Re: Maya Crashes everytime I render a frame

it is possible that the raytracing in maya caused the problem. I would create a new camera anyway and try rendering through that. The perspecive camera can get corrupted, and since the perspective camera settings get constantly overwritten when importing multiple scenes its likely it could have been corrupted somehow.

As for test renderings, you might as well use mental ray if it works since thats going to be your target renderer for end of project.

As for the empty UV set error, this means that you have polygon models in the scene which have no UV information in the default UV set. This probably means textures are not viewable at all on these surfaces. You should use some form of UV projection tool on these models once you've completed modeling to get them to render correctly.

When you do finish all of your modeling I suggest breaking your models down into manageable chunks and referencing them into the scene rather than importing them. It makes it far easier to update a main shot with changes to models or textures later in the production process. Plus you can unload heavy parts of your scene that you aren't currently working with that way. Just be aware that you don't want to do modeling changes on a maya scene that has been referenced into your scene. Always do modeling changes in the scene that holds the model directly. This is why I say break it up after you finish modeling.