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zbrush maya uv import problem

ZBrush Usage Questions
#1

I made a low poly model in Maya, mapped the uv’s in 0-1 using Pelting Tool 1.5.1, and then exported the .obj to use in Zbrush.

uvmap.jpg

Ignore the fact that I flipped my image. I did that accidentally when shrinking the image for the web.

I think I am correct in assuming that I should see no black in the colored sections. So, my question is why is this happening? Is this a Pelting Tool issue, a Maya issue, or a Zbrush import issue? Or if I did something wrong, what was it?

Any help would be appreciated. I will try to answer any questions to the best of my ability.

Thanks.

bobobobson

Attachments

normalrender.jpg

texturetouv.jpg

#2

There’s nothing wrong with the UV’s. The problem appears to be that your displacement map is an 8-bit image. That always gives the stair-stepping effect that your render shows. You need either 16-bits or 32-bits.

Have you followed the steps in the ZPipeline Guide for Maya? Or are you just winging it?

#3

Thanks. The pipeline certainly helps with displacement maps. However, i was hoping to take advantage of normal maps. I use a mac so there is still no zmapper plugin for my zbrush.

Is there a way in zbrush without the plugin to generate the maps at the right bit depth?

Or do I have import my low and high polys into maya and use surface sampler?

I’ve tried this and the result is what you see above. Perhaps , there is a bit depth setting in maya I m not aware of.

However, I would much prefer to stay in zbrush to achieve these goals.

Any help in either the zbrush or maya side would be appreciated and thanks for the help so far.

#4

Normal maps are 8-bit images. Could you please describe the steps that you’re following to create your normal map?

#5

Several methods tried:

In the zbrush tool menu, I import my .obj from maya. My uv’s are layed out before hand in maya. I draw my mesh on the canvas and enter edit mode. I then store a morph target in the tool menu>morph target. Then, I go to geometry, and I subdivide to about 1,000,000 polys or whatever is necessary for the level of detail. I make whatever sculpting changes i need to on my model at the various levels. I then return to subd level 1 to generate my maps. I go to tool>normalmap and turn on adaptive and tangent and set my map size to 2048. Then I create the map. I then, go to the texture menu select the map, flipit vertically and export as .tif. Then, go to tool>export>, turn on obj and quad poly, turn off texture and group. Export the .obj still at subd level 1. Open maya import the .obj, I just exported, assign a material, apply the normal map to the bump node as tangent, and render.

Also, I have tried to switch the morph target out when in subd level 1, before generating the normal map, but I have noticed that the entire map is blue in those cases with no hint of any other color. I’ve applied these maps to the original mesh in maya and no luck.

Normal map in maya:

I export the high poly mesh from zbrush as an obj, and import it into maya. Both my original mesh and high poly occupy the same space in maya, at the origin 0,0,0. I open modify>surface sampler. I clear the target menu and select my original mesh as the target. i select the high poly as the source. I turn on the normal map, set the size to 2048x2048, set it to tangent, and .iff. Include materials is checked and I set attach to shading network. Under options, i select transfer in world space, medium 4x4, filter size 3, gaussian filter, and fill seams 1. I have not changed the advanced options. Bake and close.

And the results are as you have seen. I have also tried this by importing my low poly .obj that zbrush produced and using the surface sampler with my zbrush .obj as the target. Also, no luck.

I would prefer to stay in zbrush as it is easier to deal with the high poly count there, than to imoprt it into my maya scene and zbrush generates the maps faster.

Hopefully this will help you in assisting me. I really hope I have simply overlooked an option box somewhere.

By the way I always import the .objs with create multiple objects set to false.

#6

Rather than exporting as TIF, try exporting as PSD. There’s no need to use the TIF format for normal maps, since it was really introduced into ZBrush for the capability of exporting 16-bit (and ultimately 32-bit) images from the Alpha palette. For the 8-bit images that are all you can get out of the Texture palette, PSD is perfect.

I’m suspecting the problem might be coming from the fact that you’ve been using TIF for your normal maps.

#7

Unfortunately,psd files did not solve the problem. Any other suggestions?
I 'll keep trying to solve it. It’s worth the time spent for the decrease in render time.

#8

What is the correlation between the rgb for normal maps in zbrush versus maya 7? do I need to flip any of the channels in the preference menu?

#9

Anybody have any ideas?

#10

hey man , im not an expert on normal mapping, only watched a tutorial on it from www.edwin3design.com called zbrush_maya_workflow…think that will help.

as far as file format goes, make sure its not a greyscale image , convert your tiff to RGB in photoshop

Hope that helps