Gi/Animation Problem - splotches

[Olli96]

Hello, i could use some help again. This time its about animations and splotches. I cant identify what is causing the problem so i need you guys

Here you can find two examples:
http://prntscr.com/79wy8k
http://prntscr.com/79wwpf

and this are my GI Settings:
http://prntscr.com/79wwgd
http://prntscr.com/79wwwv

i basically have those splotches in all my shots, always in the corner of the room or where the wall hits the ceiling, everything else is fine, even small details like the skirting board is fine and without splotchs.

Light Cache was calculated in fly-though mode and the irradiance map by using multiframe incremantal mode, every 5th frame. Both animatons are just a 200 frames slow pan with the camera, so nothing fancy or fast movements. I was usually getting away with those settings in previeous projects, in fact i have used much less subdivs for the irradiance map before. The scene is lit by Target Light and some Vray Lights set to sky portals with 42 subdivs.

Increasing the interpolation samples of the irradiance map helps a bit but its still not clean and increases the rendertime quite a lot. If i render a single frame and dont use a saved gi solution it renders without problems.

Here is a single frame and the settings i used for it:
http://prntscr.com/79x2l5
http://prntscr.com/79x32g
Settings: http://prntscr.com/79x37h

Where is my mistake or does anyone have some pointers whats going on? Why does it render fine using single frame modes but falls apart if i use multiframe incremental? Any help is much appreciated

[Olli96]

Could the Light Cache be the problem? I did some testing with brute force as the secondary engine and so far it looks good and clean. I will let run a test overnight and report back tomorrow. If anyone has some ideas, please post

[Olli96]

Well, something was wrong with my light cache, it rendered flawless with brute force as the secondary gi engine. Any ides for the future what was causing this? 6k subdivs and a sample size of 0.5cm should be more then enough for a 200 frame animation, at least in previous animations i did get away with half of the subdivs...
http://prntscr.com/79wwwv

[svetlozar.draganov]

These high settings should not produce such splotches.
Would it be possible to restore the default LC settings and run another test render?
If the result is the same we will need the scene in order to investigate what's going on.

[Olli96]

Its possible, just give me some time to render the animation with brute force now and i will run a new test once its done.
What do you mean by restoring the default settings? Do you want me to calculate the lc in flythrough mode using the default settings?

[vlado]

Would it be possible to post a render with the light cache as both primary and secondary engine? The problem is definitely in the light cache, but it's hard to see what is going without looking at the light cache itself.

Best regards,
Vlado

[svetlozar.draganov]

Fell free to contact us once the animation is completed.
What I meant is to use the default Light Cache settings in flythrough mode.

[super gnu]

ive always found that using world-scale samples for lightcache is unneccesary, and increases blotchyness, calc time and lc file size, as does a small sample size, with no noticeable improvement in final gi quality.

default settings (often with incresed subdiv mult. and retrace on) works well for all scenes, including long flythroughs. a soft but clean lightcache is far preferable to a detailed noisy one, since its only ever used as a precursor to the primary gi.