Super bright HDR in skylight doesn't produce superbright light

[soulburn3d]

I believe I already know the answer to this, but I figured I'd check just to be sure. Say I have an hdri that hits at its maximum a brightness of 15 (the sun). And it's been placed in the GI Environment slot (skylight override), and the object in the scene has a color value of 0.5 (50% grey). The resulting rendered image returns values of approx 50-60% grey. Is there a reason it's not returning colors as bright as 7.5? Is it just that the super bright 15 value sun is evening out with its neighboring values in the skylight when its illuminating the diffuse of the object surface?

- Neil

[instinct]

For this to create values as you described the whole hdr would have to be a value of 15. The diffuse value created by a light is dependent on the area. In case of a dome or gi environment this would mean all the parts of the environment visible from a point basically average out. You can try by setting env color to white, turning off the map and setting multiplier to 15. You should pretty much see what you expected.

Regards,
Thorsten

[soulburn3d]

Thanks Thorsten, so it's what I assumed, the super bright sun is being filtered out by neighboring pixels in the env map. Thanks for confirming.

- Neil

[^Lele^]

It's not quite just "filtered" out, Neil, it's properly importance sampled: it will produce sharpish area shadows and area speculars very very efficiently.