The attached zip includes a pickup part for the Rear Bumper slot called "Roll Pan". I did mostly OK with it I think: I got the mesh made and into the game and modified a jbeam to work acceptably. I UV'd it to take the body color from the hood like the stock body-colored bumper does. That is when I noticed that the surrounding bodywork seems to have some shadows baked on somehow. I'm looking at the materials for the pickup and after looking at all the textures (diffuse, specular, normal) I don't really see where those shadows are coming from. Any ideas on how to get some shadows/flatness towards the bottom of that roll pan? Ideally I'd like to get this part to play as nicely as possible with other game-components (parts, skins, etc) and have it look good at the same time.
I got some help on this. You shouldn't need to bake in any shadows. My stuff looked OK inside Blender (eg from the .blend file), but I never re-imported the DAE after I noticed the problem in-game. That would have told me a lot right away! I was duplicating my mesh so that I could UV an inside and outside texture. This was a bad idea. Instead I ended up using a combination of two modifiers: solidify and edge split In order to get the modifiers to work correctly I had to use CTRL+A to apply rotation and scale, even though I don't think I'd really scaled anything. (This also made the face-normals overlay display correctly again!) Speaking of normals, the problem seen at the bottom of the roll pan in the pic above is due to an inverted normal. It wasn't inverted when I started, but somewhere along the way with the various bad things I did it became inverted in the DAE. The second UV map is always the right one for skins. Don't forget to map that one as well if you want skins to work correctly.
