What are the best settings for displacement maps in maya arnold

#1

Hi cgers

if i compare a maya arnold zbrush displacement map on lev 1 with settings as below.
the rendered model is fatter than the imported subdivision level 7 from zbrush.

zbrush modelling settings used:
when doing subdivision levels
smt on
suv off
reuv off

zbrush model
multimap export settings:
displacement
flipv
sdiv lev1
smooth uv
adapt off dpsubpix off
smooth uv mid 0
3channel off 32bit exr
scale 1
intensity not sure

maya
arnold settings:

displacement texture map
32 bit exr raw

should alpha is luminence be on
alpha gain 1
alpha offset 0

my tests when alpha is luminence is off
loses fine detail why? or is this need for auto bump.

arnold subdiv
catclark set 3 more sdiv should turn into auto bump
uv smoothing
is it pin corner?
pin border?
linear?
or smooth?

displacement attributes
height 1
bounds padding 0
scalar zero value
auto bump on

(tests show zbrush geo model always exports linear uvs even if subdividing with suv is on,
though off in example used above.)

when arnold saves a tx format does it use the raw srgb, alpha is luminence settings
from the arnold shader map input? ie would a raw exr be converted to srgb?

why if you break the arnold displacement connection, and then try to load another displacement map
it defaults to a bump map?

are these recommended settings?
thx c

#2

This might be a better question to ask in the Maya forum, not the Zbrush one.

#3

Tests show it is the manner zbrush distorts the level 1
model while you sculpt: please see excuse the crap model for test only

grey render using maya level1 no zbrush except imported zbrush maps with arnold displacement settings as given
https://www.flickr.com/photos/93465359@N03/46787274154

green render using imported zbrush level1 with arnold displacement settings as given

zbrush displacement to maya import zbrush lev 1 displaced1024x588

red render using imported zbrush level7 with no displacement

zbrush displacement to maya arnold import zbrush lev7 no displace1024x588

compare shows the maya model would give a bigger displacement if used as level1

zbrush displacement to maya arnold compare1024x588

so if you want accurate displacement you cannot use the model you sent to zbrush at the start.

not sure what the pros do.

#4

Take a look at this tutorial; I found it helped me out quite a lot.

#5

hi

was using that tutorial
and got errors,

in that tutorial they never brought in the hires mesh to compare their displaced renders to it.

the only way they could get that result to match is to bring import the zbrush level 1 mesh
into maya
and displace that

later comments of storing morph target still only work on the zbrush level1 import.
not the original maya mesh sent to zbrush at the start.

do a morph target switch on your modelling at level1 mucks up your sculpt.

to conclude…in pipelines they must do…is this correct?

the only way they could get that result to match is to bring import the zbrush level 1 mesh
and displace that

#6

What sort of errors did you get?

Yes, you should use the level 1 mesh from zbrush and import it into maya. Make sure in the zbrush export settings that “groups” is turned off, unless your mesh is a single polygroup then it should be fine.

One thing that you might want to change from this tutorial, is turning the “Mid” setting to 0 instead of 0.5 and keeping your bounds padding (found under your mesh’s shape node in Maya) to 0 as well.

Be aware that you can also tweak the amount that the maps displace your model, if you’re not getting the exact result you want.