OC Textures

What size do the textures have to be to fit in with the object creator?

Any dimension in powers of 2 is needed not just for Object Creator, but for any 3D application in general. Other dimensions are slower to load and result in poor quality so never, ever use texture dimensions other than those in powers of two: 2,4,8,16,32,64,128,256,512,1024,2048,4096...

Technically, width and height can use any number that's a power of two, such as 512x256. However, you should keep textures square unless you somehow absolutely need a rectangle. (The NoLimits panoramic background texture is the only example I can think of where you'd want to use something like 1024x256 [or some dimension close to that], but otherwise there's not much need nor purpose to doing so as textures can be stretched and counter-stretched. (That is, non-square textures can be distorted to fit into a square, then when you map the texture in the 3D modeler, you can stretch it out again. This has a negative impact on the horizontal or vertical texture resolution, but is faster for the 3D engine to operate on.)