Irradiance Particles Questions

[hsa]

I have just started playing with this stuff in Max Design 2009 and my questions are specific to exterior lighting.

 

1) Is there a need for enabling importons with an exterior render?

 

2) I can get a nice output with high settings but jesus the render times are enormous. I have read something about starting with low settings and then freezing the ip map before raising the quality and re-rendering but I am unsure when I am supposed to actually cancel the render. There are several passes it seems and I don't know if I am supposed to wait until it actually starts rendering the image or before (confused)

 

has anybody dialed in an acceptable workflow with this technique? I am very interested but a bit in the dark on how to correctly speed up the process.

 

Thanks for any help!