Flickering Reflections

[Dmerc]

We are working on a movie presentation right now, and as you can see in the sample-movie, we have a problem with flickering reflections. At some points the edges of these lights are pretty jagged as well.


www.xoio.de/public/flackern.mov


Subpixel mapping is ticked on.

The reflected pseudo-lights are in fact cylinders in the ceiling with a vray-light material and a strong multiplier of 10+ to make them highlight strongly on the carpaint gi-output turned off). This is, because we have to show tons of these downlights, so the reflections are impossible to do with regular lights.

I would guess it is a antialiasing problem, but I am not very good at this: We are using adaptive subdivision with a 1.5 area filter.

How could you get around this and have the edges antialias properly ?

BTW, since we are doing this for animation-purposes we can't afford exploding rendertimes

Thanx for your help in advance, Peter

[percydaman]

saying you use adaptive subdivision without mentioning the sample settings isn't super helpful. Also, which can you least afford, poor/flickering reflections, or longer rendertimes?

[Dmerc]

Antialiasing settings:

Hmm, alright. True. As I said I never dared to play with these too much:

a) settings are:

Min -1
Max 2
Color threshhold 0,1
No outline
no normal threshhold
yes randomize samples
obviously not show samples

b) Considering Rendertime:

Well, you know, it's never an A or B solution. It would definitely hurt, if rendertimes would double, but we could spare another couple of seconds.

Is adaptive sampling the right solution for animation purposes anyhow or would I choose another ?

Thanx in advance and have a nice weekend !

Cheers, P

[percydaman]

-1,2 is sufficient for animation I'm afraid. 0,2 or even 0,3 would help your problem. Sometimes adaptive DMC AA can do a better job. i'd recommend taking a look at the manual. It would explain it better then I could.

[Morbid Angel]

undersampling is not a good idea for final renders....ever.
My recomendation for you, when rendering with hot specular/reflection highlites to use a higher aliasing, something like 1/2, or 1/3 for adaptive subdivision.
For adaptive dmc, 1/16 or 1/24 with noise threshold of 0.004 should do the job.

[Dmerc]

Regards

I thank you kindly, and will try the adapted settings asap !

Best regards, Peter