UDK Lightmap Resolutions

Progg · Mar 2010

I was always taught to stay low on lightmap resolutions, but this was a very long time ago. I was just curious to see what the industry norm for lightmap resolutions is now-a-days. I usually kept mine under 128px ... is this ridiculous or is this still about right?

SHEPEIRO · Mar 2010

multiple 2k texture set (colour x direction) maps for a level,

a max resolution of maybe 10pixels/metre in the games i worked on, but whatever you can get away with depending on camera view

PixelMasher · Mar 2010

it all depends on the size of the object and style of lighting. overcast type lighting you can get away with a lot smaller lightmaps as opposed to hard cast shadows. On projects ive worked on most objects had 32 or 64 due to being mostly being smaller modular pieces. you really dont need a super high res for things, especially if you have clean/optimized lightmap uvs instead of the auto unwrap like some people do.

SHEPEIRO · Mar 2010

on top of what pixelmasher says about strength of lighting, it also depends if they are stretched to HDR ranges, if they are then rendered AA can be stretched further than 0-1 (0 to 255) making the lit diagonal lines jaggy when viewed from dark areas, increasing the res between these can help. alternatively use soft shadowed lights

tyl3r · Mar 2010

PixelMasher wrote: »

you really dont need a super high res for things, especially if you have clean/optimized lightmap uvs instead of the auto unwrap like some people do.

I'm curious as to what you mean by a clean/optimized lightmap uvs? I've always thought that an autowrap map was the best way to go, and maybe scaling things down so there was a bigger pixel gap between each shell? Can you just explain a bit more perhaps?

PixelMasher · Mar 2010

well you want to stich things together to make the shells as seamless as possible so you dont have a ton of wasted uv space that you get with auto unwrap.

keep everythign unique but get it all into larger chunks, itll help avoid light bleed seams too. you can even stretch uvs a little to fill the gaps better because itll give it more pixel space and minor stetchign doesnt matter, its doing pretty much a render to texture for the lightmap so itll look correct.

gamedev · Mar 2010

With UDK, Lightmass, a dominant directional light and decent lightmap uv's you shouldn't need much more than a 32x32 for each object. The dominant directional light has settings for shadow softness as well that can really sharpen up the quality of your shadows, or soften them for things like sunlight falloff.

3DRyan · Mar 2010

There are a couple things that you can do to get fully optimized lightmaps tyler:

1) Take up as much of the UV space as possible. This ensures that you get the most out of your details at the highest resolution possible.

2) Avoid seams at all cost. It is inevitable that you will have seams in every object, but hide them where the player can't see them. Seams make your lightmaps look like crap. With lightmaps, it's better to have some minor stretching on your texture rather then having ugly visible seams that cut up your lighting.

3) DON'T overlap ANY UV's. This will make parts of your object look incorrectly lit.

Automapped UV's don't take any of this into account. It's always better to do it by hand. I usually start off with an automatic projection, but then I change stuff around to suit the object's needs.

Hope this helps!

Progg · Mar 2010

3DRyan wrote: »

There are a couple things that you can do to get fully optimized lightmaps tyler:

1) Take up as much of the UV space as possible. This ensures that you get the most out of your details at the highest resolution possible.

2) Avoid seams at all cost. It is inevitable that you will have seams in every object, but hide them where the player can't see them. Seams make your lightmaps look like crap. With lightmaps, it's better to have some minor stretching on your texture rather then having ugly visible seams that cut up your lighting.

3) DON'T overlap ANY UV's. This will make parts of your object look incorrectly lit.

Automapped UV's don't take any of this into account. It's always better to do it by hand. I usually start off with an automatic projection, but then I change stuff around to suit the object's needs.

Hope this helps!

Well this is completely different than what I was taught but makes more sense. Everyone always told me to just automap the stuff... but I always found the seams kept forming everywhere doing that. So I should use dominant lights? I was under the impression from the 3DBUZZ videos that dominant lights were really only useful for dynamic objects not staticmeshes.

UDK Lightmap Resolutions

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