3D MAX. How to render without lights but with light map!
Hi everybody!
I need to render the scene using the light map as the lighting. I've baked the light map but I can't apply it! My attempt to use it through the self illumination has failed. It gives black/white lighting. There is no color information of lighting. Please help!!! Any advice?
I need to render the scene using the light map as the lighting. I've baked the light map but I can't apply it! My attempt to use it through the self illumination has failed. It gives black/white lighting. There is no color information of lighting. Please help!!! Any advice?
Replies
There really shouldn't be any color information within your lightmap. Self-Illumination is the right direction. How did you UV all the meshes for your lightmap? Make sure you have the correct UV map specified in the parameters of the material you plug into the self-illumination.
Where on earth did you hear that? Lightmaps should allways contain colour information.
A nice way to do it in max is to put your map in the self illumation slot, turn on 'Color' under the 'self illumation group' in 'basic blinn parameters'
to setup the map create RGB multiply node and multiply the lightmap by the diffuse map. You will probably want to increase the output amount of the bitmap to about 2 or 4 to get nice results.. presuming your not using a HDR
Personally I'd use mental ray for it. Set your FG to low/Medium, turn off noise reduction and set the diffuse bounces between 2-5 (depending on your scene.)
Flatiron is a good tool, but I don't let it decide how to split up my scene into different lightmaps. I make several large objects that are composed of many attached objects. I use flatiron to unwrap these, usually iteratively until I get good results. I hand-massage the UVs a bit if necessary, and I use render-to-texture to bake out my maps.
Flatiron is a pos in my opinion. It's fast but sloppy as hell. I need to do the entire scene into a 512*512 lightmap and I'm having a rough time working on a good workflow. I came across a workflow on the web that explained to combine the entire scene into one piece of geometry, automapping it, and using Render to Texture to bake out the lightmap as you explained. My question on this is, how could you reapply the materials (with the newly created lightmap in the self-illumination slot) to each object individually after I've combined it all?
I'm a Maya user, so I'm really trying to get 3DS under my belt, but It seems like there would have to be a better workflow than what I found.
By using a 2nd UV channel, you should not have to change your materials or their application at all. The 2nd UV channel is what will get 'automapped' and Render-to-textured, and it will only hold the lighting information.
If so, I think you may need to make sure you are storing your lightmaps in a 32-bit format so you get a wider range of possible values...? I'm not too sure, I don't deal with rendering and 32-bit stuff often.
If not, and this is for an engine of some kind, then you need to figure out how you will deal with exposure and stuff. 16-bit textures are inherently going to be limited to a limited range of values. If you have lights that go beyond those values, they won't translate into a texture well. Some people render their lightmaps out in a purposely underexposed way, then overexpose them in their engine using shaders and whatnot.