AC3D - Easy to use 3D software

AC3D and EA Sports Nascar

AC3D is EA's recommended tool for previewing your car paint designs in full 3D before uploading them into the game. See some sample models in AC3D in this video.

To preview one of your textures in full 3D using AC3D:

load one of the 3d model files into AC3D - use menu File->import and select your obj file. The three car model files are also available for download here.
Ensure the car body is selected and go to menu Object->Texture->Load-texture. Select the image file and press OK.