Large format printing irr map settings

[stevesideas]

Hello all.

I've recently rendered out a 1920x1080 image for my client using -3,0 in the irr map settings. Now they require a large format print version which I'm rendering out to 10k. What do you think might be suitable settings for the irr map now ? I think I read somewhere that the presets are setup for renders at 640x480 so you have to adjust according to the size of your final output.

Any help appreciated.

[glorybound]

Do you have SolidRocks? If so, use your existing settings in SolidRocks, adjust the resolution, and SolidRocks will adjust everything accordingly.

[Macker]

Pretty sure the irradiance map is independent of the screen resolution - you'll actually be achieving a higher quality irradiance map by increasing the resolution of the image.

The min & max values are how many times the image is downscaled (provided you use negative figures, of course) before taking irradiance samples.

Rendering a 10kx10k image at say -3/-3 VRay will downsample (by half) the resolution 3 times then create the irradiance map, so it actually takes samples from a 1125pixel wide/high image. This is my understanding of it anyway.

Hope this makes some sort of sense?

[stevesideas]

Thanks for the helpers.

I did have solidrocks but I purchased ages ago so not even sure if I'm eligible to upgrade. I didn't use it much to be honest. It didn't seem to produce the quality results I required at the time.

Macker, am I correct in thinking that if you set the irr map to something like min -3 and max -1 vray will use the higher rate of sampling when it needs to for more complex/detailed areas ? Also, would a fully sampled image be more prone to errors than an under sampled image that had a filtered irr map ?

[Macker]

Macker, am I correct in thinking that if you set the irr map to something like min -3 and max -1 vray will use the higher rate of sampling when it needs to for more complex/detailed areas ?

Nope, it will do 3 passes. To control how it works in more detailed areas you will need to adjust the colour/normal thresholds.

Also, would a fully sampled image be more prone to errors than an under sampled image that had a filtered irr map ?

A fully sampled image would be more accurate, generally. There are quite a few different aspects of the irr map that affect quality. You could use a really low min/max rate but really smooth out the result using a larger interpolation, and capturing smaller details with the detail enhance function.

Hope this makes sense, typed it on my phone late at night.