View Full Version : Baking light and having it interact properly with unbaked lighting

Captain Obvious
10-25-2007, 05:09 AM
So, I'm having a bit of an issue with Lightwave... I've got a bunch of office buildings with interior lighting (it's a dusk shot). I would like to bake said interior lighting into an image map, to speed things up, but bake ONLY the interior lights and keep the interaction with exterior lighting (skylight, mostly).

If I bake it to a color map and make it luminous, I lose the interaction.

If I bake it to a color map and make it luminous AND diffuse, I get inaccurate (read: crummy) results.

If I bake it to a luminosity map, I lose the color of the interior lighting.

In many applications, there's a separate channel for light maps, that basically just add image-based diffuse non-directional illumination, but Lightwave does not have this, as far as I know. In modo, the luminosity has its own color channel.

Does anyone know of a good solution for this? A nodal solution would work, too.

Thanks in advance!

Captain Obvious
10-25-2007, 05:17 AM
Rendering in FPrime, by the way!

10-25-2007, 09:51 AM
Isn't the fact you're using luminosity what's distorting things? If the map is lit like an interior, what about just using a high diffuse value (100% or more) on the baked surfaces.

You could vary the amount of glass transparency to control the amount of external light getting in.

10-25-2007, 03:05 PM
I hope you were texturing in the node editor...

Loading the baked light image into a node and adding (Vector Add, or use a Mixer node set to additive mode) it to whatever your old Diffuse Shading input was will create the effect you're looking for.

If your surfaces were set up in the classic surface editor, it could still be easy if one of the main categories of shading (Diffuse, Specular, Reflection) was unused. Load the image into a node and just attach it to one of those Shading inputs (if you use Reflection, the reflection amount will need to be set to 100% in the classic surface editor.)

Otherwise, you'll need to port one of those channels of each surface into the node editor so you can add the baked lighting to it, and then plug that sum back in.