Dynamic Attributes for Rendering

User Guide > Rendering and Render Setup > Rendering > Rendering nodes > mental ray for Maya Dynamic Attributes for Rendering >

The following dynamic attributes are designed to work on Maya shape nodes. Some of these attributes are not always visible by default in the Maya user interface. However, once you have created the attribute, you can view and edit the value in the Extra Attributes section in the Attribute Editor.

mental ray Derivatives

Use this attribute if you want to use mental ray derivatives for NURBS and subdivision surfaces (to interact with shaders), instead of the default mental ray for Maya derivatives.

Create this attribute on the shape node as follows:

addAttr -ln "miDerivatives" -at "enum" -en "none:first:second:both" -dv 0 pSphereShape1;

Values within the range of 0 to 3 are supported for -miDerivatives.

0 = no derivatives
1 = first order derivatives
2 = second order derivatives
3 = first and second order derivatives

mental ray Ray Offset

Use this attribute to specify how much to offset a ray from the geometry. Ray Offset is useful in scenes with raytraced self-shadowing artifacts.

Create this attribute on the shape node as follows:

addAttr -ln miRayOffset -at "float" -dv 0.0 pSphereShape1;

This attribute is often used to help resolve shading artifacts such as the tessellation that appears in shadows or raytracing effects.