zbrush exporting displacement problem

DavidVacek

Hi, i usually do not have problems exporting displacement maps, but I've run into strange behavior, but maybe it is me after all...

my base mesh:


my hi mesh:


setup for exporting disp map:

I am using 32bit exr to have full range data to no need for tweaking any values in 3dsmax/vray displacement map.

but I am getting this result after rendering:


When I check displacement map...it looks like it doesn't generate the lowest cavity values...there is just black...even in 32 bit in this areas there is no data...This black corresponds to intersecting areas if I put hipoly mesh over basemesh...and this red areas seen on next image corresponds to missed areas by displacement in renderings...shown on image below... So there is something wrong in exporting map.


I am trying to solve it for couple of hours and I am getting crazy...I tried various setups for export exr/tiff...

Thank you for any help.

David

musashidan

It looks like you need to adjust the texmap min/max. Here's a vid tut I did a while back showing the ZB>Vray process:
https://www.youtube.com/watch?v=hEDL-2v3X1A&list=PLFR9irzqqKRqG8eLxOGYoQDvkpMrOb1P-&index=11

DavidVacek

Thank You for your time and help! Yep it looks like export from zb is ok, I use same setup . The texmap min/max value solved the problem! Nice explanatory tut!

I am used to use displacement texture in material not as modifier. I tried editing the range for exr in output parameters of bitmap map, but it is not working. I assumed that if I am using linear exr file as input for bitmap it uses full range saved in file, automatically -1 to 1.

Is there a way to use linear displacement map in vray correctly by using material displacement setup not the modifier?

also for the size of displacement (Amount value in vraydisp modifier), what if I check relative to bbox  and leave amount to 1 - shouldn't it be then 1:1 size of displacement effect in max to what I have in zbrush?

thanks again!

David

DavidVacek

Ahh ok I messed little bit with the other parameters, the bbox parameter should be off and to use displacement by material just need to check use object mat in vray displacement modifier, so every model i want to use with displacement shouldd have disp modifier and if I want to aply maps etc i just check use object mat in modifier, great!!!

Thank you and have a nice weekend!
cheers

David

musashidan

You're very welcome. Glad it helped. Even though 32bit uses the full range you still need to specify this in the texmap min/max settings.

Also, as the popup box says in the vid, using the 2d option will give you a greater range and more fidelity.