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Zbrush 4 displacement maps not rendering correctly in renderman for maya 3

ZBrush Usage Questions
#1

Hi,

I am trying to render a 32 bit map in renderman for maya 3.

Last time I used renderman for maya it was version 2, and it was with zbrush 2. Setting the alpha gain/offset to 2.2 and -1.1 respectively normally resulted in a hassle free render.

I am using a 4k map, tried both smoothed and unsmoothed. It seems like the problem is associated with differering subdivision algorithms as descrbied here, in the second last post.

Basically it appears that the displacement is not quite occuring in the correct place, so that raised edges for example are slightly offset from the raised part of the base geo.

Has anyone used maps from z4 with renderman for maya 3 and found a workaround?

Any help appreciated,

thanks,

gubar

#2

ZBrush 4 32 bit maps differ from earlier versions. Scott Spencer advises setting the Mid value to 0 , then your alpha gain and offset will be 0 and 1. That’s for Mental Ray but presumably worth trying in Renderman.

#3

Thanks for the tip - that seemd to do the trick, with one difference - putting alpha gain to 1 and alpha offset to 0 (instead of vice-versa) has done the trick.

thanks again

gubar

#4

That’s great, and thanks for giving your solution. :slight_smile: