Does Collada have support for layered textures? If so, does anyone have an example of a simple file with this feature?
Yes, COLLADA 1.4.x has support for multiple textures, and texture coordinates.
1.4.1 has introduced the <bind_vertex_input> to help with this.
This post has an example on how this works.
Please post here if you have follow-up questions about multi-texture.
Thanks for the informative reply. I now understand how to assign multiple textures to a face, but I don't understand how to control the appearance of the textures when they overlap. Is there a way to set the display priority for overlapping textures?
Look at the effects profile for the rendering API that you're using. For example, we have <profile_GLES> and <profile_CG> for setting up the rendering pipeline for those specific API. This setup would include texture blending.