Method

This node emits particles from an image or video by extracting feature points from the image or video frame. The image or video may be set directly using the Image attribute, or taken from a node connected via the Video Node attribute. Features are extracted by looking for corners or areas of interest in the video frame that make good tracking points.

If the source is a video the feature points are then tracked through the motion of the video. Tracking can make use of motion vectors if a Video Optical Flow node is connected to the Optical Flow Node input.

The location of emitted particles depends on the way the image is supplied to the emitter. If an image is supplied via the Image attribute or linked from a Video node it will be emitted from a unit plane in the XY axis, combined with the transform from the emitter itself. If an Image Plane node is linked to the emitter’s Video Node input the transform from the Image Plane is used, so the particles will emit at the same location in 3D space as the pixels in the Image Plane, assuming the emitter’s own transform doesn’t offset it. If an Image 2D node is connected, particles use the current camera plane to emit particles such that, after transformation by the camera, they map to the Image 2D node’s pixels in the final render.

Example

Transform

Name Description
Position X Move its position along the x-axis in local space.
Position Y Move its position along the y-axis in local space.
Position Z Move its position along the z-axis in local space.
Rotation Heading Rotate the object about the x-axis.
Rotation Pitch Rotate the object about the y-axis.
Rotation Bank Rotate the object about the z-axis.
Scale X Scale along the x-axis.
Scale Y Scale along the y-axis.
Scale Z Scale along the z-axis.

Inherit Transform Channels

Toggle which transform channels should be inherited. By default, all are on.

Attributes

Name Description
Image Override the input image with an image selected from the drop down menu.
Randomness How much randomness is added in the particles movement.
Life Control how low long each particle exists for.
Life Randomness Control the randomness for the life of each particle.
Emission Rate What percentage of the particles are emitted from the emitter per second.
Max Particle Count Set a maximum particle count for the emitter.
Use Thickness Change the thickness of the three dimensional area the particles can spawn in. Only functions if “Use Thickness” is on.
Depth Video Modifies the z position of the particles, based on the input video.
Motion Vector Video Select a motion vector video to apply to the object.
Motion Vector Effect Scales the magnitude of motion vectors when applied to the particles.
Motion Vector Bias Control whether there is a bias towards either axis from the motion vector video.
Avi FPS Change the frames per second the video is played at.
Motion Vector FPS Control the frames per second of the input motion video.
Time Offset Offset the time the effect is running.
Feature Offset Limits which parts of the video emit particles.
Feature Minimum Distance The minimum allowed distance between generated feature points – prevents too many feature points from being spawned in one place.
Track Edge Features Only Toggle whether to track edges, or track the whole image.
Edge Detect Threshold Control the threshold at which the edge can be detected.
Limit Emissions Per Point Toggle whether the number of particles that can be emitted per pixel can be limited.
Emissions Area Min Control the minimum area that the particles will be emitted.
Emissions Area Max Control the maximum area that the particles will be emitted.

Material

Name Description
Colour RGB colour of particles.
Diffuse Control how much the light is scattered from the surface of the object.
Emissiveness Control how much light is emitted by the particle.
Life Colour Affecter Weight Controls how much the result of any Life Colour Shading nodes are blended with the particle’s colour.
Particle Scale Scale the size of the particle.
Dof Amount How much depth of field effects the particles material.
Density The density, for use in some simulations.
Temperature The density, for use in some simulations.
Cooling Rate The cooling rate, for thermal dynamics simulations.
Density Decay Control the rate of decay in the density.
Fade In Time What percentage through the particles life span the particle fades in.
Fade Out Time What percentage through the particles life span the particle fades out.

Inputs

Name Description Typical Node Input
Video Node Video used as a basis for the particle system. Video Loader
Optical Flow Node Video used to calculate motion for the particles. Optical Flow
Video Feature Node The input video feature node. Video Find Features
Colour Control Nodes Control the colours of the particles. Colour Ramp
Transform Modifier Links all transform properties to the input node. Null
Target Node Always faces the x-axis towards the inputs anchor point. Null
Local Transform Override Override the transformation values of the node, relative to its parent. Null

Outputs

The transformation values of thi node will be inherited by its children. Furthermore, Affectors, Shading And Rendering nodes will only be effective to the particles emit by this emitter.