UDK lighting on normal maps

knak47

a simple box with a normal map applied I get horrible lighting seems. only on the back shaded side though, the front looks fine.

I have

separate smoothing groups on each side

plenty of padding on both the Uv channels

All my faces are separate in the UV layout

I have made changes in the UDkEngine.ini file including

I set [FONT=&quot]bUseMaxQualityMode=true and [/FONT][FONT=&quot]bUseTextureStreaming=False
in hopes that this would fix it and it did not.

I have set the light map resolution to something extreme like 256

I have unchecked SRGB in the texture for the normal map and it is also set to TC normalMap for compression.

My normals are fine. They show up great in Max with a 3Point shader and Quality normals on. Also rendered in max they look great. It seams to be a detailed lighting issue. Because when i look at the scene with only detailed lighting that is where you can see those harsh nasty seems.

front is ok

back not ok :poly127:

[/FONT]

sprunghunt

it's caused by your lightmap UV channel combined with the way you've normalmapped and modeled the box.

knak47

Here are the UVs. The box is a primative and the normal map comes from a tessellated and Turbo smoothed version of itself.
How should I be doing it? both channels are unwrapped the same way, I even tried giving the light map more padding than this. Suggestions?

Xendance

Imo the lightmass solver just sucks at this, you'll get best results if you snap the UV verticies on a grid that shares the resolution with your lightmap.

sprunghunt

knak47 wrote: »

Here are the UVs. The box is a primative and the normal map comes from a tessellated and Turbo smoothed version of itself.
How should I be doing it? both channels are unwrapped the same way, I even tried giving the light map more padding than this. Suggestions?
<image>

Every break you put in your UVs will show up as a seam. This is inevitable as the importer will split the vertexes everywhere there's a UV split or a change in normals.

there are only two solutions.

1) split your normals for every split you have in your UVs (this means 'smoothing groups' in max and "hard edges" in maya). This will still give you the hard edge. But at least you'll know it's going to be there.

2) unwrap your box in such a way that it has a minimum of seams. There will still be seams - but less of them. You should still do the technique above as well.

here is epics page about lightmapping:

http://udn.epicgames.com/Three/LightMapUnwrapping.html

The big question though is why are you making a box? If it's just a test then I'd suggest something a bit more complex. Like a crate or a barrel.

knak47

sprunghunt wrote: »

Every break you put in your UVs will show up as a seam. This is inevitable as the importer will split the vertexes everywhere there's a UV split or a change in normals.

there are only two solutions.

1) split your normals for every split you have in your UVs (this means 'smoothing groups' in max and "hard edges" in maya). This will still give you the hard edge. But at least you'll know it's going to be there.

2) unwrap your box in such a way that it has a minimum of seams. There will still be seams - but less of them. You should still do the technique above as well.

here is epics page about lightmapping:

http://udn.epicgames.com/Three/LightMapUnwrapping.html

The big question though is why are you making a box? If it's just a test then I'd suggest something a bit more complex. Like a crate or a barrel.

On UV channel 1 I have the faces split and each face is on a different smoothing group so that the normal map itself has minimal seams. That part is fine

On UV channel 2 I have tried many different unwrappes, all with the same result. I dont believe it has anything to do with how I am modeling or unwrapping the box.

The problem is only on an edge that is facing away from the light. I can rotate the box anyway and the only seam that appears is on the back side where it is recieving inderect light from LightMass.

It is a test and I am using a box because 90 degree angles produce tons of problems if not handled properly as you all know.

Am I missing something?

Gestalt

Are the UV coordinates snapped to the pixels of the resolution of your map? Maybe one of the islands is flipped? Also is there a reason you're using a normal map for the box?

knak47

I will check if one of the islands is flipped I hadent thought of that. How do I go about snapping the islands to a grid?

And the box with the normal map is just a test like I said to work out lighting issues.

odd_enough

There also something to note about lightmap seams, as it is something I got hung up on for the longest time. Until you get your object fully textured, it's best not to worry about the glaring lightmap seams you might get. So matter what object you make, the seams will always look bad with a solid color.

When I was first figuring out lightmaps, I let my perfectionist tendencies kick in and I would obsess over these seams for hours. It wasn't until I gave up and textured the model that I realized that seams are unavoidable. Even the assets made by Epic that come with UDK have them, you just don't notice them because the textures tend to cover them up. The more busy the texture and higher in contrast, the more they blend in.

If you still feel the seams are glaringly bad after the asset has been fully textured, then you might need to learn best practices for lightmapping.

Gestalt

I do my UVs in Blender which lets you select a texture resolution and snap to those pixels. It also lets you type in specific coordinates for points. I haven't done my UVs in this type of depth with other programs so I can't help you there. Lately I've been trying to keep all my UVs snapped if I can, even for my other maps because it keeps things clean and consistent. For lightmass UVs layout and snapping is very important. http://youtu.be/ntx10JMl9f4