View Full Version : Multi Pass Rendering

07-06-2007, 04:49 PM
Not sure If I am even using the term correctly in the subject, but I have a large scene of a residential development. The scene is made up of about 100 low poly houses and than 64 semi high detailed houses. Scattered across the terrain is about 400 single poly planes with tree images mapped and targeted to the camera. What I am trying to do, if its possible is to render the scene in two passes and then composite it back together in AE. The houses and roads in thei frist pass and then the trees in the second pass. Is this possible to do, and if so can you give me some tips or point me in the direction of a good tutorial on the subject? Thanks in advance and I look forward to hear from you guys.


07-06-2007, 05:51 PM
I suppose the trees are (semi-) hidden behind the houses at times?

It will make sense to use the new scene editor for this.
Basically, the approach I'd take is as follows:
Save the scene as your master scene.
Now Save it twice, once for the housing, once for the trees.

In the trees scene, set the object properties of the housing/roads as follows (-> new scene editor):
Matte Object, Black, Alpha Constant Black
This will still render the trees, but hide them behind the housing.

In the houses scene, just hide all the trees (disable them in the new scene editor).

Now you should be able to composite the trees on top of the houses, but have them hidden if they are actually behind them.

I hope that helps, if in doubt, try it with a small test scene first.


07-06-2007, 06:04 PM
I will give that a try...thanks so much for the help. I always appreaciate anytime someone takes to help


07-06-2007, 06:16 PM
I will give that a try...thanks so much for the help. I always appreaciate anytime someone takes to help

Try it out first... and then thank if you still want to ;)


07-07-2007, 12:48 AM
Nice .. needed this earlier in the week.

Added to the


ps. It does work, right? ;)

07-07-2007, 04:32 AM
I always asked myself how people get multipass rendering to work when there's something hidden. That's why I never did this kind of compositing.
Thanks for pointing to the right settings :)