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displacement map --step by step BASIC workflow?

ZBrush Usage Questions
#1

I have the Z2 manual and have read the online guide and notice that each tutorial seems to have a specific extra step or more (one says you need a plug in, another says you use the cage model, or the morph one etc). One says when you make the disp map in zbrush you crank the DPsubdpix and DPRres values to 4 x 4096 at BESTmode(and I dont see a BEST mode button on either Z2 or Z3 next to the make Dismap button)

another says you convert the tiff you generate from grayscale to an RGB, another says you convert the object to a subd model–another says you use mental ray to render.

Is there a bare bones step by step to making a displacement map from z to maya?

Also–I make a simple sphere model in maya all quads–auto uv map it–then take it to zbrush. and maybe end up with a 100 000 plus object after detailing it. When I get the alpha depth factor its like 1.something

or even 10. something (the tuts I see have a .number, never something with 10. in it

when i try to type that number into the alpha gain in maya
if its 10.4207 it will round it off to 10.421

is this normal?

#2

It is normal. Check for Scott Spencers ZBrush to Maya displacement guide (dont have the link ready). It explains everything in great detail. If you are working in Z3 you’ll have to go through the Alpha depth factor pain.
If you work through that guide you’ll eventually get an understanding of how ZBrush and Maya treat displacement maps differently (took me several times of reading plus respective trial and errors).
Then things make perfect sense.

In Z2, here’s what I do:

  1. Create the displacement map in ZBrush using Multi Displacement 2 using the R32 setting. This produces a 32bit grayscale tiff.

  2. convert that tif into a mental ray .map file typing “imf_copy -p displacement.tif displacement.map” in a dos prompt.

  3. export the lowres mesh from Zbrush, ususlly after calculating the SubD cage.

  4. Import the lowres OBJ and convert it to SubD. SubDs are better for rendering displacement as they are better at adaptively adding mesh detail where needed.

  5. Turn off “Feature Displacement” in the objects attributes.

  6. Create a mental ray SubD approximation for the object by going window>rendering editors>mental ray> MR Approximation editor and hitting create on “Displacement Approx” and “SubD approx” with the object selected.

  7. create a shader and plug a displacement node in it (in the shadinggroop node)

  8. plug a file texture node in the displacement node.

  9. load the .map texture

  10. set alpha offset to -1/2 of the alpha gain (which determines the amount of displacement)

  11. Eventually flip the texture by setting the repeatV to -1

  12. assign the shader

  13. Set to render using mental ray and hit render.

  14. Tweak the approximation parameters to get the best result.

You may need to increase the base mesh resolution if you get weird results.
From my (limited) experience, with a bit of tweaking SubDs will give you the best results.

Good approximation settings are Spatial, min 2 max 5 (# of edges split at rendertime) and a low distance volume (distance for the shortest edge before being divided).

HTH

#3

I am glad its normal!

Thanks for the info

I was reading the scott spencer guide at the wiki.
http://www.zbrush.info/wiki/index.php/ZBrush_To_Maya_Displacement_Guide
So I need MD2

I bought zbrush last april or so and it doesnt have a multi displacement 2 on it. Only Multi displacement.

And I dont see it in my Z3 plug ins either

What’s the alpha depth factor pain in Z3?

#4

Ok I got MD2 now.