UV Mapping Subdiv Surfaces
Maya 2012 Tutorial
How to Create a UV map for a Subdivisional (Subdiv) Surface in Maya
Subdiv Surfaces are actually two objects in one. There is the polygon cage that defines the Subdiv Surface and then the actual rounded organic object that is rendered in your scene.
Whenever you apply a texture map to a Subdiv Surface, you are applying the map to the polygon cage.
Create a new project, set your project and save a new scene in the project's scenes folder. For more information, see topic, Starting a Project.
Add a subdiv cube to the workspace by choosing Create > Subdiv Primitives > Cube.
You can view the subdiv object and the polygon cage that defines it by choosing Subdiv Surfaces > Polygon Proxy Mode from the Surfaces menu set.
Select the object and open the UV Texture Editor by choosing Window > UV Texture Editor. Press the f key to view the full layout.
The lines of the UV layout are created by the polygon cage that surrounds the subdiv object.
To save your image as a template for Photoshop, choose Polygons > UV Snapshot.
Note your image name and location. Set your image size using multiples of 128 (i.e., 256, 512, 1024, etc.).
Save your image as a tif file so you can open it in Photoshop. Press the OK button to save your image.
Open your image in Photoshop. By default it can be found in your project's images folder.
In Photoshop, double-click the Background layer to make it a transparency layer. Add a new layer below the template layer.
Double-click the upper layer icon to open the layer options. In the Blend section, drag the This Layer black slider from 0 to 2 and press OK.
Paint the lower layer, using the template in the upper layer as your guide.
Delete the upper layer in the Layer panel, then delete the Alpha channel from the Channels panel.
Save your flattened image in your project's sourceimages folder. Name the image texture01.tif.
Returning to Maya, select the cube, then right-click the cube and choose Assign New Material > Lambert.
In the Attribute Editor, click the checkerbox next to the Color slider. In the Create Render Node, 2D Textures section, right-click the File icon and choose Create Texture.
In the Attribute Editor, file tab, click the Image Name folder to navigate to your image (texture01.tif). The image is located in your project's sourceimages folder.
To disable the poly proxy mode, select the object and choose Subdiv Surfaces > Standard Mode from the Surfaces menu set.
Add a light to the scene and click the Render Current Frame icon to see the subdiv cube with it's new texture.
Why an Alpha Channel?
In Step Eight we chose to save our template as a tif image. Maya automatically adds an alpha channel with tif files.
If we had chosen jpg, no alpha channel would have been created. If you attempt to add an image to an object with an alpha channel, the alpha information is sometimes automatically connected to the shader's transparency node.