View Full Version : light map problem


ghostlake114
05 May 2007, 05:14 PM
Right, I know It s difficult to discribe. But let s go

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First, I have bake a texture like this

http://i35.photobucket.com/albums/d152/ghostlake114/Box93CompleteMap.jpg

It seem good, but I want to archive the same effect with Layer texture and Multiply blending

===

I create some thing lightmap from the render

http://i35.photobucket.com/albums/d152/ghostlake114/Box93LightingMap.jpg

and this is the tiling texture I want the light map texture to blend

http://i35.photobucket.com/albums/d152/ghostlake114/brick03-1.jpg

The result of multiply blending, white poor image

http://i35.photobucket.com/albums/d152/ghostlake114/multipol.jpg

The reason is when using multiply. the base texture is brick and the brightness we could see is the base texture.
So, are there any way to use lightmap with intensity plus to the base texture. I guess that we must render out a seperate "intensity map" and aply a onther blending mode to the base texture, but can not figure out...

Mr. D
05 May 2007, 05:32 PM
Hello

lightmap as you know is a blend map, where white causes you diffuse texture to show at full value (the actual color of the bitmap), with the color being darkened by the more grey/black you go.
A diffuse texture will not go any brighter than then level it is (unless added lighting effects in scene).
so for you images best suggest drag the lightmap into a paint program and play with the contrast/brightness. since your diffuse brick can not be brighter than how it is try brightening it up.

Mr. D

Rens
05 May 2007, 06:33 PM
First of all the light map you're showing is completely blown out, so all that white area will have the same colour anyway.

A way to not have it blown out and have your texture displayed somewhat correct is to lower the intensity of all you lights together (scale it down) so that the brightest point just reaches full white, then render out that map.
Then in your compositing program drop on the texture and set the texture to multiply, then scale the resulting image back up. In Photoshop you would use the 'input white' slider in Levels, just drag it to the left until you're happy.
Use either an adjustment layer or work with a merged layer.
This work really nice and is probably your best bet.

Another option is to work with high range images such as HDR or EXR if you programs can handle those.

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05 May 2007, 06:33 PM
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