Could i only draw the object3Ds which are modified per frame?

[kiffa]

In my game, some scene has a fixed camera, so there are some object3Ds which are staying the same per frame(background, trees and so on).

I want to just redraw the object3Ds which are modified per frame(for example: animated objs), don't redraw the others.

How to do this? And how much is the difference of the performance between the 2 methods(one is redrawing all the objects per frame, the other is just redrawing the modified ones.) Could i keep some pixes in the framebuffer instead of refilling it?

[EgonOlsen]

For most scenes, you can't do this, because you'll run into a lot of depth buffer issues that way. If they are really separated, you can try to render your static scene into an npot-texture and blit that as a background image. By sure to use OpenGL ES 2.0 for this, because otherwise render-to-texture doesn't work on some devices due to driver problems.