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ZB4 Normal map problem - please help!

ZBrush Usage Questions
#1

Hi all

Struggling with a normal map problem here. I’ve attached a ZBrush 4 .ztl and .obj so you can have a go with it too…

Here’s a very simple piece of geo. It has clean UVs, and was originally made in 3dsmax 2010 and exported to obj without normal or smoothing group info (although in our tests adding in either of those doesn’t make any difference).

I subdivide it to level 5, with SUV turned off - it’s for a game model so I don’t want to smooth UVs at any point. I sculpt, then return back to L1 and bake a normal map.

In the normal map bake settings :

  • Tangent is ON. If tangent is OFF, the world/object space normal map works perfectly. I need a tangent space map, however.
  • Adaptive is OFF, and doesn’t solve the problem if it’s ON
  • SmoothUV is OFF. If I turn it ON, the problem goes away, but then my UV island is smoothed and thus totally useless for my not-to-be subdivided model

Here is the problem :

Example.jpg

The image on the right shows the wires, the image to the left shows the baked normal map applied as a texture (with a white material).

Here are the files :

Example.zip

So - any idea why the normal map is so broken? What am I doing wrong?

Help!

#2

I run into this problem all the time if I use zBrush to generate normal maps. I think it may be an issue of the geo not being closed, like a sphere or cube would be. Try creasing the edges. If that doesn’t work then just use xnormal. Its free and works perfectly. Though the exporting can be tiresome.

#3

Thanks rissta - well I’m glad to hear it’s not just me!

I love XNormal, but as you say it’s tiresome when you have a whole bunch of tools and groups to bake separately, and there’s the degree of guesswork involved in ray distances etc.

This is a really, really simple case for ZBrush - I can’t understand why it doesn’t work, which is why I was wondering if there was anything I should be doing to avoid it…

#4

…especially as the non-tangent space bake works perfectly!

#5

it looks like you might be having the same problem I was having over in this thread
http://www.zbrushcentral.com/showthread.php?t=97299
I managed to find a solution, which I posted in that thread, basically it’s something weird 3dsmax does to the UVs of it’s objs.

#6

Thanks Artesia, but unfortunately it’s not that issue. This occurs for geo created entirely without max, and mapped with UV Master.

Although, the spinning-UVs-from-max thing is also something I’ve come to know and love intimately!

Anyone from Pixo fancy explaining what’s going on with my problem? Why it just doesn’t work? And if there’s anything I can do about it?

#7

BUMP

Pixo?

#8

I was experiencing this too. I’m fairly new to ZBrush. (And Digital sculpting in general. Have used MudBox since March.) Anyway I was having this problem to until I turned on smooth UVs in Zbrush. It’s true it does shift the internal UVs a little, but for this character I’m not worried.
However on the down side there are some edges that did get smoothed so this texture is unusable.

<br><br> Acctually, I experienced something like this in MB and my solution was to smooth UVs on my actual model and then sculpt and export. Sometimes the UVs on your model are too sharp and the software just sees sharp corners like this... That's the only thing I could conclude. So if you want your maps to export with no hard corners, make sure your UV don't have any hard corners either.

In Zbrush try keeping the “SUV” button checked when you divide geometry. this will smooth the internal UVs of your model as you go up in detail.

Attachments

shoulder_noPinch.jpg

#9

if ZMapper is only available.