Wavy Normal Maps

LRoy

I'm not sure why I didn't run into this problem with the first part of my mesh, but I'm getting wavy normal maps when I bake out my textures. I'm thinking it has something to do with the fact that I'm squaring off the UVs now. Is it best to leave the borders with their natural curve or is there a way to avoid this?

Here's some of my test renders to give you an idea of what I mean.

ZacD

show us the uv's and the models with wires.

keres

Your cage is more than likely all screwed up. If your cage is not perfect, it can easily do this. I encounter such a problem when baking cylindrical meshes quite often.

What program are you using?

Mark Dygert

Yep, what app? What does your cage look like if you're using one? Try turning down the ray projection distance if you're not using a cage.

Also... it never hurts to check the wiki...
http://wiki.polycount.com/NormalMap?highlight=%28\bCategoryTexturing\b%29#Solving_Wavy_Lines

EarthQuake

Wavyness is generally irrelevant to ray distance, it is ray *direction*, not distance that causes wavyness.

There are basically two causes to this sort of thing;
1. The difference between the high and low is too large, this means that your high is very smooth but your low is very jagged, thus, when the rays are cast out at an angle(because the rays are based on the mesh's averaged normals, they do not shoot straight out) you get these wavy areas.

2. Similar to the above, the normals of the low are too extreme, so your projection is shooting out at a 45 degree angle, and exaggerating the difference.

A "bad cage" is almost never the cause of this.

Now, you can tweak the cage, in certain apps, but this will not actually solve the problem, just massage it a little bit. You're treating the symptom and not the problem with the cage tweak workflow, not to mention that its annoying to do, and you have to redo it any time you change your mesh. In addition, it only works in certain apps like Max, maybe Xnormal? It does not work in maya, as editing the cage/envelope only adjust distance, not normal direction.


So, with that in mind, the best thing to do is:
A. Add more geometry so that the low matches up more accurately with the high, people really fail to realize just how many problems are caused by the low not being accurate to the high.

B. Add more geometry so that you soften the normals of the low, or modify the low so you have less steep angles near the problem area.

Generally I like to do A, because it results in a better overall model.


Now having said all of this, what is important is how the result looks *on the model* and some wavyness can actually improve the look, atleast from certain viewing angles. So you should post a screenshot of the map applied to your model, along with wires of your lowpoly.