More on ZBrush NormalMapping...

[tortilla1]

Couple of tests with pics.
Modeled in ZBrush with edgeloops, GUV mapped.
I extract a tangent normal map…I get seams.
First I thought it could be an export problem, or a problem within 3dsmax.
But it’s not. Cause if I extract the tangent normal map in ZBrush and put that texture on the model…the problem is already there. It almost looks like on some
polygongroups, the normalmap changes direction 180degrees (like a negative image)

Are tangent based normal maps rubbish in general (cause I heard about problems with curved surfaces)…Or…is it just not implemented well in ZBrush?

So I tried the Global/Worldspace normal map. No seams here!
Although when I preview that in the Crytek previewer the light consistently seems to come from the bottom.

The lack of response so far is pretty disappointing. I just hope that Pixologic are going to have a closer look at normal mapping before their next upgrade!

Attachments

[system]

unfortunatly i have found the same problem , and just as you no one has said a word .aparently z brush is just unable of doing that right its a shame because it is a really powerful feature, but i think not well implemented. The silence from the people of pixologic just confirms that, and i really hope that they check that out in their next update (or they should release a patch or something beacause is definetly a problem). But at least i think they should say a word on the matter.

[aurick]

We will be saying more – a lot more – in the near future.

[TVeyes]

Many of the normal map renderers/viewers/game engines interpret the RGB channels of a Normal map differently.

For the Crytek engine you need to flip the Green channel of the Normal map. You can do that in Zbrush by adjusting the Preferences > ImportExport settings and calculating the normal map again. You can also do it through photoshop if the model is no longer available to you.

Flipping the green channel is needed for both tangent and world space normal maps. However only the world space normal map will render properly in the Crytek engine. I have not yet figured out what else is needed for tangent space maps.

[system]

wow, that sounds really promising aurick! i cant wait to see the next step in z brush and i really hope tat this application gets better and better

[tortilla1]

Well…I’m looking forward to any improvements in this area!
We got some good results by using the worldspace normalmaps and extracting a tangentspace normalmap in the game-engine (unfortunately I can’t show any pics, cause I have trouble uploading images to the server since a couple of days, no clue as to why).
We need tangentspace normalmaps for animated characters, but we can only use them from ZBrush if we can calculate them in the exact way that ZBrush does.
The quality of the worldspacenormalmaps however could (and should be better), even at a resolution of 2048x2048 they show banding (no smooth transitions between pixels).
Also there should be a feature that allows bleeding of the normalmaps at the UV seams. Because now there still is a (1pixel) seam, and artifacts at the UV seams that I need to fix by hand in photoshop.
I also think Projection Master needs a lot of improvement before it can compete with projection painting tools like Deeppaint or BodyPaint.
We are actually looking into both programs at the moment, and I really can’t recommend ZBrush/projectionmaster for texture painting at the moment, cause there are too many problems with artifacts and seams showing up after picking your model back up off the canvas (especially when parts of the mesh are hidden before dropping).

[aurick]

ZBrush does have a feature for overpainting at the UV seams. After you have finished painting your texture (or creating your normal map), press Tool>Texture>Fix Seams. This will overpaint the borders. There is also a setting to specify how much overpainting you would like.

[tortilla1]

I tried that with the worldspace normalmap that I created.
I extracted 2 normalmaps from the same mesh…one with and one without pressing “fix seams”…I overlayed both textures in photoshop…and they were
exactly the same?!?
3D mesh was UV’d in 3dsmax.

[tortilla1]

Anyway…here’s some positive sounds…and…pics !!!
Realtime character with less then 3000 tris…first pic shows the character textured and lit without any normalmaps…then normalmap, extracted from a high detail mesh created in ZBrush…and finally the result with perpixel lighting. …Good start I think !

[frogspasm]

Hey Tortilla1,

What did you use to extract the normal maps? Looks like they came out pretty well.

~Mike D.

[tortilla1]

Hi,

I used the worldspace (is the default option) normal map button in ZBrush.
Which looks good as long as the object is not animated…

[carthic]

Is there a solution to this yet ? I am having the same problem with normal mapping in tangent space with zbrush. Unfortunately it makes normal maps generation for character game dev impossible with zb.

[frogspasm]

Unfortunately, it seems broken at the moment (this moment being for the last 8 months or so). I’m hoping the 2.5 update gets released at Siggraph next month, but the press release was a bit vague on whether that will happen or not.

I’m really hoping this problem gets fixed then because we’re working on a large project right now that needs this to work. Generating the normal maps in Max would work, but I don’t think I can import a 4 million poly mesh into Max.
Another alternative might be to generate your normal map in Nvidia’s Melody.
It’s a free download of their site, and I’ve heard good things. It’s supposed to be able to handle very large meshes.

~Mike D.

[carthic]

Ach, hopefully we will see the fix update soon then.