Rendering Displacement maps from zbrush 3.5 in Mental Ray


#1

Hey guys,

I’m having alot of trouble trying to render displacement maps in mental ray from zb 3.5.

My model keeps ballooning out no matter what scale i have and settings i use.

So i was wondering what steps are needed to be taken from zbrush to mental ray to successfully render displacement maps ?


#2

look at this tutorial: http://www.neilblevins.com/cg_education/mudbox_2009_to_max/mudbox_2009_to_max.htm#DisplaceModifier it’s by neil blevins and really good. Takes you through all the steps involved from mudbox to max. Same techniques apply to zbrush, of course.

David


#3

Check this out - it’s for Mudbox but very relevant to ZB

http://www.neilblevins.com/cg_education/mudbox_2009_to_max/mudbox_2009_to_max.htm

There are a number of reasons that your model will balloon but without knowing how the displacement settings from ZB etc and the settings in Max v. hard to tell.


#4

cheers guys :slight_smile:


#5

I’m struggling with this as well so sorry for reactivating this thread (was it solved for you Kravit?).

Anyway the guide by Neil Blevins is very informative, but Zbrush doesn’t provide a straightforward value for search-distance / displacement amount.

Any more experience on this? Anyone got this to work?


#6

Depends what you are using, Height map or just the your Blinn displacement slot ?

   I'm pretty sure you will get some different results with the two, i never did anymore testing with it since i just decimated my models instead.

(Edit) Remember what i was doing wrong now, just need to set your RBG offset to -0.5 in your material setting.

32 bit displacement wont need this.


#7

So settings you need to use with height map is

Height map settings -

Min height : 0
Max height : 1-1.3

Don’t use global settings for displacement, better to use the settings under the object properties for the mesh your applying the displacement too.
I find you can get exact settings you need using max settings instead of 1k crap under global, they are usually in between the settings you actually need, so usually bogs down your renders with pointless subd to your mesh.

Displacement settings-

edge length : 0.1
Max displace :1

Max levels : 3 for just tweaking lighting etc, so you don’t waste time rendering, then for final renders I use 5-6 max levels.


#8

So you are now working with 32 bit maps right? Tiff or EXR?

What do you mean by “decimated the models”? Importing optimized OBJ into max and RTT from there? I tried that as well but one of the sculpts I have intersects itself, which means the max’ way of projection doesn’t work well for me (UV match = unclean result, cage = I get unwanted projections from other parts).

Here’s my situation:
I need to blend between different maps (animated sofa wrinkles), and the Composite Map doesn’t seem to work properly with in the Arch & Design Displacement slot.

Plus, Composite with multiple 32 bit maps bogs down my Max, so I fall back to 16 bit maps.

I ended up using the Displace modifier, for the strength I use Alpha Depth Factor * Mesh Scale in Zbrush/Tool/Export. It seems to be about right but not 100%.

So I’m still looking for the right way to determine the displace amount. Why this pipeline still doesn’t have a tried and proven, fool-proof tutorial (for max) is beyond me.

Nice tip regarding the local subdiv setting!


#9

So you cant just generate a disp. map in Zbrush and then apply it on your model in MAx?


#10

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