.

Composite Style / Apply Modes (Plugin version only)

Also when used as a plugin, Particle Illusion can be applied using a variety of transfer modes. The default setting is “Direct (Classic)”, which composites the particles directly over the source layer — this is the method used by the legacy particleIllusion application.

Using this mode gives you access to some basic color correction parameters:

Although this “Direct” composite style may be ideal for some projects, a wide variety of apply modes become available once the “Alpha + Apply Mode” Composite Style is selected:

With an apply mode selected, you then have the ability to not only mix the selected mode with Normal mode using the “Apply Mix” value, but you can adjust the Opacity of the effect too — both of these give you a huge amount of control in blending the particle effects into your project.

You can also adjust Brightness, Contrast, and Gamma regardless of which Composite Style is chosen, but when “Alpha + Apply Mode” is selected you can also choose to apply these adjustments to just the particles, or to the composition.

Particle Properties (Plugin version only)

Under the “Particle Properties” section you have access to some of the Particle Illusion native parameters:

These are provided not just for convenience — as they let you adjust some aspects of the particles without having to jump back into the PI interface — but also allow you to animate and utilize your host application’s scripting capabilities.

Note that it’s best to think of these parameters as an additional level of scaling factor being applied; they can’t add something that is not there in the emitter already. For example, if the particles in the emitter have a velocity of 0, the “Velocity” parameter in this “Particle Properties” section will have no effect: 100% of 0 is still 0.

Glow (Plugin version only)

You can add glow to the particles by clicking “Glow On”:

Once enabled you can adjust intensity, color, radius and threshold, and when using “Alpha + Apply Modes” as the Composite Style you can choose to apply the glow to the particles alone or the composition.

Beat Reactor (Plugin version only)

When talking about the Particle Properties above, it was mentioned that you can animate those parameters or use the host’s scripting capabilities. Even if your host does not have scripting you can still make particles react automatically to an audio track by enabling Beat Reactor:

After selecting an audio layer (or external audio file based on which host application you’re using), you use Beat Reactor to set frequency ranges and tie them to specific Particle Illusion parameters.

Beat Reactor works in the same way in Particle Illusion as it does in the other Continuum effects that contain it — more information on Beat Reactor here.

Tip: if you want to make the particles “pulse” in time to the audio (change size to the beat), control the “Master Size” parameter, not “Size”.

Note that if you use Beat Reactor to drive specific Particle Property parameters, and have manually animated those same parameters (or have used your host’s scripting to animate them), results may be unpredictable.

Path/Light/3D Layer Follow (plugin version, AE only)

In After Effects you can have Particle Illusion emitters follow a path (mask/text) or attach to Lights or 3D layers:

To enable this feature in the Particle Illusion plugin in After Effects, set “Transform / Tracking” to “Emitter”, then the “Take Path From” options available are Comp Lights, 3D Layer, or Mask/Text:

With “Mask/Text” selected, the parameters in the “Mask/Text” section are enabled, and you have several options in the “Choose Path” parameter:

As seen you can choose to follow all masks simultaneously or sequentially, choose a single mask to follow, or follow text simultaneously or sequentially.

(Note that all of these options are always enabled even if masks or text layers are not present in the composition so you’ll have to know which option you need.)

To trace all text characters or masks at the same time, choose the “Simultaneously” version. This will make copies of the emitter for each letter (or mask).

Next you select the Mask/Text Layer:

This allows you to have the text/mask on a different layer — the chosen layer does not even need to be visible.

Note that because of the multiple copies of the emitter, you may want to use the “Number” parameter to decrease the number of particles created.

Animate Path Location Parameter

In order to actually trace the letters (or other paths), you need to do one more step: animate the “Path Location” parameter so it starts at 0º and then some time later increases to 359º (or 1 revolution).  You can set it to multiple revolutions if you want the emitter(s) to loop around the path multiple times.

You can use the Path Direction parameter to set the direction of tracing, or even have it trace one direction then reverse.

If you instead want each character or mask to be traced in turn (one after another), choose the “Sequentially” option.  Remember that the emitter position is being offset here, so if the emitter is moving too quickly — when tracing out a long text string for instance — the details won’t be preserved:

The answer is to either have the “Path Location” parameter animate slowly, or only use masks that don’t have small details or corners. (Or stick to the “Sequentially” option.)

Comp Lights and 3D Layer are similar to Mask/Text, except the emitters are attached to the selected objects — there is no “tracing” involved — so many of the parameters that were used for mask/text are disabled.

There are several options for selecting which lights will be used:

Note that if your comp has several lights that will be used for emitters you may want to decrease the “Number” parameter as multiple copies of the emitter will be created automatically.

For 3D layer, you can select a single layer to use for attaching an emitter.

Mask/Text Emission (plugin version, AE Only)

In After Effects you can not only animate emitter position using masks and text (as seen in the previous section), you can also use masks and text as emission sources.

The “Emitter Type” parameter determines if the emitter will be as defined by PI, or if it will use a mask or text for emission instead:

After selecting “Mask/Text”, the “Emission Mask/Text” parameters are enabled:

The emission options are self-explanatory: “All Masks, Selected Layer”, “Single Mask, Current Layer”, or “All Text, Selected Layer”.

For the options based on “Selected Layer”, use the “Mask/Text Layer” selector.

Here’s an example using “All Text, Selected Layer”:

Note that it doesn’t matter what the emitter shape was in PI: point, line, sphere, 3D Model. Once you select Mask/Text Emission, it is internally converted into a “line” emitter (that is then fit to the mask or text path). Switching back to “Defined by PI” will restore the original emitter shape.

Important: Using masks or text for emission can greatly increase the number of particles that are created, so you may want to decrease the “Number” parameter in the Particle Properties section significantly before selecting mask/text emission.

It’s possible to use both Mask/Text emission and Mask/Text position offset at the same time – for instance to have particles emitting from text, then having that text move along a separate path.

Particle Influencers (Deflectors and Forces)

Although Emitters are the main objects you’ll be using in Particle Illusion, there are two other types of objects that will influence particles and make your projects more interesting: Deflectors and Forces.