Saving the Importance Sampling Result and EXR

[Ron Martin]

Whatever result the processing (importance sampling) of a Domelight with an associated HDRI produces. It would be nice to have the possibilty to store it for later use.
Also it would be nice to use other HDRI formats with vray too, especially EXR.

[jujubee]

I don't understand your first question. On the second, Vray can use EXR formats.

[dimo]

Hi,

what later use of the importance sampling do you have in mind? There are several ways of doing importance sampling. You can use a Probability Distribution Function that alters the probablility of samples so that the samples occure in the bright areas. Another method would be to threshold the image into regions of similar intensity and then subdivide the regions a number of times proportional to both their size and total energy. These two methods would require different data storage. (I have no idea what the VRay Domelight uses. ) What kind of data do you need? There are several scripts out there that can convert a HDR image into a Light dome where each light resembles the intensity and color of the HDR in this region (e.g. LightGen) . Is this what you need?

Best regards,

Dieter

[Ron Martin]

Well the Vray Dome light does not accept an .exr as input.

I find the importance sampling done by vray very useful and natural looking. Unfortunatly as one is doing several rendertests the sampling has to be done each time again. Would be nice if it could be stored out and reused.

[studioDIM]

as long as you do not multiply it by its alpha (in qhich case it clamps to 1.00 any fp format) combustion can convert your exr images.
A better job is likely done by Fusion, anyways.

As for the importance sampling, it takes very little here with 512 samples taken on a 2k hdr (1-2 seconds...).
maybe for testrenders you can lower the samples to something like 64, which should approximate the hdr nicely enough, and superquickly...

Lele

[vlado]

Well the Vray Dome light does not accept an .exr as input.

Nothing stops you from using the default 3dsmax .exr loader with a standard Bitmap.

Unfortunatly as one is doing several rendertests the sampling has to be done each time again. Would be nice if it could be stored out and reused.

It tends to be somewhat on the slow side, yes. One way to avoid this is to use a lower resolution maps for tests, as the processing time is directly related to the number of pixels in the map.

Best regards,
Vlado

[Ron Martin]

Hi Vlado,

yes, tried it again, standard .exr works. Don't know why it did't the first time.