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View Full Version : Light Flicker - What the BEEP!



digitalimagery
10-10-2013, 08:16 AM
Thought I had a usable final file until I looked at this test and saw flickering. Can anyone enlighten me as to what causes this? I've never experienced it before.

I have three lights in this scene, two area lights (one behind the floor panel which is off), and the default distant light. So really only two that are being used. Before I toss the one that is off as the culprit, I'd like to learn if it's the problem child and if so why.

I've attached my set up and the .mp4 can be seen here https://vimeo.com/76613037

Thanks to anyone who chimes in.

DId

dulo
10-10-2013, 08:24 AM
For me it looks like GI flickering. Are you shure you dont have GI activated ??

digitalimagery
10-10-2013, 08:27 AM
I'd tell you if I knew what "GI" is (still learning this application) can you expand?

Thanks for the reply.
DI

Danner
10-10-2013, 08:48 AM
Global Illumination, as in Radiosity.

If you can't get the look you want with lights + ambient occlusion alone and need GI, then you have to use animated radiosity cache or non interpolated GI because you are moving stuff other than the camera.

digitalimagery
10-10-2013, 08:56 AM
Got it. This is my set up in the GI tab. It's pretty much the way I render most of my files but not really fully understanding what each item really does (self taught - and honestly I think the manual is pretty vague in a lot of areas.

Does this tell you what's causing it? Should I check/un check something? By the way, I see "Blur Background" is checked. I'm using DOF and notice what a render hit that causes. Does "Blur Background" need to be checked? Is it slowing the render even further?

Thanks.

DI

117574

RebelHill
10-10-2013, 08:59 AM
see here..

http://www.youtube.com/watch?v=0YFZ2av-BLg&list=PL8A1C0DB658775A63&index=2

digitalimagery
10-10-2013, 09:00 AM
Well how cool is that? Thanks RebelHill. Watching now.

DI

digitalimagery
10-10-2013, 09:05 AM
Well right off the bat I've noticed none of my preferences/CS panel lights were set to sRGB. I remember having had a lighting issue in the past and I checged these to sRGB and now I see they're again not set. What causes these to change once they're set?

Not a show stopper just curious (for the future). Thanks again everyone.

DI

digitalimagery
10-10-2013, 11:02 AM
Bought the material - AMAZING content (that I can afford). Thanks so much!

DI


see here..

http://www.youtube.com/watch?v=0YFZ2av-BLg&list=PL8A1C0DB658775A63&index=2

RebelHill
10-10-2013, 11:34 AM
Bought the material - AMAZING content (that I can afford). Thanks so much!

Cheers, I hope you get a lot of good out of it and render outcomes that satisfy.

digitalimagery
10-10-2013, 11:36 AM
I'm sure I will. It's extremely thorough and exactly what I needed.

Thanks a million.
DI


Cheers, I hope you get a lot of good out of it and render outcomes that satisfy.

digitalimagery
10-10-2013, 12:07 PM
RebelHill,

Is this the proper forum to ask a question regarding the tutorial from cmi or should I contact you via that site?

DI

RebelHill
10-10-2013, 12:18 PM
Noes... u can ask away here I do suppose

digitalimagery
10-10-2013, 12:32 PM
First off Iím using LW ver 10.10.13

You saw the flicker problem on the logo which sits on a flat plane with a camera pan across it (That was 3 secs of a 4 sec anim. Ė 1 of four parts) which will be dissolved together for the final composited animation.

Questions:

1. Iíve saved each camera move as a separate file.

Iíve done the test as in the tut and see the problem but for the final render do I just set everything up as I want for the final render, Bake 1 frame and then leave the cache option checked and render my final scene?

If this is correct do I use the Bake Radiosity Scene button for the final render or use the normal render scene (F10) and LW knows based on ďCacheĒ being checked in the GI tab?

2. If Iím using DOF do I bake my radiosity cache file with that enabled? I assume yes.

3. Finally If I want to gang render the four files over the weekend, do I need to open each file, do a Bake Radiosity Frame and lock the preprocess and then save the file so LW will retain the Baked frame for each individual file saved?

Do I need to create different directories for the baked cache frame of each file to be rendered?

In all honesty I havenít finished the entire tut where my situation was addressed near the beginning (camera move only). If these answers are covered in the later parts of the tutorial Iíll finish it for the answers. Time is tight and Iím trying to get these renders going.

Thank you
DI

RebelHill
10-10-2013, 01:34 PM
As you see in the latter portion of the first vid... with cache checked (and at least 1 frame baked/rendered), your sample placements become locked. If you camera however then moves to a new view with areas seen that were not directly visible in the first frame then you get big fat splotches, and maybe the occasional "pop" flicker. So what you really want is to cache up samples for the whole camera move, so set things up... do the bake radiosity scene, and once done, lock cache and render as normal (ideally, not changing anything in between, the first vid detailed some of what you can or cant change after baking, DOF is something u can as its not affecting the light/shade of the geo, its altering the cameras perception of that geo).

If your 4 files are different to one another... then yes, each gets its own bake. If however theyr'e the same scene, jsut rendered with different cameras/moves... then no. Where you have a single camera, going from one position on one frame to another position on another, it is no different if you had 2 cameras, one in each position, but on the same frame... the camera is (kind of) irrelevant... radisoity is a SCENE effect/attribute, not a camera one.

lertola2
10-10-2013, 01:44 PM
You can turn off "Interpolated" in the global illumination panel. This will increase your render times but you avoid the tedium of figuring out what interpolation settings will give you acceptable renders.

digitalimagery
10-10-2013, 03:49 PM
As you see in the latter portion of the first vid... with cache checked (and at least 1 frame baked/rendered), your sample placements become locked. If you camera however then moves to a new view with areas seen that were not directly visible in the first frame then you get big fat splotches, and maybe the occasional "pop" flicker. So what you really want is to cache up samples for the whole camera move, so set things up... do the bake radiosity scene, and once done, lock cache and render as normal (ideally, not changing anything in between, the first vid detailed some of what you can or cant change after baking, DOF is something u can as its not affecting the light/shade of the geo, its altering the cameras perception of that geo).

If your 4 files are different to one another... then yes, each gets its own bake. If however theyr'e the same scene, jsut rendered with different cameras/moves... then no. Where you have a single camera, going from one position on one frame to another position on another, it is no different if you had 2 cameras, one in each position, but on the same frame... the camera is (kind of) irrelevant... radisoity is a SCENE effect/attribute, not a camera one.

Rebel Hill,

I wrote a thank you note with a couple of additional questions that I had but the page hung and I've apparently lost them. Anyway I learned so much today and love your lessons. Thank you so much for your knowledge and expertise in LW. We're lucky to have you.

Blessings,
DI

- - - Updated - - -

Thanks lertola, we established that. I'm trying to understand the value of baking for faster render times. I get a lot of logo work and some of it has fast turnaround times.

DI