When is QMC Sampler Applied?

V-Ray for 3ds Max V-Ray for 3ds Max :: General
1

I don’t fully understand all the mechanics of Vray so hence my question. When is the QMC Sampler applied during the calculating process (what rendering time in particular is effected)?

2

Have you looked at this

Best regards,
nikki Candelero

3

I guess I should phrase it differently - Does QMC sampler affect (or is applied during the following phases):

1) IR Map Calculation
2) LC Calculation
3) Final Rendering

4

1 - yes
2 - not sure but I don’t think so
3 - yes for AA and anything else with subdivisions

5

3 - yes for AA and anything else with subdivisions

I DEFINITELY don’t know the answer for sure, but I don’t think QMC is taken into account for AA unless you are using QMC type AA. If you are using Adaptive or Fixed, it wouldn’t apply (I don’t think).

6 
QMC (Quasi Monte Carlo) sampling is employed throughout VRay for every "blurry" value - antialiasing, depth of field, indirect illumination, area lights, gossy reflection/refraction, translucency, motion blur etc. QMC sampling is used to determine what samples should be taken and, ultimately, which rays to trace.

Instead of having separate methods for sampling each of those blurry values, VRay has a single unified framework that determines how many and what exactly samples to be taken for a particular value, depending on the context in which that value is required. This framework is called the QMC sampler.

re,
Lele

7

QMC sampler has effect on everything, except:
-LC
-photon mapped caustics
-photon map

It does affect AA, regardless of the type you choose. It’s effect is most noticable in QMC AA and fixed.

There is a post on the forum where Vlado states all this, altough he says it doesn’t affect AA which seems wrong to me, just test it.

http://www.chaosgroup.com/forum/phpBB2/viewtopic.php?p=73539&highlight=qmc+dof#73539

8

It won’t affect LC, but it will affect PPT, only with two parameters out of five: adaptive amount and time independent.
Which makes sense having since ppt desl with all of the scene, not only GI.

Lele

9

So if I use IR/LC, QMC Sampler is only applied at the IRMap calculation phase and doesn’t really impact final rendering?

10

right, unless your using AA, glossy mats, shadows, etc…