How do I mask an object so that it does not appear went it goes behind a certain space? For example, I want to animate a rod and make it go partially behind a donut shaped object (with a hole in the middle). I don’t want the rod to appear in the hole, however, but only to appear on either side of the donut.
This is what I get:
----(-)----
This is what I want:
----( )-----
(the brackets are the donut)
Oh ya, I also tried that tutorial on BlenderWars but it didn’t help.
Wow, that’s an unusual request??? Is it for a film clip or a still, or perhaps a real time sutuation?
It would be easy to cover it up in a still, but right now, I can’t think of any way to hide it while it travels through an object?? Hummmmmm
Anyone else? I’ll keep thinking, but that’s not my strong point, LOL 
Ingie
Yeah, it’s for an anim.
what about a global-mapped alpha map?
if I understand your question right.
What’s that? 
you could make a gradient texture that would reduce Alpha to 0.0 in the middle of the donut.
Martin
I’m sorry Theeth, but how would that make the stick, or whatever, disappear in the center, as it’s going through the doughnut? I don’t think I understand?
Thanks, Ingie
yes…you should put alpha at 0.0 inside the middle and then everything there won’t be seen.
you should also be able to fake it using rvk’s. Create two rods on either side of the donut so that there is no rod in the middel. Then make the left end of the left rod come closer to the donut while the right end of the right hand rod goes further away from the rod at the same rate. if done correctly it should simulate the effect.
Djurre
I made an example file, I hope it’s more clear that way.
cheers,
Martin
Perfect! Thanks a lot theeth! Now i just have to figure out how to apply it to my project.