Author Topic: Light maps? HDRi?  (Read 4331 times)

Pete Stoppel

    Reputation: 33
Light maps? HDRi?
« on: May 18, 2011, 06:27:50 pm »
May 18, 2011, 06:27:50 pm
I watched the material tutorial again as I want to use an hdri for lighting, but I cannot make heads or tails from the tutorial on how to use it, it does not say how to import a light map, just that a model with a light map can be imported. So say I'm using Sketchup, how do I export it with a lightmap?

Does Lumion support HDRi? how about Equirectangular jpg's?

Please let me know how I can use my own skys/panoramas.


Re: Light maps? HDRi?
« Reply #1 on: May 18, 2011, 08:31:16 pm »
May 18, 2011, 08:31:16 pm
You can map dds hdr files to a Box or shere but I'm not sure what will happen with the shadow. Obvioussly you don't want your sky cube to cast shadows. Maybe we should make it a dedicated function so you can replace the sky with your own cube an Lumion will also use it for ambient lighting.

Michael Betke

    Reputation: 35
Re: Light maps? HDRi?
« Reply #2 on: May 19, 2011, 09:21:32 am »
May 19, 2011, 09:21:32 am
Plus having it for the complete lighing would be great. Autodesk SHowcase features this kind of lighting. I just put my HDR image into the slot and the scene gets lightend in real-time.

Couldn't Lumion just calculate theaverage color for the HRD image and use it as ambient color plus the brightest (radial) spot on it as the sun position and the color of the spot as sun color??

Re: Light maps? HDRi?
« Reply #3 on: May 19, 2011, 10:12:33 am »
May 19, 2011, 10:12:33 am
Plus having it for the complete lighing would be great. Autodesk SHowcase features this kind of lighting. I just put my HDR image into the slot and the scene gets lightend in real-time.

Couldn't Lumion just calculate theaverage color for the HRD image and use it as ambient color plus the brightest (radial) spot on it as the sun position and the color of the spot as sun color??


That's what we currently do with the sky. We use the sky cube map to generate an irradiance cube for lighting.

When would implement a HDRi cube map function we need to replace this function though because converting the sky cube map to lighting map assumes the sky is low frequency and a custom cube map might have really bright spots in it so it does not work.

We had a problem before with this when we also calculated the sunlight in the irradiance map so now they are calculated separate from each other.


The lack of resolution is easy to fix by using a more complicated formula to integrate the cube map but it's slower. Currently the irradiance map formula is almost instant so that's why we use our current solution.

In theory it's easy to fix though. We did not build in a cube map function to begin with because we thought that only very skilled professionals would be able to create HDRi cube maps. It might be a bit to complicated for Lumion. Maybe the feature will reappear in later update as a function "under the ctrl key".