ZBrushCentral

UV master having visible seams when exporting normal map.

ZBrush Usage Questions
#1

Hi everyone, i have search the forum but couldnt found disscussion on this problem that i encounter.

i am making a strawberry and encounter the following problem.

When i use ‘UV master’ to generate the UV, when i export the normal map and render in maya there is a visible seam. I open the normal map in photoshop and realise that the normal maps’s edge are very hard edge.

But its perfectly fine when i use the usual zbrush way to open uv where the uvs came out with seamles but they are boxes and everywhere.

thanks a bunch in advance to all the kind zbrush pal out there.

#2

images?
normal map?
UV map?
alternate UV map you’re talking about?

#3

thanks goast666 for the speedy reply.

i made a rough shape just to try out this problem.(it happens everytime for me) Steps taken : 1. create base mesh in maya and export. 2. load base mesh in zbrush and click on unwrapped under UVMaster. 3. increase subdiv and start stamping holes on it using alpha brushes. 4. normal map tab : switch on tangent, adaptive and smoothUV. 5. normal map tab : click on create normal map 6. flip V and export normal map (.tif) Here are the imgs:

Attachments

test.jpg

normalMap.jpg

#4

The problem is coming from the use of normal maps and how they are read by a lighting engine.

There will almost always be a seam in a tangent based normal map. You can minimize this by laying out your UV’s to better read and understand the tangents within your map. Basically you need to lay our your Uv regeions by hand to make sure they are supporting left to right (RED), and Up and down (GREEN) channels in how a normal map is being read.

UV master doesn’t support the direct positioning of UVs so you’ll have to use an external UV editor to get the most out of your normal maps.

I hope this helps.

#5

thanks a lot. unfortunately i am weak at technical aspect so actually i still isnt too sure about what is causing the problems and i would like to reconfirm that did you mean lay out UV by hand = open UV the manual way in maya? So it means there arent really any solution for this matter and generating normal map with UVmaster will always give you a visible seam?

thanks a again and could you kindly provide me a link to any articles/writings about tangent based normal map so that i could understand as to how it really works.

:slight_smile: