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Rendering particles with mental ray for Maya
Rendering particles with mental ray for Maya
mental ray for Maya dynamic attributes
Using the Particle Sampler Info node with mental
ray shaders
The Particle
Sampler Info node can be used to provide additional particle shading
control in mental ray shaders.
Although mental ray for Maya can render many
types of particles (including hardware particles like Streak, Point,
Sphere, and so forth) it is only able to use the Particle Sampler
Info node with the following particle types.
- Blobby
Surface (s/w)
- Cloud
(s/w)
- Tube
(s/w)
The particle type can be set via the
Particle Render Type attribute
under the
Render attributes section
in the particleShape Attribute
Editor.
Only the following subset of attributes on the particleSamplerInfo node
are available for use with mental ray shaders:
- outUvCoord
- outColor
- outTransparency
- outIncandescence
- particleId
- age
Follow this workflow to use the particleSamplerInfo node
with a mental ray shader. This example creates a particle emitter
where each particle has a random color and then uses a particleSamplerInfo node
to supply the per particle color information to a mental ray shader.
- Create
an emitter.
- Set
Rate (Particles/Sec) to 300 and set Speed to 5.
- Play
the animation so that particles appear and assign a new
mib_illum_lambert material
to the particle shape.
- Open
the particleShape Attribute Editor.
Under
Render attributes,
set Particle Render Attributes to Blobby
Surface (s/w).
- Click
the
Add Attributes For Current
Render Type button.
- Set Radius to
0.2.
- In
order to access per particle color data, you must add the rgbPP
attribute to the particle shape. The rgbPP attribute is exposed
through the outColor attribute on the particleSamplerInfo node.
In the Particle Color Editor window, select Add
Per Particle Attribute and click Add
Attribute. The RGB PP field
now appears.
- Right
click the RGB PP field in the Per
Particle (Array) Attributes section and add a Runtime
Before Dynamics Expression. Enter particleShape1.rgbPP
= sphrand(1) for the expression and click Create.
- Open
the Attribute Editor for the
mib_illum_lambert shader.
- Click
the map button for the Diffuse channel
and select Particle Sampler from the Particle
Utilities section under the Utilities tab
of the Create Render Node window.
- Play
the animation and preview render with mental ray for Maya. The particles
each have a random color assigned to it.