Particle Blob

Particle Blob

Shader Type: Particle (texture)

Output: Color (RGB) value

Renders particles as 3D blobs that can blend into each other. By default, this shader is attached to the Fluid operator.

Name

The shader’s name. Enter any name you like, or leave the default.

Render Properties

Geometry

Surface Evaluation:

Blending Amount	The frequency at which individual particles merge with others. A value of 0 prevents a particle from merging with its neighbor, while 1 is full blending.
Blending	The attributes of the particles, color, and bumps are blended using the selected algorithm: Blend using weighted influence, Sample from greatest influence, Averaging.

While you cannot blend blobs between multiple particle clouds, you can blend between multiple blob particle types on the same particle cloud.

Texture Projection

Type	Texture projection type generated for the spheres: Spherical, Cylindrical, Lollipop, Particle Local, Cloud Local, or World Coordinates.
Blend Texture Coordinates	Instead of using separate texture coordinates for each texture lookup, this option adds the texture coordinates together using the blobs’ influences.
Use Particle Rotation	Applies a particle’s rotation on the texture projection.

Effects

Burn	Adds the particle’s RGB values together when particles overlap in space (sometimes called color burn or additivity). This lets you create bright spots of colors and glows where many particles are on top of each other.
Self-Shadowing Factor	Shadows cast by the particles onto themselves are attenuated by this factor.

Static Blur

Static Blur	Adds extra transparency as the normal gets more perpendicular to the viewing direction. This makes the spheres transparent on the edges and fully opaque through the center.
Width	Inflates the diameter of each particle by this number of units.
Falloff rate	Controls the transparency falloff rate. Rate of falloff increases with larger values.

Shading Properties

Apply Shading

Applies a simple shading model to the particles. If not selected, only shadows are calculated, and the particles are still visible even if no lights are applied to the cloud.

Ambient

Type	The way in which the ambient color is calculated: % of Base Color (particle type color), Use Ambient Color (the values of the Color sliders below), or None.
Color	When you select Use Ambient Color as the Type, this is the surface’s underlying ambient color, which gets modified by the scene’s ambience. To get luminescent particles, use a high value for this parameter.
% of Base	When you select % of Base Color as the Type, this is the percentage of the particle type’s color (the base color) to use as the ambient color. To “blast” the base color, enter values higher than 100%.

Specular

Type	The way in which the specular color is calculated: % of Base Color (particle type color), Use Specular Color (the values of the Color sliders below), or None.
Color	When you select Use Specular Color as the Type, this is the color of the surface specular highlight.
% of Base	When you select % of Base Color as the Type, this is the percentage of particle type (base) color to use as the specular color.
Shininess	Shininess of the specular highlight. Lower values result in a larger highlight.

Global Illumination

Irradiance

Irradiance determines how much color the particle type receives from other surfaces during final gathering.

Type	The way in which the irradiance modifier color is calculated: % of Base Color (particle type color), Use Irradiance Color (the values of the Color sliders below), or None.
Color	When you select Use Irradiance Color as the Type, this is the color received by the particles.
% of Base	When you select % of Base Color as the Type, this is the percentage of the color received from the particle type.

Radiance

Radiance determines how much color the particle type transmits onto other surfaces.

Type	The way in which the radiance modifier color is calculated: % of Base Color (particle type color), Use Radiance Color (the values of the Color sliders below), or None.
Color	When you select Use Radiance Color as the Type, this is the color transmitted by the particles.
% of Base	When you select % of Base Color as the Type, the color that is transmitted is this percentage of the particle type’s color.

Make Connections

Connects different shaders to this one.

Connect To

Sprite	Connects the sprite shader to this one.
Shape	Connects the shape shader to this one.
Color Gradient on age	Connects the particle color gradient shader to this one. The gradient shader works on the particle’s age % by default.

Making Transparent Particles

There are three basic ways in which you can create transparent particles with the Blob shader:

• On the Particle Type > Color page, set the Alpha value for the level of transparency you want. Then on the Shading Properties page in the Blob shader, set the Ambient - Type to Use % of Base Color and set the % of Base to 100% or more to see the effect better.

• Plug the Particle Color shader into the Color input of the Blob shader to override the particle type color. In the Particle Color shader property editor, select Override Particles - Alpha and set the New Color - Alpha value to the level of transparency you want.

• Plug the Particle Gradient shader into the Color input of the Blob shader to override the particle type color. In the Particle Gradient shader property editor, select Alpha and set the alpha value and the gradient control to the level of transparency you want.

As well, you can plug the Raytracing > Transparency or Opaque shaders into the Color input of the Blob shader and set their values to an appropriate level of transparency.

Autodesk Softimage v.7.5