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Flickering issue, vray animation.
show user profile  albongino
Greetings guys, long time no see,

I have a quick question related to flickering during a short exterior sequence,

I have used Irmap and light cache.
I have made prepasses for both.
For LC, I made the prepass with LC on both primary and secondary bounces. 4000 rays, 0.02 screen, 15, nearest. No LC for glossy rays.

Then I loaded it as a secondary bounce (from file) to calculate the Irmap.
Irmap on mid settings, multiframe incremental, every 10th frame, once baked, I assume it's not supposed to flicker.
Rendered with adaptive dmc on default settings.
Area AA at 1.7

When I rendered the sequence i noticed medium to mid-high flickering on vegetation spots or where a lot of detail is.

Could the light cache settings be the cause for this?

If I decided to use Brute Force for secondary bounces, could I re-use the Irmap I already have? or does it have light cache data already into it ( since it was made using LC from file as secondary) and the issues will remain?

Any help would be really appreciated,

read 1733 times
12/20/2011 5:46:20 AM (last edit: 12/20/2011 5:46:20 AM)
show user profile  zeefusion
If the geometry you are trying to render is smaller than a pixel it can cause flickering. Rendering 2x your final resolution will help and then down size it in post.

You can also look at setting your irradiance map settings higher such as your Hsph subdivs to say 100 – 120. Increase your interp samples which will blur the samples to hide the flickering, but not to much or you will loose the GI detail.

read 1709 times
12/20/2011 10:04:16 AM (last edit: 12/20/2011 10:04:34 AM)
show user profile  Garp
Just a shot in the wild but have you checked your ir map with the ir map viewer?
With tiny details like vegetation, chances are that lots of spots have been missed with multiframe incremental set to 1/10.

Also don't throw that ir map away. I don't remeber exactly how it's done but you can add ir maps together. That's all the more information for the rendering part (unless you change something in the scene). So if you do make another one, maybe keep it at every 10th frame but start at frame 5 to get frames inbetween and cover more ground. Then combine it with the first one.

As I remember it, the ir map just has ir map data in it. It doesn't know which secondary bounce was used to compute them. You shouldn't have any problem adding ir maps made with different secondary bounce methods.

read 1702 times
12/20/2011 10:36:20 AM (last edit: 12/20/2011 10:37:55 AM)
show user profile  albongino
Thanks guys,

Zeefusion, for sure in this situation some samples will be smaller than a pixel (distant trees), and I won't be able to render double size, I was actually planning to do half size cache!!! I will give a try to a re-render with brute force a few frames to see if it persists.

Garp, Yes indeed, I could merge irmaps together using Irmap Viewer, the thing is that irmaps when baked are not supposed to cause flickering, but poor irmaps display splotches which can be corrected that way.. For the animation I did every 10th was clean enough..

I will render about 10 frames using brute force to see if it works, if not, I will increase Irmap settings, and dmc settings and see if it works..

read 1680 times
12/21/2011 2:33:21 AM (last edit: 12/21/2011 2:33:21 AM)
show user profile  killerbee2
To check what's flickering render a quick test of a couple of frames with only the primary bounces, my guess is that's your problem. Simulate Imap per frame with the High Animation preset + increasing Hsph. subdivisions to 100, interp. samples 50. If it still persists in Settings increase global subdivs multiplier.

read 1666 times
12/21/2011 12:04:08 PM (last edit: 12/21/2011 12:04:08 PM)
show user profile  albongino
Thanks KB,

I did try 15 frames with Brute Force and the damn flickering persists.

I will do the primary only test although i'm almost sure now it's the Irmap.

[EDIT] Just did a pass without GI at all, and flickering issue persists. could it be adaptive DMC?

I have it to min1 - max4 , Noise Threshold 0.01


read 1661 times
12/21/2011 5:38:33 PM (last edit: 12/21/2011 6:15:00 PM)
show user profile  GirishDJoshi
Have increased the sub divs of your maps, lights. They are quite essential as well.

then ask Bolt's.

3D ArchVis


Girish Joshi Photography

read 1651 times
12/21/2011 7:58:22 PM (last edit: 12/21/2011 7:58:22 PM)
show user profile  albongino
Hey Inxa, Happy Holidays!

I think it came down to shaders, I increased the DMC a bit and noise threshold down and it improved. but now it's taking TIME that I don't have.

I wil polish the shaders a bit to get faster render times and hopefully call it a day.


read 1643 times
12/21/2011 11:20:03 PM (last edit: 12/21/2011 11:20:03 PM)
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