How to use HDR Cube Map as image-based light

I'm trying to render using an HDR cube map as the light source.  Does anyone 
know how to do this?

I created a skylight and used the cube map as the light color.  My sky is 
blue with a bright sun.  The rendering result is very blue, leading me to 
believe it's using part of the image (otherwise, the bright sun would dominate 
and the result wouldn't be so blue).

Thanks
Doug

Cube as in cross?

You should probably convert that to lat/long, or use teh VRay HDRI loader if 
you're rendering with VRay. Actually I think you might even be able to use 
the VRay HDRI loader from the free version of VRay, as the loader/texture 
itself is renderer-agnostic. 


To make sure your HDRI is being mapped to the environment properly, instance 
it into the environment map slot, too, and see what renders. Unless you've 
made specific provisions for its topological format, it's probably not 
being wrapped properly at all.

Then you have to consider how much of the map is sun and how much is blue sky 
vs sun. Even if the sum total of blue pixels' RGB values is roughly equal 
to the sum total of sunny pixels' RGB values (making the map's average 
colour fairly neutral), the chance of any given GI ray actually hitting the 
sunny spots is vanishingly small, and there are usually only a few dozen such 
rays per sample, so instead of smooth sunlight you'd only get a smattering 
of bright spots.

Generally speaking, HDRI cannot supply decent sunlight. You'll most likely 
need an additional direct light. It's worth noting that any environment map 
(including an LDR snapshot of your HDRI) can be displayed in the viewport, 
so you can look through a camera at [0,0,0] to position a light in the same 
spot as your HDRI's sun.

Thanks.  I'm not using Vray, but your explanation makes sense.  My cube map 
is pooerly suited to be an image-based light.  The sun is a tiny spot in the 
map.  Most rays will miss it.  I'll add a light.

Thanks again
Doug