[brodie_geers]

I'm confused. When I put an HDRI into the Background slot, with a 1:1 scale the way it gets mapped makes it look REALLY large. Is there a fix for this without changing the scale?

I'm also confused about what the Illumination channel does. I still seem to be getting direct shadows from my physical sun location. So does the HDRI just provide some ambient color to the scene?

[-Adrian]

Convert the 1:1 to 2:1, i don't see any way around this. You can flatten it by mirroring (y scale 2.0) but that won't do you any good if it needs to look good as a background.

Regarding the sun, you need to make sure you set the sky for disabled channels to none. It still might be activated though you use all channels. MXST is funny like that.

[Mihai]

The HDR needs to be in spherical format (lat/long) to work in Maxwell (width twice as large as height). Any other formats (probe, cross) won't map properly when applied to the virtual sphere in Maxwell.

After loading the map in the background channel, click copy to all so Maxwell will use the HDR for all channels. You can disable any of the channels and instead use Physical Sky, Skydome, or None for th disabled channels. The illumination channel will provide all the direct/indirect illumination in the scene. If the Illumination channel is not disabled and you still get direct sunlight from the Physical Sky, set the Use for Disabled to None.