Helping out Iray "architectural renders", any tips?

evilded777

So the Architectural sampler is supposed to help when you have light from a window as your primary source of illumination in a scene.

Does it actually help? My experience is mixed.

Who has any tips for helping these renders along? Any tricks for speeding it up, getting better convergence quicker? Anything?

 

Seems like I do a lot of these types of renders and end up waiting over night or so for the environment part of the image to render to a useful state.

Tobor

It helps but is not an end-all solution. Iray has another light helper for this situation, called a sky portal, but D|S does not (yet) support it. If and until then, you'll have to play around with other light sources and adjusting in Tone Mapping, or suffer the long render times.

evilded777

Well, on a related note... is the Distant Light a native IRay light? I know Studio has a photometric option on it... but... its weird to  say the least. Any good options for using the  distant light as a sun/sky replacement?

Tobor

Iray supports what it calls an infinite light, which is the same as a distant light -- non-converging parallel rays. So I strongly suspect that when you choose a distant light, it actually connects to an  Iray infinite light.

You can use a distant light as sunlight, but there are fewer options for controlling shadows. The Sun-Sky settings let you do things like alter the haze, which has the effect of softening shadows.

With an Iray photometric distant light, the luminance value is lumens *at the scene*, rather than from the light source. Incident light is measured as if you are holding up a light meter in front of your subject. This means you need VERY low values to properly light the scene. Instead of the wacky 1500 lumens that the distant light defaults to, you only need about 9-11.

This correctly maps to the real world: in D|S, default scene units are in centimeters, so the incident light is lumens per square centimeter. At noon sun, there's about 9.3 lumens per square centimeter. Dialing the Luminosity to roughly 9 or 10 will approximate full noon day sun.