High Rez Lightmaps

[Jerc]

I noticed in the few UT maps shipped with UDK that the lightmaps are very high resolution on the whole level, despite the shadow setting for the BSP for example being set to 32, which should be fairly low resolution.

It looks like the lightmap resolution has been overridden on the whole level.
Is it the case or is there a setting in Lightmass to make the lightmaps super-sharp ?

[Fartuess]

i think it is just part of new lightning system like sharp shadow on surface of static mesh (in older version it was possible, but very problematic)

[Crozz]

You can set both the max lightmap resolution for lightmass and the individual lightmap resolution for each mesh in the static mesh editor, there you could set it as high as you want within sensible limits.

By the way, the BSP resolution setting works opposite of mesh lightmap resolution setting, so the sharpest resolution on BSP is 1, making it not really comparable

[Stardog]

The outdoor directional light seems to cast a different type of sharper shadow than the usual point lights.

[Jerc]

I know all this, the thing is, the static meshes in the maps have a low lightmap resolution setting as well as the BSP.

http://pix.wefrag.com/i/7/c/b/6/a/7708a3f56536d151b192c593dd4dd1a.jpg

Here the satic mesh has a 32*32 lightmap setting, and the lightmap on it has a much higher resolution. I'm wondering how this is achieved.

[Crozz]

Interesting. I tested to rebuild the lighting for that exact object as I lowered the overridden light map resolution, and as expected the shadow definition got more rough, but still looking smooth along the edges. That could be a coincidence though.
Anyway if I remember as I read the lightmass article on udn last night, I think lightmass saves several maps for the consecutive bounces of light (or color or something like that). Those are all probably layered on top of each other to get a better looking effect. Don't quote me on that yet though, it's just what I gathered.
Another contributing yet less interesting factor is that if you look at the mesh's lightmap UV's in the static mesh editor, they are very well unwrapped, wasting almost nothing of the uv space.

[Cr4zy]

I believe it is down to a light called 'DominantDirectionLight' or something along those lines. Have yet to test it myself however.

[Elude]

I believe it is down to a light called 'DominantDirectionLight' or something along those lines. Have yet to test it myself however.

Thats on the right trail, but its really down to the light source radius under lightmass in the dominant light properties.

[ShawnWDP]

It interpolates an edge between the shadow and light of the lightmap. Increasing the lightmap will create more detail in that edge, but the scale of the edge should be pretty constant. Lower resolution lightmaps will create a more "blobby" shadow, but the size of the edge will still be sharp.

[ltrulsse]

I tried experimenting with the dominant light. The thing is, I get really crisp and nice shadows on all my large meshes. On my small meshes, such as fences, the shadows are really bad.

For the shadows to look good, I have to override the lightmap resolution on my terrain to around 64 or 128, and then the build times are either incredibly long, or it crashes.

Any advice here? :)

[Sam2]

I believe the resolution when rendering GI lighting is pre-defined. To make the shadow edges softer all you are doing it changing the penumbras. The way it looks to me is that lightmap resolution is only used for the older direct lighting method.

[Piranhi]

I had a go at recreating the crisp shadows shown above and when using Dominant Directional Lights I found that it gave the crispest shadows but for some reason GI didn't light the way it should have. The room became really dark and it resembled more of a directional light without GI.

Using both a point light and a dominant directional light, in this case, seemed to do the trick though. I got the crisp shadow with the room still been lit enough for my liking.

Before - using just a point light

http://img175.imageshack.us/img175/9325/garage1.jpg

After - Using a point light with a dominant direction light

http://img175.imageshack.us/img175/8161/light2a.jpg

[Elude]

I had a go at recreating the crisp shadows shown above and when using Dominant Directional Lights I found that it gave the crispest shadows but for some reason GI didn't light the way it should have. The room became really dark and it resembled more of a directional light without GI.

Using both a point light and a dominant directional light, in this case, seemed to do the trick though. I got the crisp shadow with the room still been lit enough for my liking.

You can lower the light source radius in your dominant point light lightmass area in your properties to get an even sharper shadow.

[Oblivionbringa]

Dominant lights use a new technique called distance field shadows. This allows them to achieve higher resolution looking shadows even with low resolution shadowmaps.

Before this feature was added, the shadows would have just been box-filtered, so you would have had to use much higher resolution shadowmaps to achieve the kind of results you see now.

[iniside]

I tried experimenting with the dominant light. The thing is, I get really crisp and nice shadows on all my large meshes. On my small meshes, such as fences, the shadows are really bad.

For the shadows to look good, I have to override the lightmap resolution on my terrain to around 64 or 128, and then the build times are either incredibly long, or it crashes.

Any advice here? :)
USe Whole Scene Dynamic Light setting in DominantDirectionalLight You get nice dynamic shadows with GI. Especialy good when you have lots of movable objects on scene (like SpeedTrees). Or just want to screw it, and get nice shadows ;p.