PPT - Workflow?

[MegaPixel]

I've had Vray for maybe 4 months now and I'm just now getting around to playing with progressive path tracing. I glanced over the tutorial for it on the Vray starting page and sadly, I'm not getting the results I would expect to. When my rendering completes, it basically looks incomplete - like maybe the "don't render final image" box was checked only it wasn't.

No I don't have the image to upload for you because I'm posting out of office, but it was a simple empty interior with a grey overide on it rendered to 800x600. Light Cache was set as both primary and secondary GI, I had about 4000 lightcache subdivs and everything else was default.

So for someone who doesn't give a darn about render times, what does one have to do to get a noise free, unbiased clean image at 800x600 using PPT?

Thanks - Daver

[vlado]

You can email me an image to vlado@chaosgroup.com if that is possible; I suppose that you may have missed a check-box somewhere...

Best regards,
Vlado

[Paul Oblomov]

Well, make sure your Lightcache is set to Progressive Path Tracing mode, and I think that you shouldn't bother on "biased or unbiased".... who cares ? Try playing with sample size (increase it a little - in this case it can't be called "100% unbiased", lemme say "90% unbiased" ). This will decrease rendertime.

P.S. Rendered in 30 minutes. And look Here - maybe you're getting the same picture, as isma at the beginning.
http://img293.imageshack.us/img293/2415/30mincp6.jpg

[CCS]

As long as there is a human at the keyboard, the render is going to biased.

[DaForce]

Sounds like you didnt choose PPT. As just changing to LC/LC isnt enough to activate PPT.

Also perhaps 4000 subs isnt enough.. just crank it up to like 50000 and then stop it when the image is at the level you want.

[alexthg]

Just curious, can you 'continue' a PPT rendering? I mean if I cancelled a render at midpoint, or if i put not enough subdivision and want to add more?

[DaForce]

not as far as I know. Well not properly anyway.

[MegaPixel]

DaForce Posted: Thu Aug 31, 2006 3:59 pm Post subject:

--------------------------------------------------------------------------------

Sounds like you didnt choose PPT. As just changing to LC/LC isnt enough to activate PPT.

[/quote]

I actually did have the Progressive Path Tracing Option checked Bro. I think the problem was that I only had about 4000 subdivs so when it stopped, it was pretty damn noisy. I didn't realize that some folks could just throw it way up to 50K and terminate when they were satisfied.

Is there a recommended Sampling method to use while using PPT (fixed, qmc, adaptive) and would adjusting the QMC adaptive amount or global subdivs do anything?

Dave

[Paul Oblomov]

It doesn't look at AA method, as it doesn't use it

[MegaPixel]

AA meaning anti aliasing? So my wether I have catmul or area selected, it doesn't matter with PPT? Ok are there any other parameters that matter?

[Paul Oblomov]

AA filter is taken into account. But slows down...

[MegaPixel]

Wait, first you said:

Paul Oblomov Posted: Fri Sep 01, 2006 3:52 am Post subject:

--------------------------------------------------------------------------------

It doesn't look at AA method, as it doesn't use it

Then you said:

Paul Oblomov Posted: Fri Sep 01, 2006 4:03 am Post subject:

--------------------------------------------------------------------------------

AA filter is taken into account. But slows down...

What gives man?

[Pixelab]

AA method is not AA filter

When your work with PPT, uncheck AA filter

[MegaPixel]

Thank you for clearing that point up because I was getting confused in a hurry. So no AA "Method" is considered during PPT however AA "Filters" are. What other parameters are considered that could have a big impact on the final result, if any?

Thanks again - Dave

[Paul Oblomov]

To speed things up (and to reduce noise) - play with sample size (increase it) and uncheck AA filter. That's it. Then you may look at the "adaptive amount" in rQMC sampler rollout. The lower - the longer, but less noise.