This page provides information on the User Attributes set that can be added to meshes.
Overview
Allows the user to specify their own attributes, which can then be accessed with the User-defined Color Map (VRayUserColor) and User-defined Scalar Map (VRayUserScalar) textures to provide per-object values for shading attributes. They can also be used in the file name of File nodes to resolve the bitmap file name on a per-object basis. Several attributes can be specified in the string, separated with a semicolon ';' character. User attributes can also be specified on transform nodes. The final string of user attributes for a given object is a concatenation of the user attributes specified on the shape of the object and the user attributes specified on its parent nodes along the DAG path. This allows to conveniently add attributes to a large part of the DAG hierarchy.
Starting with V-Ray 5.0, when user attributes are used in the beginning of a file path, V-Ray treats the path as absolute. For example, if a file node loads a texture from <userAttribute>/texture.png, the path is treated as absolute and the Maya project path will no longer be prepended.
UI Path
||Select mesh|| > Attribute Editor > Attributes menu > VRay > User Attributes
User Attributes
User attributes – A list of attributes separated by semicolons that are assigned to the mesh.
Animated User Attributes
If you need to animate the value of a user attribute, you can create a custom dynamic attribute attached to the shape or transform of an object, and animate that. The dynamic attribute must be named vrayUserColor_attrName or vrayUserScalar_attrName or vrayUserString_attrName depending on the attribute type. You can then use the tag <attrName> in textures like VRayUserColor and VRayUserScalar as well as the file name of a File node.
Note: Creating an animated VRayUserColor attribute will require additional MEL scripting.
Example: Animating a Scalar User Attribute
In this example, the VRayUserScalar texture is used to control the VRayMtl Reflection Glossiness parameter by an animated user attribute.
First the custom dynamic attribute is connected to the transform of the object. In this case, the Cube object is selected. With its Transform attributes opened in the Attribute Editor, launch the Add Attribute window from Attributes > Add Attributes... .
Here the new attribute can be specified. For the purposes of driving Reflection Glossiness, the attribute type will be a keyable floating point scalar. Note the attribute Long name must begin with vrayUserScalar_ in order to be read by VRayUserScalar later.
After clicking Ok or Add, the new attribute is available in the Channel Box/Layer Editor. Animate this attribute by editing its value and keying it at different points in the scene's timeline. To add a key, right click the attribute and select Key Selected.
For this example, the Reflection Glossiness is keyed with a value of 0.5 on frame 1 and 10 on frame 10.
New user attribute with the value keyed
The material and VRayUserScalar texture must be set up next. As seen in the node graph below, the VRayMtl's Reflection Glossiness is driven by VRayUserScalar's Out Alpha. The VRayMtl is then assigned to the Cube object.
The final step is linking the VRayUserScalar texture with the custom attribute. This is done in the VRayUserScalar User attribute name parameter. Note the vrayUserScalar_ prefix is omitted here.
The final rendered results show the Reflection Glossiness value animated between frames 1 and 10.
Frame: 1
Reflection Glossiness: 0.5
Frame: 2
Reflection Glossiness: 0.826
Frame: 10
Reflection Glossiness: 10.0