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Old 01-25-2017, 10:44 AM
Veleno Veleno is offline
WorldViz Team Member
Join Date: Sep 2005
Posts: 148
> What would be the workflow in 3ds max to get the right lightmaps? What would be the best way to change the brightness of the render-to-texture textures in 3ds max?

The cleanest results come from rebaking, but that's way too slow for minor tweaks.

First of all, here's our internal workflow when baking:
  • Get the diffuse textures onto most objects
  • Set up initial lights
  • Do test renders to get a general feel and iterate on the lighting setup
  • Unwrap with Steamroller to UV channel 3. Steamroller is a short script I wrote a while back as an alternative to Render to Texture's auto UV unwrap because RTT's version always insists on grouping UVs by material ID which can waste a ton of space. It also provides quicker access to the function.
  • Make a folder for the bakes. I usually call it "bakes" and stick it in a subfolder of wherever the relevant max file is. This makes it so if I ever grab the project again from our backup system all the assets it depends on come with it. When baking on a render farm I also make sure the bake folder can is accessible by our local network.
  • Bake at low resolution and low quality for very fast bakes, then test out the LQ bake in the scene an iterate as necessary on lighting and initial exposure.
  • When satisfied with the way the lighting interacts with the textures, crank up the settings to your target quality and test them on one object. This may take a while.
  • If the quality seems sufficient on that object, bake the rest.
  • Bakes can take several hours, so consider letting it go overnight or over a weekend. Render farms help a ton, and at the minimum it's very helpful to be rendering on a different machine than your workstation so it doesn't tie up the processing power while you're trying to build more stuff. Render stations can be cheap because they don't require a fancy graphics card to work efficiently - a lot of renderers still don't let the GPU pitch in with the baking process.

Prior to using shader based exposure controls, we'd do minor exposure tweaks in photoshop. We'd make a copy of the baked folder (usually called "bake_mod") to keep the originals intact and run the whole thing though a Photoshop batch process. Anything more than that and you get the same kinds of artifacts you get from trying to do major exposure changes in 8-bit.

I'm going to look into the Vive problem and see if I can reproduce the issue.
  • I'd imagine you're on a fairly modern graphics card, but I'd double-check that the card you have supports 32-bit stuff.
  • Probably goes without saying as well, but make sure all the relevant drivers and software are up to date. I had a different shader issue with the Vive go away on it's own after an update.
  • For very minor adjustments you should be able to get away with exposure the default bit-depth. Dimming usually works better than making things brighter.
  • Since this is a major readjustment it's possible that you may be stuck having to rebake.
  • You can also try using 16-bit to see if that works: vizfx.postprocess.getEffectManager().setPixelForma t(viz.TEX_RGB_16)

Other notes: True GI is super slow to render cleanly, so most of the time I'll fake GI by setting VRayDirt as the intensity of a VRayAmbient Light and supplement it with appropriately placed point lights. If I'm planning to use realtime lights in the scene I'll also use the same approach to provide a base level of ambient light and.

Last edited by Veleno; 01-25-2017 at 10:46 AM.
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