Well, I have a question (just one, for now) : Is it possible to add/remove an object in an animation, you know, to appear in some frames, but dissappear in others (without using Video Sequence Editor). Remember, I want it NOT to dissappear outside the camera view (it uses more CPU I think:confused: ). Thanks!
[QUOTE=David Shan; Remember, I want it NOT to dissappear outside the camera view (it uses more CPU I think:[/QUOTE]
I’m not sure what you mean, I think you meant not by by just moving the camera ?
You can animate the Alpha value of a Material (how transparent it is), which in effect will make it disapear either suddenly or at whatever rate you want (Casper the friendly ghost ? 
Add a material to a mesh, then with the mouse hovering over the Material buttons, press I and choose Alpha (or add the Material, then in IPO window choose Material as the IPO type, then click on the Alpha animation channel on the right side of the screen and add points with CTRL-LMB in the IPO window.
Mike
Thanks, I will use this!
You can also keyframe the object to a layer that the camera doesn’t render.
Now that’s a good idea! Both of you, thanks.
I think the last idea is better, cause I think the first one will render it all still, just transparently.
Well it depends how you want to disappear. If suddenly then the 2nd way would be the best, if slowly the 1st method… and than after it fades out add in the 2nd method to stop the computer from using whatever resources it uses.