Normal Map Issues

Zakk

Hi all,

I'll apologize in advance for the newbie-ish tone of this thread, but i don't have much experience creating normal maps.

I've searched the forums and the wiki for any info, but i find it a bit hard to pinpoint what exactly the problem is.

So, I've made this lowpoly model of a bowl in Max, done a high poly version of it and then used xNormal to create the normal map. (I tried the cage method inside of 3ds Max but it yeilded pretty much the same result.)

Low and High Poly images

Low Polygon
High Polygon 1
High Polygon 2

Now, the problem comes when i bake and apply the normal map (Using either Xoliuls - Which is awesome by the way, or 3pointShader.)

The inner edges of the model looks as good as i could hope, but the outer edges both on the top and bottom the model basically look like shit

Here is the UV and the Normal Map itself:

UV Map
Normal Map

And a wire.

Am I simply overestimating the power of a normal map?

I hope you can help me out, as I'm pretty stumped as to how I'm going to go about this problem.

Spicypixel

May or may not be related but 90 degree angles are pretty bad when trying to smooth them with normal maps. Might be a case of needing more geometry.

Zakk

Spicypixel wrote: »

May or may not be related but 90 degree angles are pretty bad when trying to smooth them with normal maps. Might be a case of needing more geometry.

Yes, thats what I gathered from the various threads on the subject, but chamfering and generally "softening" the geometry, seems to still give me the same - maybe a tiny bit better results.

Jonathan

I do not think your UV islands and smoothing groups are matching, hence the smoothing interpolation problem.

As a side issue, your UVs are laid out a oddly.

Are you aware your smoothing groups and UV islands need to match?

Zakk

Jonathan wrote: »

I do not think your UV islands and smoothing groups are matching, hence the smoothing interpolation problem.

As a side issue, your UVs are laid out a oddly.

Are you aware your smoothing groups and UV islands need to match?

I'm afraid I was not exactly aware of that, no Care to elaborate on that a bit?

And as for the UV's, how would you lay them out? I haven't really unwrapped with normal maps in mind i guess, so i'd be very interested in figuring that out.

Jonathan

Here you go. Where UV islands are "broken" up your model needs to have smoothing groups so the tangent space normal map shows up correctly.

Does that make sense?

I can explain further if need be. (this is just a quick highpoly and low poly, so don't take this as an example how to make an awesome highpoly plate :P )

Zakk

Thanks for taking the time to help me

Seperating the UV islands and seperating the matching smoothing groups certainly helped. The mesh actually looks like the high poly now.

However, now i get some black artifacts on the faces just above the seams (and just above where the smoothing groups seperate).

I've attached a screencap of the edge issue and the new UVs and Normals

Jonathan

I cannot tell 100% from looking at the picture, but it looks as if the lower poly vertex density is too low to cary the high poly silhouette without a few angle/lighting oddities. You may be able to adjust this in Photoshop (be sure to normalize your normal map w/ the Nvidia filter if you do), or perhaps adding extra edge loops will help resolve the issue.

Also, make sure you turn "Edge Padding" up, it will help texture MIPs once in an engine.

Zakk

Alright, i'll try and see what works best.

That being said it's a huge improvement, so thanks again