problem with splotch

[azman_821009]

hi guys,

i am working on the animation of office interior. I did some test render and found the splotch at wall, ceiling and cabinet. How can I solve this problem.

Thank you..

[Janusz Biela]

Skyportals

Please upload scene (no furniture, only walls) if You can.
If not then increase N parameter up to 3000.
Also check GI resolution: ~ 300 mm
Put bigger min/max rays for FG: 400/2000
Put 2 passes.
If You have still problems then put shader Limit DR for ceiling lamps.

This is "deep corner" so photons has always problem to by attach correctly on the surfaces. This is normal and only Skyportals can help (but not now - is too difficult)
Those splotches appear, because balance between photons from lamps and photons from another sources of light are not correct. Also this is normal. You can use correction tool: Luminosity Number Multiplier (try ~5000).

[azman_821009]

Hi Janusz,

Here is the scene.

Temp_Test.rar

(127.14 KiB) Downloaded 353 times

Anyway, if i want to do the bake GI for interior, what is the better step of rendering for frame?

Thanks.

[Janusz Biela]

This setup of Kray which is inside scene You use it?
Step depends from speed camera track. I think You can setup 20-30 frames step. The faster camera moving, then step must be smaller.
In attachment my setup (I know is quite heavy but is not good solution for luminosity from lamps especially when rooms are dark...) Instead of Lumi You can use Area Lights...but amount of direct ray tracing calculations will grow up geometrically with amount of light...In K3.0 we will solve this problem.
Remember desaturate shader for strong red colours.

[khan973]

Janusz, whay for a while your best advice was to use lumi polygons and now you suggest Area? What made you change your mind?

[Janusz Biela]

Janusz, whay for a while your best advice was to use lumi polygons and now you suggest Area? What made you change your mind?

If source of light is one or two windows then better to use Area Lights. But of course that situation is very rare...so I suggest to use lumi panels. Increasing amount of Area light You increase amount ray-tracing calculations. This can be bad for speed render. We do not heave still shade for area lights - then better is to stick with lumi poly (which as interpolated light has almost no limits)

[khan973]

I've tried both and in many cases, I found that the shadows were way better with Area lights.
They also bring more "contrast". The look with lumi panels seems more "soft". Maybe it's a matter of power shader? size?

[Janusz Biela]

I've tried both and in many cases, I found that the shadows were way better with Area lights.
They also bring more "contrast". The look with lumi panels seems more "soft". Maybe it's a matter of power shader? size?

If You will turn Kray to QMC or Path tracing then difference between Area Lights and Lumi panels will be very small. Lumi panels method has "soft" light feeling because shadows are interpolated - is not ray traced as Area Light when each pixel is calculated.
Positive thinks for interpolated GI:
- render completely without noise (with another engines situation can be different, noise threshold sometimes is added to speed up render)
- easy setup (source of light you build in Modeler)
- better blur
- faster AA
- no limits with source of light (Kray start render slow with 5 or more Area Lights....but in my Auditorium scene I used over 200 spot lights and area lights and still speed was comfortable)

[khan973]

Thanks for the emplanation