Bake Image Based Lighting

McBradd

I'm trying to figure out the best way to bake lighting info from an HDRI into lightmaps.

Specifically, our pipeline is designed so that you light your scene using Point lights and Area Lights in Maya, Create a second UV channel for everything, then run a script that bakes the lighting info down to lightmaps, and creates light probes for the interactive objects.

Is there a way to sample the lighting values that would be present at the location of each light, so that when they are baked down it produces similar results to the
HDRI?

cman2k

I'm guessing you essentially want to capture very low resolution cubemaps?

McBradd

Naw, We've got tools to capture nice cube maps... I have a pretty nice library of HDRI's, and I'm trying to figure out a way to iterate on the lighting in a scene quickly, just to try out different times of day, and play with the mood set by the lighting.

I'm basically trying to adapt the techniques I've used in the past for static renders to realtime.

Noors

Bake to 32 bits lightmaps (.exr, tiff) ?
Didn't experiment this myself but Ali Rahimi Shahmirzadi made some demos and shared infos on quest 3d forums
http://forum.quest3d.com/index.php?topic=63520.0
http://www.ali-rahimi.net/pages/portfolio.html

EarthQuake

You just want your ambient lighting to contribute to your radiosity? In modo you can use a "photometric" light, which is just loading a HDR cubemap for lighting contribution, I would look into something similar.

Stromberg90

I think he is talking about doing it in a game engine, so that non static objects gets lit the right way... I might be wrong.
Cause if it was a offline engine you would just render with a hdri environment.

EarthQuake

I'm trying to figure out the best way to bake lighting info from an HDRI into lightmaps.

Would suggest that he wants the HDRI content to affect the lightmap bake. Unless his statement here is totally wrong?

I'm basically trying to adapt the techniques I've used in the past for static renders to realtime.

But then there is this, which is sort of the opposite. I'm confused now.

What is it that you want to do, exactly?

Bake ambient lighting into your radiosity(lightmaps)?
Use an HDR cubemap for ambient light in your engine?
Something else entirely?

Noors

I think he wants lightmaps and play with exposition, which sounded like 32 bits lightmaps to me. idno
Look at turtle render to ease the process in maya, cool tool.