View Full Version : UDK Material Question
04-25-2010, 09:00 PM
I'm currently diving into my first UDK level with some assets out of Maya. You can see on the mesh that there are some triangles cutting through sections, especially on the top right. This is, of course, after optimizing this in Maya and reducing the polycount (haha) to as low as possible for the asset. No matter how I export the mesh, it seems to always display the mesh in this way. Generally the normal map erases the issue in viewport, but Marmoset does give me similar results when lights are at an extreme angle to the mesh. Any advice of how to rid myself of these display issues?
Attached is a pic of my material network. If you focus on the normal map section, you'll see that I'm using the normal map as a detail map on the back section, a practice I haven't explored before. The normal map itself, however, seems to be very weak overall. I know there's a way to get normal maps to display much better in unreal, I'm looking for some insight or tips anyone may have for getting this thing to pop better.
Note: I created the normal map using Xfer maps in Maya after softening all the normals on my low poly.
04-25-2010, 09:31 PM
Mind if we see the model just in wireframe mode and one just untextured? First guess would be probably needing to go in and soften/harden some of those edges or it might be ngons.
04-25-2010, 09:42 PM
that is a common problem with Unreal. The way to fix it is what we call in 3ds Max- "smoothing groups", pretty much soften the areas as a whole when there is a cut that is going through them. That should fix it, because if you take it into UDK without softening any edges EVEN if they are just a plane...UDK will put its own twist on it and it will give you what you see in your render.
Hopefully this helps :)
04-25-2010, 10:41 PM
Thanks for the quick responses. What you see in the first picture on the post is actually after softening everything before exporting. To be honest, I baked this by softening the entire model before using maya's transfer maps. The resulting normal map looks like what is attached here. My guess is that Maya takes the relationship of the normal map, where it obviously has these triangles defined, and merges it with the soft-edged model, thus nullifying it. Unreal seems to not do this. Here's a shot of the normal map and a shot of the wireframe. http://www.joshrife3d.com/imagehosting/softnormals.jpghttp://www.joshrife3d.com/imagehosting/wireframe.jpg
04-25-2010, 10:54 PM
You should be hardening any edges that have ~90 degree angles. Any edge that is hardened needs to be split in the uv map. So for example the 2 extrusions and the base legs.
All soft will look good in the Maya Viewport in high quality mode, but when you render in mental ray, and in game engines the errors will show up on extreme angles.
04-26-2010, 12:22 AM
Yeah that's what I was afraid of. I'll go ahead and re-bake it with the proper hard/soft edges, thanks for the information there. Any other tips you guys might have on the material setup I have here would be greatly appreciated. Thanks so much for the help thus far. :thumbup:
Just out of curiosity, have you checked how your normal map looks in Maya?
Also you have some very dodgy geometry coming out the top of that inset hole near the top of the barrier. You should change the direction of the edge going left to attach it to the top right instead, and attach the remaining edge to the same side.
Right now that's causing a lot of easily avoidable smoothing issues which certainly won't help your bake.
04-26-2010, 01:25 AM
In maya it looks fine. In Marmoset it looks pretty good too unless i really really skew the light angle.
Here's another issue, probably rooted in the same thing. What I have here is a simple static mesh. I UV'd half, duplicated it over, merged verts at the center etc etc etc. I softened the proper edges, then used axmesh to export to unreal. There I checked the option to export smooth groups.
I've made sure that all my maps tile horizontally, so this can't be a seam rooted in the texture. My thinking is that while there would be some twinning due to the duplicated UV's, the light is obviously getting tripped up there in the center of each cistern and that's based on the mesh somehow. I've tried exporting this with a number of settings and I always get this result. UDK has to support objects with overlapping UV's... right?
04-26-2010, 06:29 AM
@amadreaus: Create a 2nd uvchannel and throw an automap to that one. Its because lightmass doesnt support overlapping UV's in the lightmap.
04-26-2010, 12:17 PM
@haiddasalam - That's a great piece of info to know, thank you!! I overcame the issue by extending my UV's on the object to a 2/1 on the UV, so I just laid out my UV's and extended them horizontally. That seems to be working with lightmass ok.
And the questions keep coming .... :)
As you can see here, I have a spotlightmovable up against the wall, shining down onto the floor. If you look to the right, you'll see what is actually an animating water effect going over the stone with some nifty reflections simulated via some spec/normal maps. However, this effect only seems to show up in what I am calling a 'player light' in my mind; that is to say, you can only see the effect in a certain relation to the character. anywhere in the scene, I can look down and to the side and see the effect, but under direct light influences, it seems to vanish. The same thing is happening with point lights, etc. Is there a way that I can get this effect to show up where there is light... where I'm intending it to pop?
I apologize for the broad range of questions here, I'm just trying to understand as much as I can about the various issues I'm running into. Again, thanks so much for your help and insight, everyone, you're making this a great learning experience for me!!!
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