What's causing this artifacting?

danshewan

Hey guys,

So I'm tightening up some assets for the scene I'm working on, and I've encountered a normal map problem (gasp!) that I've not seen before. I'm using Max 2009's render to texture function.





Quite simply, what's causing this weird bitty artifacting?

I've tweaked the low-poly geometry to match the high-poly as closely as possible, the cage is hugging the geometry as closely as possible, and there's no overlapping UV's. The UV shells are broken according to smoothing groups and hard angles and there's a lot of sections that needed to be separated into strips, which is why there are so many individual rectangular shells.

The map as generated by Max's render-to-texture:





and xNormal:





So, is my UV layout to blame? Or a geometry problem? Or fate conspiring against me so that I never finish my scene....?

Thanks in advance for any suggestions and / or light-hearted mockery.

Farfarer

All the bitty stuff looks like standard edge padding. Just that the edges are beveled and so it's grabbing a fairly extreme normal angle to pad with.

The fact it's so blue in the main areas leads me to believe there's not much extra detail that needs to be added with the normal map - mostly just beveled edges. The low and high poly meshes are pretty similar.

danshewan

Thanks, Talon. And yeah, there isn't much difference between the high and low, so I think I'll just bevel the edges and apply a normal map for some high-frequency surface detail.

Thanks again.

Noors

looks to me that rays are too short. What if you increase the maximum frontal ray distance in xnview ?
http://www.xnormal.net/Tutorials.aspx
In max rtt, in projection options there's a ray miss color checkbox to display missed part on render. I don't know how to increase ray distance in max though.I usualy scale models/edit the cage.

danshewan

Noors wrote: »

looks to me that rays are too short. What if you increase the maximum frontal ray distance in xnview ?
http://www.xnormal.net/Tutorials.aspx
In max rtt, in projection options there's a ray miss color checkbox to display missed part on render. I don't know how to increase ray distance in max though.I usualy scale models/edit the cage.

Hmm, hadn't thought about that to be honest, Noors. I'll play around with the settings before adding bevels, see if that improves the result.

Eric Chadwick

Are you using Supersampling? I found the edge padding in RTT to really suck when I also use supersampling. In which case I do the edge padding afterwards in Photoshop.

danshewan

Eric Chadwick wrote: »

Are you using Supersampling? I found the edge padding in RTT to really suck when I also use supersampling. In which case I do the edge padding afterwards in Photoshop.

Well, I was using the 2.5 Star supersampler, but disabling it has no discernible effect on the resulting map whatsoever. I'll bear that in mind for future reference, though, cheers Eric.

Even though there's not much difference between the high and low, I'd really rather figure this out than bevel the edges, as the count is already a little indulgent anyway in an effort to match the high-poly more closely and chamfering all the necessary edges is going to push the count much higher - any other suggestions?

Eric Chadwick

Well, how does it look when applied on the model? Artifacting in the texture doesn't matter, as long as the lighting is correct in-game.

danshewan

Eric Chadwick wrote: »

Well, how does it look when applied on the model? Artifacting in the texture doesn't matter, as long as the lighting is correct in-game.

Here's a Max grab, using Xoliul's shader with just the normal map applied:






And how it looks in the scene, with placeholder diffuse and spec (brightened in Photoshop, because all my screengrabs come out much darker than they actually are):

Eric Chadwick

Yeah so there are a few artifacts on the gray viewport model, but I can't see them at all in-game. Unless they're really obvious in-game, I'd take a pass, concentrate on more important stuff.

Plus, your errors are probably more to do with the angle of the baking rays, and not to do with the padding.