Max Num Consec Reject

mrCarnivore · Post by **mrCarnivore** » Fri Mar 23, 2007 9:20 pm

Can anybody tell me what effect the value of the variable "Max Num Consec Reject" has on render speed and quality?

Deus · Post by **Deus** » Sat Mar 24, 2007 12:00 am

lower value = faster render time but less accurate.

i.e. It will appear to converge faster (less noisy) but it will be possible that some hard to reach light paths are not explored properly

mrCarnivore · Post by **mrCarnivore** » Sat Mar 24, 2007 12:06 am

So the result is not wrong but a too small value could lead to some areas staying darker as they would have been with a higher setting?

What is a sensible value? I guess it depends on the scene... But can you give any hints? Like when using glass you usually have to set it higher or something?

Deus · Post by **Deus** » Sat Mar 24, 2007 12:10 am

Default value is fine for most scenes. Lower it to make it go faster. But ofcourse it depends on the scene.

Let me try to explain (I hope i am right about this) consider a maze and camera in one end and light source in other end. room where camera is should in theory be hit by some light if max reject is too low the scene will be black. So you are about right carnivore.

mrCarnivore · Post by **mrCarnivore** » Sat Mar 24, 2007 12:17 am

Thx for the help.

But what is the default value? I think blendigo sets 500 and the exporter 1000, but I'm not sure...

Deus · Post by **Deus** » Sat Mar 24, 2007 12:21 am

Check the initfile that resides in the indigo main directory

CTZn · Post by **CTZn** » Sat Mar 24, 2007 2:25 am

I think there is a consensus on the effects of NCR, but what exactly is it plz ?

zsouthboy said: it's a waiting time; is it ? what for ? Or is it a number of tries for a light ray to reach the camera (or light source) ? If so, does the ray start over from the source when it doesn't finally reach the camera (after NCRn bounces) or does it resume from a later bounce ?

All renderer settings should be clearly exposed, at least I wish they will. As technical as they can be, they are usefull to know. People potentially able to understand them do care.

Thx

Post by **OnoSendai** » Sat Mar 24, 2007 2:27 am

It is the maximum number of consecutive rejections allowed in the Metropolis-Hastings algorithm before a mutation accept is forced.

CTZn · Post by **CTZn** » Sat Mar 24, 2007 2:35 am

That may do Ono, subsequent informations have to be found for "novices" but you gave enough hints to get the info.

Thank you very much, very appreciated !!!

Max Num Consec Reject

Max Num Consec Reject

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