3D Paint

Painting Textures with Maya's 3D Paint Tool. 

Introduction  - Painting 3D Textures

A texture created with Maya's 3D Paint

Using Maya 3D Paint

1 -  Open the Tutorial Scene 

For this tutorial, open the scene: 

/mtor/scenes/3D_Paint/model.ma

(Where are the scene files?)

Looking at the scene, we find one simple Maya subdiv. We'll paint onto the surface, and then attach a Slim shading network to attach that image.

 

 

2 - Check UVs

Before using 3D Paint, the model's UVs should be arranged appropriately. We can view the models UVs by selecting the object and opening Maya's texture editor:

Window-> UV Texture Editor

Arranging UVs can be an art in itself, so we won't cover all the details here, but usually it's good to avoid having overlapping UVs, and it's good to keep the UVs inside the 0 to 1 grid. These UVs satisfy both these criteria.  

Laying out UVs properly allows a 2D image to be applied to a 3D surface with arbitrary topology.

UVs ready for 3D painting

3 - Maya Subdivs: Check UVs in Poly Proxy Mode

This step only applies to Maya subdivision surfaces, when using NURBS, polygons, or MTOR subdivs, we can ignore this. But this is an important issue when using Maya subdivs . . .

When working with Maya subdivisions, we need to be aware that there are UVs associated with the subdivision surface, in "Standard Mode", and another group associated with the underlying polygonal mesh, in "Polygon Proxy Mode". 

MTOR honors the polygonal UVs, associated with polygon proxy mode. The subdiv UVs contain hierarchical subdiv information that MTOR does not interpret.

For best results, arrange the model's UVs as a polygon, then convert it to a Maya subdiv. 

Here the UVs of the model were arranged when it was a polygon using Maya's texturing tool:

Edit Polygons-> Texture-> Automatic Mapping

(For more info about working with Maya subdivs see: Maya Subdivision Surfaces)

Polygon Proxy Mode good for UVs


Different UVs  are associated in Polygon Proxy mode. Notice there are fewer UVs in the "pointy" areas, than in the image in step #2.

4 - Prepare Textures

With good UV grooming, we can bring up the paint tool: 
Texturing-> 3D Paint Tool

1) Set the attribute to paint, in this case Color.

2) Set the Image Format to Tiff, a chosen format for MTOR.

3) Next Assign Textures . . . choose an image resolution.

Now we're ready to paint.

Crucial bits of Maya's 3D Paint Tool 

5 - Paint on Surface

Doodle with 3D paint
 

Or we can enable "Update on Stroke" which will save the texture to disk, well, on each stroke.

Our new texture appears in our current project . . .

3dPaintTextures/model/ subdiv_modelShape_color.tif 

The 2D texture created with 3D Paint

 

6 - Construct the Slim Network 

Build a shading network for the new image.

7 - Render with the new Texture

Model with texture created with Maya 3D Paint 

Tips and Tricks for working with 3D Paint

Note A - Optimizing UV Layouts

Remember, as discussed above, when working on Maya subdivs, edit the UVs when in Poly Proxy Mode. Don't edit UVs in Standard Mode, MTOR cannot interpret this hierarchical UV data and relies on the UVs in Poly Proxy Mode. However, when editing the UVs in Poly Proxy Mode, the hierarchical UVs will not be displayed and will remain in place, which will cause a disparity between the UVs MTOR sees and the UVs Maya sees, and may create issues with 3D paint. For best results, edit the UVs with the model converted into a polygon, and when the UVs are arranged properly, then convert it into a Maya subdivision surface.

For more information about using Maya subdivision surfaces and MTOR see: Subdivision Surfaces.
  

UV Layout for model

Resulting 2D map created with 3D Paint