Sketchfab supports the obj fileformat. This fileformat contains a lot of features. The following features have been tested and are listed here. All features are tested with the sketchfab publisher for 3dsMax. Check out the sketchfab obj features in action here, or on sketchfab.
As you can see, sketchfab also supports embedding a viewer directly in your site. This is done with an iFrame. It’s pretty easy to copy the embed-code from sketchfab to your site or blog. If you’re running a wordpress blog, keep in mind that you need to have admin clearance, otherwise the iframe won’t stick in your post. It’ll just disappear every time you update the post. An example of the embed code is posted here:
<iframe width="300" height="200" src="http://skfb.ly/4i32fe" frameborder="0"></iframe>
Flat, diffuse materials are supported. You don’t need bitmap textures for colors. The diffuse colors come out very bright though. Ambient colors have no influence.
Specular color and glossiness is supported. The highlights come out a bit funky though when using very low glossiness values
Bitmap-textures are supported. Bitmaptextures mix with the diffuse colors, but they don’t mix with the ambient colors. To get the original colors of the bitmaptextures you apply, set the diffuse color to white.
Normal maps within a normal-bump texturemap in the bump-slot are supported. Make sure you name the normal-bump uniquely in the scene. Otherwise it will share a single normal map when using multiple normal-maps.
Transparency is not yet supported
All faces are doublesided for the moment. Adding the possibility of backface-culling (single sided faces) is very high on my wicslist though. Let’s hope it gets implemented in the future!