How do I select the avatar character (3D Model only) from the server API?

Hi Rui -
There is no way to assign a character to a Scene via the API. However you could pre-prepare multiple Scenes (with different characters assigned to each) and dynamically select the Scene based on user choices.

What are you trying to accomplish? let me know perhaps I can suggest a solution.

If you are trying to simulate user creation of characters, you may want to check out a different solution Oddcast (SitePal's parent company) offer for that purpose - the Avatar Framework.
see - http://www.oddcast.com/dev/framework/

Hope this helps,
Gil
SitePal Team

Our website will let users to customize their own avatars. So we need to have a web page where our clients can set their avatars by selecting from a list of models, backgrounds and languages. Is this possible?

If all you are looking to do is select from a pre-defined set of characters (without providing any character editing features, scaling etc.) - then I would go with the approach outlined above - create a Scene for each of the characters you want to support, without background or audio.

Using the API you would duplicate the appropriate Scene per user's selection, and dynamically assign audio and background via api calls.
Will that work for you?
Gil