{"id":656,"date":"2013-05-06T03:50:22","date_gmt":"2013-05-06T10:50:22","guid":{"rendered":"https:\/\/williamgs.com\/wp_backup\/blog\/?p=656"},"modified":"2019-06-11T16:55:39","modified_gmt":"2019-06-11T23:55:39","slug":"natural-history-lightmap-test","status":"publish","type":"post","link":"https:\/\/williamgs.com\/wp_backup\/posts\/natural-history-lightmap-test\/","title":{"rendered":"Natural History: Lightmap Test"},"content":{"rendered":"

\"demo<\/a>
demo screenshot<\/figcaption><\/figure>
\n
\nThis post will be a long one, so I wont get it all at once…updates to come.<\/p>\n

First off— so I wanted to create a test environment with lightmaps. I downloaded the Natural History Museum model from 3dRender.com to start, and the laid out the UVs in a reasonable manner. At first I thought I could get away with one or two maps, but there is just way too much surface area for the quality I wanted to achieve, and so came 23 UV maps.<\/p>\n

Next I got a reasonable balance of lighting that I was looking for. Based on Mental Ray’s physical sun & sky system, with portal lights for all the main windows, I did a sort of quick set up.
\nNow in traditional rendering, separate passes for direct and indirect are no problem. I wanted that, but also to have separate passes for each main light source. Ideally, the renderer should spit this all out without much trouble, but this is Maya\/Mental Ray, so it wasn’t going to be easy. Additionally, I wanted to bake this all to lightmaps (for real-time rendering later). Rendering Direct\/Indirect is simple enough, but the remaining problem here was twofold:<\/p>\n

    \n
  1. Rendering separate passes for each main lightsource (Sun, Sky, artificial)<\/li>\n
  2. lightmaps dont allow membership or layer overrides.<\/li>\n<\/ol>\n

    \"Natural<\/a><\/p>\n

    Although lightmap sets are a special form of object sets, they’re extremely limited. I wanted to avoid creating 7 of separate scenes every time I wanted to render ( since I had 3 light sources, direct and indirect for each, and alpha). For this I created a MEL script node… (explanation to come)<\/p>\n

    So I got something like this (top center and top-right are composite maps):<\/p>\n

    \"Lighting<\/a>
    Lighting \/ Render Passes<\/figcaption><\/figure>\n

    After balancing the passes in Nuke, here’s a few screenshots of the results back in the maya viewport:<\/p>\n