is there any way to blur an HDR env image before the rendering with different values of blurring per object in order to reduce the rendering time? I have been told that there is a special blurring process for hdri images but I don't have more info about this.

If your using the HDR as a reflection map per object you can increase the map's filter per object.

zdimaria
If your using the HDR as a reflection map per object you can increase the map's filter per object.

do you mean the Specular Map Width?

do you mean the Specular Map Width?

No.

If you use an Environment Map Vop for reflections, increasing the Filter Width should blur the map. The different filters will also have different effects. I don't know them by heart but I believe Jeff Wagner has a post about them in his Old School Blog.

zdimaria

do you mean the Specular Map Width?

No.

If you use an Environment Map Vop for reflections, increasing the Filter Width should blur the map. The different filters will also have different effects. I don't know them by heart but I believe Jeff Wagner has a post about them in his Old School Blog.

cheers

Another option would be to blur your map ahead of time, render each object with it's own map and then comp them together after. Not really that special of a process but a blurred map can drastically decrease rendering time.

So you like to convolve your hdri to get a blurry reflection?

There is a convolde note in comp mode that you can use. I have not used this one yet.
Other programs like HDRIshop or Nuke can also convove hdri's.

Then maybe use a ‘envmap’ in your shader and switch between convolve levels (images) after the amount of blur you like.

convolving a image can take time so first scale down your hdri image to about 128x128 if you do a full diffuse convolve. No need for a big image other then for your sharp reflections.


Take a look at this DVD for more info on making fast HDRI shaders

http://www.3dbuzz.com/vbforum/sv_videonav.php?fid=8754903e9ee4d1af8ba1f59c385a3685 [3dbuzz.com]

What is the goal you are trying to achieve? Different dullness per surface? Softer lighting? Depending on what you are using the hdri for, there are different approaches

grayOlorin
What is the goal you are trying to achieve? Different dullness per surface? Softer lighting? Depending on what you are using the hdri for, there are different approaches

Different dullness of reflections per surface.

if that is the case, I highly recommend using the specular angle parameter per surface (in the surfaceModel VOP). I am currently doing something similar and it works out really nice! In my case, I was also able to use a single material with parameter overrides to give each object a different look

that is assuming that you are using your environment HDR as an environment light as well right?