Exporting an HDRI map fro Vray

[J_Bug]

If you're using MAX6...

1)Enable the Unclamped color G-Buffer

2)Render and save the image via Save File dialogue window (don't save from the VFB)

3)Make sure to set the file as Radiance Image File and use Real Pixel data.

That's all

For other versions of MAX you'll want to download the Splutterfish HDRI I/O plugin.

The problem I was having was at step 2. I've found for best results you should also render with a Box type camera which makes the file very easy to manipulate and reuse in VRay. Don't forget to use a 3 to 4 aspect ratio so the box will unwrap undistorted.

--Jon

[DaForce]

Ok, i see what you mean now.

Its still just doesnt sit right with me tho....dont know why but it just doesnt.

Time for me to go test a few things out me thinks

Would it make sense if i said that the HDRI's that you download which are made from LDR images like debevec's ones have a more noticable and real affect then the ones that Vray will make??

In my mind, if you were to recreate the kitchen HDRI scene in Vray, doing a HDRI the way you mentioned would not get the same results as doing 20 different renders with different exposures and putting them all together in HDRshop...correct?

Because as things go brighter the lighting would change significantly, and how can vray know just how the lighting will react without tracing all the light at the higher intensities, is it like a guess or something (in basic terms), or does it just take the current light levels and increase them (hence the need for unclamped color) for me that seems odd.

Or, am i just looking in to this too much, and they are really 2 different types on HDRI and should be treated differently?!?!

[trixian]

... and how can vray know just how the lighting will react without tracing all the light at the higher intensities, is it like a guess or something (in basic terms), or does it just take the current light levels and increase them (hence the need for unclamped color) for me that seems odd.

Ah...but here you assume that Vray calculates everything in 8 bits per channel internaly. Even max scanline calculates in 64 bits internally. Most likely vray does the same or similar.
Anyway, as mentioned, using high multipliers and colour mapping, you allready have the range set to more than the normalized 0 to 1 intensity of pixel values.
The main reason most rendered hdris don't look as good as say debevecs hdr images, is most likely from the mere fact that they are photographs, and contain all the correct effects that happen in real life as light intensity increases / decreases, and no renderer can, as of yet, produce the same results.