Normal issues exporting from maya and importing to UDK
polycounter lvl 7
Hi, I think other Polycounters has been circling around this issue but I haven't found anyone that really has nailed the issues I'm having.
I've noticed that when export my meshes from Maya and import my models to UDK the Normal map doesn't display correctly, I have devoted some time to find out where the problem lies. I've made a pretty simple test mesh to trying exporting and importing with different settings.
The mesh displayed in the pics below has all hard edges except the cylindrical objects, they are smoothed. Also pretty much all the faces are on their own seperate UV-Island with a padding of 10 units.
As you can see it looks good in Marmoset, but in UDK the mesh looks pretty harsh and not very smooth. I have exported it as a FBX 2012 file and I have also check the "smoothing group" box in the FBX prompt window. And when I import to UDK I have checked the box for "Explicit Normals".
The thing is that if I export from Max instead of Maya using Smoothing groups my model looks pretty much exactly as it appears in Marmoset.
My big questing is: Is there anyway to get the same result when exporting from Maya as I get when exporting from Max using Smoothing groups?
Maya
Marmoset
UDK
I've noticed that when export my meshes from Maya and import my models to UDK the Normal map doesn't display correctly, I have devoted some time to find out where the problem lies. I've made a pretty simple test mesh to trying exporting and importing with different settings.
The mesh displayed in the pics below has all hard edges except the cylindrical objects, they are smoothed. Also pretty much all the faces are on their own seperate UV-Island with a padding of 10 units.
As you can see it looks good in Marmoset, but in UDK the mesh looks pretty harsh and not very smooth. I have exported it as a FBX 2012 file and I have also check the "smoothing group" box in the FBX prompt window. And when I import to UDK I have checked the box for "Explicit Normals".
The thing is that if I export from Max instead of Maya using Smoothing groups my model looks pretty much exactly as it appears in Marmoset.
My big questing is: Is there anyway to get the same result when exporting from Maya as I get when exporting from Max using Smoothing groups?
Maya
Marmoset
UDK
Replies
Cheers!
this will be impossible to match completely but when exporting out of maya to udk, use fbx and check off export tangents and bi-normals.
and import it into udk with explicit normals checked.
You could try an opposite approach instead of having the edges hard with uv seams, weld your problem edge and make it a soft edge then rebake.
But what do you guys do to get good results with your normal maps in UDK? do you unwrap the mesh into single UV-islands or do you keep bigger island? do you smooth or not smooth?
If you want 'nice' normal maps, what you have now is fine, add in Specular and Diffuse and the issue should be extremely minor. If you want perfection, then go back to the older versions of Max and bake from there, although if going back to a broken and slower baking system of Max to compensate for something else that is broken isn't exactly ideal, so your mileage may vary.
My latest experiment with big UV-chunks and pretty much only one smoothing group for the mesh didn't give a very good result in UDK, worse than the previous version. This is something I've seen before on ze interwebs, the ugly shading you get for having one smoothing group and big combined UV-island instead of seperate ones.
I'm gonna texture some of the models of my main scene now and see how that can improve things. I've read quite bit about this on the internet and I've seen a bunch of pictures describing the issues I've looked in to here. But It is very educating to try out all different setups and see what impact it has.
Thanks for the feedback and info guys.
basically one smoothing group and welded UV-islands = bad result, weird shading
In the pic below we have from left the smoothed low-poly mesh with stitched UV-islands and to the right the hard edge low-poly exported from max. The not so nice looking shading of the smoothed-version is quite apparent, although I like some edges, the light just looks weird on it. And yeah, I made a few tweaks on the smoothed version, I hardened the end cap of the pipes and inverted the Y-axis of the normal map since I forgot it the first time around.
Normal map of the smoothed mesh, with stitched UV-Islands.
All hard edges and exported with 3DSMax using a lot of different smoothing groups
Seeing a lot of gradient and color variation over a surface that should render as flat is called "stressing" your normal map. Because you baked that surface with averaged (or "soft" in Maya terms) normals, to the renderer it's basically a rounded surface. Your normal map then has to compensate and work really hard to fix that surface rounding to make it render flat again.
The solution is to harden the edges. However, when you harden edges you need to separate those edges in the UV map to allow some pixel bleeding, otherwise you'll end up with seams due to texture compression and/or MIP mapping.
If I don't do that I find that what I get is just the opposite of your problem, overly rounded faces. Like I have a two unit bevel on a corner but the normal tries to make the flat face half-round anyway. Aggravating as hell. And I have followed a shit-ton of tutes to no improvement.