CGTalk - Compositing Z-Depth in after Effects- ANYONE !?

XanderFX

05-17-2005, 11:05 PM

I just got this working in AE from a few weeks ago. Render from Maya an RL A sequence (I'm assuming maya because you mentioned iff. iff doesn't work by the way) sequence make sure z-depth is on. Make sure that your near and far clipping planes are set properly (i.e. not to small and not too large) you can play with them by selecting your camera go into the attribute editor and in the near and far clipping plane boxes hold down ctrl while you LMB drag in the value box. You'll see your model vanish as the far clipping plane gets to close to the camera move it back until its at the maximum depth needed for your animation do the same with the near clipping plane for the closest your models get to the camera.

Then in AE import your RLA sequence and drop it on our timeline then go to Effect>3D Channel>3D Channel Extract. Then in the effects palette select z depth for the 3d channel and you'll need to edit the values for black point and white point to do this right click on the number and select edit value then put in -1 for minimum and 1 for maximum do the same for white point. Now when you adjust the slider you'll see your gray scale image appear blackpoint is controlling your near clipping plane and white is controlling your far clipping plane.

Depending on how you plan to use it either for depth of field or a track matte you'll want to adjust it accordingly.

For depth of field effects I get a nice gradation going from black where I want blur to white for no blur. Then I place the sequence layer above an adjustment layer with box or gaussian blur and then I set the adj layer track matte settings to Luma Inverted Matte and voila!

If you're trying to composite something into a 3d scene in z space just get either your white or black point where you want it and then use the same number for the other point and then use it as a Luma Inverted Matte for you object to composite.

Cheers!