Am I the only one trying to create a displacement chain that works in maya the way a normal map/bump map chain works? The sort of chain you can hook up to set driven keys and add in a little bit of each displacement map when needed? I’ve heard a lot of suggestions from chaining the alpha offsets in the color balance to using a layered texture node. Those do work but only with procedural and color based inputs in maya, we’re dealing with alpha here. I found that with these flawed techniques that I could only push out displacement but not push in. But this network does both, adding positive and negative displacement.
NOTE: This uses that free 32 bit displacement exporter plugin that the good folks at pixologic have posted on their website. AND… this is all rendered in mental ray.
STEP 1. GET THAT ZBRUSH 32 bit exporter from their website and install it.
The SetRange is the first part. It converts the file to maya’s displacement standards. This is so you no longer have to screw with the alpha gain and offset in the color balance of the file nodes (no more of that crap). Then it goes through a multiplier node used only as an on/off switch, and then they’re all added together with the add node. If you’re going to ask, I tried using the alpha gain for adding in the displacement but doesn’t seem to work accurately with these zbrush exports. All you have to do is slowly increase the Input2 in the multiplier nodes from 0 to 1 to get the slow push in for each particular displacement map. Best thing to do is to hook this up to a GUI with an up and down bar (made of square curves) through set driven key and looked at from a front view camera, moved far away from the scene. Another thought is to make a bogus blend shape and use the up and down bar of that to drive the adding in of each map also. From here (if you only have 3 displacement maps) you can either cut to the chase and plug the output3 X of the add node to the displacement of the displacement node, OR…(if you have more then 3 displacement nodes) throw another add node on the barby and add two adds like the still above, and then…. plug the FINAL output3 X of the add node to the displacement of the displacement node. And so on and so forth. The add node only adds 3 nodes at once. Final touch, middle mouse drag your displacement node over your desired material and choose displacement map. Now assign the material to your object.
STEP 13. Remember I mentioned that bounding box option pictured in step 10. Well re-select your geometry and set that bastard high, really high. It’s basically limiting how far out your displacement can go. When your geometry gets pushed out too far (sometimes your layered cake can get out of control) it “hits the wall” and your displaced object will look like it’s covered in tree trunks. Usually all you need to do is hit that calculate bounding box scale button at the bottom. The number that gets calculated is usually good enough but if you get that weird decapitation effect on your displacement, then double the numbers to insure no cut off during render time. Honestly I don’t see why you can’t just put all three input boxes to some ridiculous number like 1000,1000,1000. I haven’t seen any performance issues as yet so go nuts.
Now you can go into your render globals for mental ray and up the ante. You can also raise the settings in the mental ray approximation node attached to your geometry for finer detail. I recommend using maya 7. It finally got its act together with mental ray. Still buggy, but the renders are solid now and if you set your shadows right for lighting you shouldn’t get artifacts. I hope this opens a door of creative opportunity for you all. It would be cool if someone could do a tutorial on HDRI, SSS, and compositing HD footage integration with CG. If this shader network can be compressed (I’m sure it can), just let me know. Remember, we’re here to help each other.
Enjoy.
Matt Skonicki
Cinematics Character Artist
Midway Games
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