In RGB, I chose 150, 150, 150 as the values, which make grey. Illustrator makes it easy to see highlights and shadows on your 3D objects if you use grey. The best rule of thumb that I have for working with 3D objects in Illustrator from scratch is to always make your base object grey to start out with.

I made it nice and big on my canvas, and the proportions don’t really matter, because I am going to be re-positioning each letter individually later. Keep it simple and your type will look good and you can avoid headaches later. Choose a bold typeface without a lot of extra frills and serifs. This is one of the most popular things to do with 3D is to make 3D typography. Changing the colors of your objects or text can really be a pain, but I have some tips that will make working with 3D objects in Illustrator a little easier for you. The other thing is that the controls for 3D objects in Illustrator aren’t that straight-forward. Yes, Illustrator will allow you to do a decent amount of 3D work, but working with 3d objects in Illustrator can be a pain if you don’t know what you’re doing.

3d illustrator tutorial