Detail enhancement - animations

[panthon]

Hi there,

we are exploring new possibilities in vray 1.5 and one of them is using detail enhancement in animations where the only thing is moving is the cam. As i see it right now, it looks like this feature uses qmc calculations to make fine shadows detail show up, therefore you cannot save this infomation with the irradiance map, although the place where it's located - under irradiance maps settings - could make u think it's a part of IM. Is it impossible to store all this extra shadow info inside an irradiance map? Should we consider it as a kind of "adaptive" QMC?
I was thinking of "store with irradiance map" option under Vraylight parameters.
I like the flicker-less look u get with precalculated maps but using this new feature can introduce some noise if the settings are not high enough, so, do u think detail enhancement could/should be used for walkthrough renderings?

Thanks!

[vlado]

When you use the detail enhancement, the GI information is split in two parts. One part is for the large flat surfaces and it is stored with the irradiance map. The other part is for the small details and it is calculated during the actual rendering.

You can save and re-use the irradiance map portion of the solution as you would do with a regular irradiance map. The only thing to keep in mind when rendering fly-through animations is to use the World scale for the detail enhancement.

Best regards,
Vlado

[studioDIM]

Is there a particular reason why i would use this method, instead of a rough LC + QMC?
I find it harder to specify the sampling for the detail enhancement pass as fractions of HSubdivs than in samples as i'd do for the pure QMC GI, but that may just be my frame of mind, and haven't quite understood what are the differences (aside from the radius, like for an OCPass) between this and QMC GI.
If i keep the radius small to have it work quickly, in archviz i often see the darker line fairly strong in the corners of walls, and if i increase the radius to give me a softer solution, rendertimes grow in the park of QMC GI...

Maybe the trick is that it works well for animation, thanks to the world sample scale and the coupling with IRMap?
Sorry to be so openly dumbfounded, but it had me scratching for a bit now...

Lele

EDIT: trying to substantiate the claims, here are two small crops. One rendered with LC+IRMap+DE in 1:21 (Default 128 gray material, sun+sky,physcam, default parameters for everything, but for reflective caustics turned on in the GI panel) , the other with LC+QMC, same setup as before, 16 QMC GI Subdivs, 1:03.
Which is which?

[vlado]

What settings did you use for the irradiance map?

Best regards,
Vlado

[studioDIM]

default ones at high.

Lele

[vlado]

default ones at high

There isn't much point in that as then the DE time is added to that of the irradiance map so it's natural that the result is slower. However, if you use lower irradiance map settings (e.g. Medium preset), the render time will probably end up similar.

Best regards,
Vlado

[studioDIM]

Fair enough, i stand corrected.
Still, can you confirm it is a matter of preference/situation, rather than a general method?
I could think of situations where sharpness of detail is uneven across the frame, where this would come in very handy, but others where fine detail is spread across, at which point a straight qmc would work a bit better...
Or am i off?

One thing i noticed about the rc2, though, is that at some point i haven't been yet able to lay my finger on, the renderer slows down mightily.
What would take a minute to render upon file open, renders in twice the time at least.
Only closing max and reloading the scene fixes it.
Anyone experiencing it?

Lele

[vlado]

Still, can you confirm it is a matter of preference/situation, rather than a general method?

Yep, pretty much.

I could think of situations where sharpness of detail is uneven across the frame, where this would come in very handy, but others where fine detail is spread across, at which point a straight qmc would work a bit better...
Or am i off?

This is correct, yes.

One thing i noticed about the rc2, though, is that at some point i haven't been yet able to lay my finger on, the renderer slows down mightily.
What would take a minute to render upon file open, renders in twice the time at least.
Only closing max and reloading the scene fixes it.
Anyone experiencing it?

It has not been reported so far, but it might be worth to take a look at your memory usage when this happens again. Is your scene memory-heavy? What are you doing in between the renders (e.g. modelling, adjust materials etc)? This might have something to do with memory fragmentation.

Best regards,
Vlado

[studioDIM]

I just change settings for the renderer, and F9 a crop into max's VFB.
Over and over.
Cancel mid-way, most times, and sometimes bring to completion.
It did happen to me with very simple test scenes, and always only with RC2, but erratically.
I'll try and pinpoint something that might spark the behaviour (might just be my max 8 doing silly things, i admit...).

Anyways, thanks for the answers!

Lele

[tricky]

...to clarify:

1) DE is calculated at rendertime, so may be slower than higher IRmap settings for many frames of an animation
2) Radius should generally be left at default settings, except at world scale, for interior animations, regardless of the scale of the scene - eg, my room measures 4x5x2.5 (meters), so a setting of 60 at world scale is fine

[Candelero]

Think of the DE as an occluded pass ( VRayDirt )
If you render your scene with an override material, which includes the VRayDirt map. So the zones where the dirt is visible ( radius dependant ) would be zones where the DE would be considered.

Best regards,
nikki Candelero

[RErender]

It willl also depend on your scene, a typical room that is mostly empty wall will benefit from DE since the IMap can be set quite low.

[vlado]

1) DE is calculated at rendertime, so may be slower than higher IRmap settings for many frames of an animation.

This is correct, yes.

2) Radius should generally be left at default settings, except at world scale, for interior animations, regardless of the scale of the scene - eg, my room measures 4x5x2.5 (meters), so a setting of 60 at world scale is fine

For animations, you *must* use world scale; in that case, the setting is scene-dependent and does depend on the scale. Like Candelero said, you can get a quick preview of where you'll get the detail enhancement by using VRayDirt.

Best regards,
Vlado