View Full Version : displacement woes in mr

10 October 2011, 03:51 PM
I wish I had a more precise and clear problem to present, but in all honesty I'm having trouble figuring out what, and if I've done something wrong the past few years, or if this is some incurable bug in maya that is destined to plague me : /

Usually, when I set up complex shaders, I'll do so in a clean, new scene. I never have problems fine tuning displacement this way. However, when I bring things back into the main scene, and continue working. Some amount of time, hours, or days. I'll go to change a setting in my displacement, in the approximation editor, and absolutely nothing seems to change on render. Like it was locked down or something.

Right now my issue is a scene I'm working on caps out on ram, and keeps on rising. Basically the render never even starts final gather. I keep disconnecting displacement nodes from the shading groups, and downsizing textures to the point where I know there should be hardly any memory footprint, and still the memory seems to be eaten up.

I was wondering if anyone has had issues like these, or any luck debugging this kind of stuff.
It's really frustrating when I go into the approx editor, and turn subdivisions down to, say 0 and 1. and still see the displacement presampling take exactly the same amount of time and memory it did before with 5 and 7 subdivisions.

I'm using raytracing as primary, bsp2, maya 2012

EDIT: I should also note I usually tend to use the "fine" displacement approximation method, since the help docs say it's flushable with mental ray. Is there any recommended settings or work flows?

I use alot of procedurals for my displacement too.

10 October 2011, 05:48 PM
Here's a visual on what seems to happen memory wise, regardless of what textures are loading, and what objects have approximations, or what subdivisions those approximations have.. (

Uploaded with (

10 October 2011, 05:56 PM
Looks like I unfairly blamed displacement here, hid my instanced forest, and things went smoothly as could be.

10 October 2011, 09:15 PM
Looks like I unfairly blamed displacement here, hid my instanced forest, and things went smoothly as could be.

Might I suggest you use the mip_binaryproxy node for your trees?

djx has a great article on it.

10 October 2011, 10:47 PM
it's a good plan, and I'll probably find a way to utilize it next time. I like to leave my paint effects history on, so there's more than 1 piece of geo, and 2 shaders usually. the tutorial mentioned it has to be a single piece / single shader setup, do you know if that's still true with later version of maya?

10 October 2011, 01:57 PM
You can use more shaders but only one mesh. You will have to assign the shaders to different faces of the standin geometry, but it works.

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10 October 2011, 01:57 PM
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