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Negative displacement in material.

Tommy L

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Is it posible to do a negative displacement in a material?? I just spent all day making displacement maps and theyre no good. Neither is the model that took me all day....bugger.

Can I use a traditional displacement with MR? I want negative displacement in the material!!! AAHHHHGGGG!!!


The image shows my disp map on the black material. I cannot just invert the map because it displaces all of the material except the creases. Then the creases look fine, but then the object is 'too large' because of the displaced geometry.


Surely Im missing something, there must be a way of doing negative displacement.


Help much appreciated.

Edited by Tommy L
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I can get it to do what I want it to do, but Ive decided to go with modeling the folds in the leather anyhow. What is your problem?



Meaning negative displacement worked without a problem? .....I tried a few times last night after you posted this, and didn't get it to work. I even tried the height map, but the memory consumption on a simple scene was quite a bit more than simply using the more standard displacement in the A&D slot.


I was on a laptop with only 2gb of ram when I was testing negative displacement. Perhaps if I was on a more powerful machine I would not have noticed the extra memory consumption.

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I´m on several powerful rigs, it works ok for know, but send me some grass I can apply on a heavy subdivided mesh with all the shit going on with 150 ies lights/sun/sky/water/underwater-lights/trees etc, and I worship you :)


Yes! I can do, but have no time for rerender of tempered lady behaveior!

Sometime it works!, sometime not.


So, ...does this mean you can render negative displacement? And in a way that is memory efficient?


The questions in this thread dealt with rendering negative displacement, and then I added a question about RAM consumption when rendering negative displacement.


Displacement is a heavy element in itself, and needs to be used wisely. If you have a scene that is as heavy as the one you describe, then it may be wise to do a separate pass for items that need displacement on them. Then composite the passes in post to complete the images.

Edited by Crazy Homeless Guy
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For some reason I've been under the belief that MR uses 50% black as zero 100% black as the maximum negative and 0% black as the max postive displacement. Had the same displacement didn't make any sense till that tid bit came up. I may still be wrong, but the point of the post is to point out that normal mapping can be a useful tool especially in a very poly intense scene. Lots better than bump mapping and if one has to model the creases but still looking for a more effiecient render time ... a thought




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For some reason I've been under the belief that MR uses 50% black as zero 100% black as the maximum negative and 0% black as the max postive displacement.


That's the way I've always understood it for use in MR.


If you're having no luck, you could try a work-around by pre-calculating the displaced mesh, scale it to fit, save the mesh out and use it as a proxy. Might even help with render times too... Just a thought.



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  • 6 months later...

Sorry about bumping this thread from last year - the information here really helped me figure out how to get negative displacement working... But, I found one strange thing that was not mentioned in the previous posts.


I could not get the displacement map under the Mental Ray Connection rollout to do *anything* until I added a blank map into the displacement slot in the Special Purpose Maps rollout... The map can be anything - I used a white 'RGB Tint' map - and then the MR Displacement starts working. I have found this in all old .max files I've opened and in new files.


I have tried this on a coworkers machine and MR displacement works just as described in the posts above - without needing the extra blank map. Does anyone have an idea of what might be changed in my Max install to break this?

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