Control primitives using Ptex maps

Create Ptex-based maps to control attributes values based on color values and textures.

When you save the painted map to an attribute, such as Length, Width, or Density, the map values scale the set attribute values based on color. For example creating a Ptex map for the Mask attribute, lets you paint out areas that you do not want primitives to generate. You can also use expressions to change how the Ptex map values affect primitives. See Work with Ptex maps and expressions.

For more information, see About controling primitives with Ptex maps.

To create a Ptex map to set modify an attribute

1. In the XGen Editor, click this icon beside the attribute you want to modify.
2. Select Create Map from the menu that appears.
3. In the Create Map window, do the following:
   • Type a Map Name.

     The Ptex file uses this name.

   • Set a Map Resolution.

     This sets the number of texels per-face the Ptex map will have. For higher resolution textures, use higher Map Resolution values.

   • Select a Start Color.

     When Start Color is Black, the initial map value is 0, which sets the attribute to 0.

   • Click Create.

   The 3D Paint Tool window appears. You may need to click the icon in the Tool Box to open this window.

4. Select a Brush and Color then paint on the mesh.

   Painting white sets the map to 1.0. This scales the attribute values for primitives generated in the painted area by a factor of 1.

   Note:

   If you paint with the Smear or Blur Paint Operations on, turn on Screen projection to avoid possible visible artifacts. You may want to change the default values for the following 3D Paint Tool settings before you begin painting:

   • Blend Mode
   • Stylus Pressure
5. In the XGen Editor, click the save icon beside the attribute you are painting.

   Maya converts the painted texture map to a Ptex file. A preview of the map's effect on the primitives displays in the scene view. If you do not see a preview, ensure that Update Preview Automatically is on.

6. Click the icon to return to the 3D Paint Tool to continue painting your Ptex map, and then click to save and preview your changes.