how to render selectively?

[n0ris]

hello
let's say that you have an exterior scene with a building. if you use dome light the glass from the building will highly increase the rendering time.

if i change the glass material to other, simple one, not transparent, render the image with high sample rate from dome light.
then rerender with low sample rate with glass material since you can't see much noise through glass anyway, then compose the 2 renderings. is this a good way of speeding things up?

in other words, how can i keep high sample rates for dome light in order to get nice shadows but also use glass in that scene without huge render times?

thanks

[vlado]

Do you have the "Affect shadows" option for the glass material on?

Best regards,
Vlado

[n0ris]

i am using a material for the glass which i have found on this forum
it's a standard max material with vray reflection map and looks nice

i have tried to use only vray material but i couldn't get it to look like that. so it doesn't have affect shadow checkbox.

anyway i am rendering the GI without the glass since it takes less time and i reuse the solution with the glass on. everything is pretty fast unless i use the dome light and the glass at the same time.

[n0ris]

just an idea: could it be possible to use a map to set the sampling quality?
i mean a gradient map like depthmap to set an interval of sampling qualities in order to adaptively set this parameter while rendering.

you could use higher sampling for detail areas and lower for other.