This page provides information on the PhoenixFD Particle Texture.
Page Contents
Overview
The Particle Texture is a 3D texture that colors the positions of each particle in a particle system. The area around each particle has soft edges and is white by default, fading to black with distance from each particle's position. This area can also use color from another texture, or even use different pieces of a texture for each particle. If a constant color is used, it can either be the same for all particle areas, or it could come from a certain particle channel - Age, Velocity, RGB, etc.
You can plug the Particle Texture in a Phoenix Particle Shader's Color Map and this way you can have different colors for each particle based on their particle channels. You could also plug the Particle Texture in a material and use it to shade the surfaces of geometry objects. If you are simulating liquid that creates a WetMap particle system over geometries, you can use the Particle Texture as a grayscale mask for a Blend material that combines a dry and wet material, so the geometry that is covered by the WetMap particles appears wet, and the rest of the geometry is dry.
UI Path: ||Hypershade|| > Create panel > Maya section > 3D Textures
UI Path: ||Create Render Node|| > Maya section > 3D Textures
Parameters
Particle Systems | particleSystem – Specifies the particle system that will be used.
Use Particles in Local Space | localSpaceParticles – When enabled, the icon transformation can be used to move, scale, and rotate the particles. When disabled, the particles are directly represented in the world space as they are in the file.
Particle Areas
Particle Area Radius (units) | blendRadiusUnits – Specifies the radius of the particle area.
Animate Blend Radius by Age | animateBlendRadiusByAge – If this option is enabled and the Particle Area Radius is animated, the particle Age channel is used to modulate the radius. Note: The particle ages must be exported from the Output rollout of the Phoenix Simulator.
Areas Blending Method | blendingMethod [ 0 1 2 3 ] – Specifies the method for blending particles that have overlapping areas.
Equal | blendingMethod [ 0 ] – All particles add the same contribution to the end result.
Proportional | blendingMethod [ 1 ] – The contribution of each particle is determined by the bell curve value at the current distance.
Biggest | blendingMethod [ 2 ] – The particle with the biggest contribution determines the end result.
Voronoi | blendingMethod [ 3 ] – The nearest particle is used.
Blend Alpha | blendAlpha – When enabled, the alpha of the sampled color texture is blended. Otherwise, it is set to 1.
Area Colors
Color Intensity | amplitudeAmount – The color strength in the particle area.
Multiply Intensity By Size | multiplyByParticleSize – When enabled, the Color Intensity value is multiplied by the particle's Size channel. This option can be used when blending wet and dry materials when using WetMap particles (when Wetting is enabled in the Liquid rollout) because the WetMap particles shrink with time.
Animate Intensity By Age | animateAmplitudeByAge – When enabled and Color Intensity is animated, the particle Age channel is used to evaluate the value.
Color Map | texture – Specifies a texture map connected to the particles. The contribution of each particle is the color from the texture in the Particle Area Radius, fading to black with soft edges or blending with overlapping particle areas using the Areas Blending Method. If no texture is specified, the particle area is white.
Texture Shifting
Shift Color Map | shiftMode – Enabling this option changes the calculation algorithm. Instead of contributing to the resulting colors, the particles instead give shifted coordinates for the texture specified in the Shift Zone field. When the simulation starts, each particle relates to a pixel on the texture, and also to a number of pixels around it using the radius specified by the Shift Zone parameter. As the particles move, they "pull along" the related part of the texture. If the Animate Shift By Age option is enabled, particle age is used to shift the texture rather than particle position. This mode has no effect if no texture is specified in the Shift Zone field.
Shift Zone (pixels) | shiftAmount – Specifies the radius used in Shift Color Map.
Animate Shift By Age | animateShiftByAge – When enabled, the particle age will be used to shift the texture rather than the particle position.
Color From Particle Channel
Use Color From Particle Channel | colorFromPartChan – When enabled, the particle areas are colored using a specified particle channel of the connected particle system, such as Age, Size, Velocity, Position, etc. Note that if the particle channel is a vector channel, such as RGB, Position and Velocity, it can directly be shown as color in each particle area, but if the channel is a scalar such as the Size, Age or ID of the particles, it will produce grayscale color, unless you use the Remap Color option.
Remap Color | partColorRemap – This option remaps a different color for scalar particle channels such as the Size, Age or ID of the particles, or a component from vector particle channels such as RGB, Position, or Velocity. For example, you can remap the particle Age which ranges from 0 (black) for newborn particles to several tens or hundreds (seconds), to a gradient from blue color for newborn particles to red color for old ones, by placing the blue color at position zero in the color gradient and placing the red color at a value that is the maximum particle Age (in seconds). You need to know the value ranges of the particle channels in order to remap them correctly - e.g. Age is in seconds for Phoenix particles, Size is in voxels, Velocity is in voxels/sec, etc. When remapping vector channels, you have to set the Use Color Component option to one of the vector components of the channel.
Use Color Component | remapColorComponent – Specifies the vector component of channels such as RGB, Position, or Velocity to be used when remapping.
X – Uses the X axis of positions or velocities, or the Red channel from RGB color.
Y – Uses the Y axis of positions or velocities, or the Green channel from RGB color.
Z – Uses the Z axis of positions or velocities, or the Blue channel from RGB color.
Length – Uses the length of the particle channel. Can be used with the Velocity channel when you need to remap the Speed of the particles to colors. If X, Y or Z are used with Velocity, this will remap the Speed respectively in the X, Y or Z directions.
The Remap Color gradient stores its attributes with the partcolor_p, partcolor_c and partcolor_i script names.
You can render out the Color From Particle Channel as a separate render element by using the Phoenix Particle Texture as an input for the Extra Texture render element and turning on Render as Geometry in the Particle Shader's options.
Setup for shading dry and wet materials
The PhoenixFDParticleTexture can be used to blend between two materials. In the example below, two different V-Ray Materials are set as the Base Material and Coat Material of a V-Ray Blend Material. The PhoenixFDParticleTexture node's Out Color is set as the Blend Amount map.
This setup can be used when rendering the Wetmap particles of the Phoenix simulation. You can use a PhoenixFDParticleTexture to read the Wetmap particle system and then blend between two materials - a dry and a wet one.
