LC #42 Pipers Alley

View Full Version : sampling quality MR

03-22-2004, 05:41 PM
Hi everyone!

Would someone tell me how I can get a better result and fix this flickering problem?
Here's a crop of 20 frames in quicktime.
the test (

My render global setting is:
contrast RGBA at 0.07
minsample : 0
maxsample : 2
sample lock ON
jitter ON
filter Gauss 3 > Is this one contrast sensitive or not?

:love: Here's a very useful link.Mental Ray Sampling (adaptive sampling settings) (

As mentioned in the maya doc the prefiltering for fileTexture is not translated to MR.

The shading sample overwrite doesn't seem to make any difference.
The shader I used is a simple maya shader with just a dirtmap linked on the diffus.
I'll try tonight without dirtmap:hmm:

Thanx for your help

Wigaru Wiyamoto
03-23-2004, 11:49 AM
I was about to ask this. I'm getting horrible flicker from aliasing. In order to get acceptable results I'm doing min/max of 2 and using the triangle filter, but this results in considerable rendertime before taking anything like GI or FG into account.

The Lanczos filter produces some pretty nice and crisp images, though that makes aliasing that much more obvious.

Edit: Thanks for that link. I guess I should focus more on the contrast, no the samples. The diagnose sampling helps.

Edit2: I think I got the problem solved now. Since I'm only rendering a model turn-around I have the contrast values set VERY low (0.02). This way the backround/model is sampled once, but the edges are nicely oversampled. This is with 0/2 samples, btw. The diagnose samples feature is your friend.

03-23-2004, 01:38 PM
The diagnose samples feature is your friend.
Yes, that's true!

I thought that a max_sampling of 2 should be more than enough. ( I've never rendered with a maya sample 16 before MR).

Did you find a way to use mib_texture_filter_lookup? There is a broken link on

BTW with or without dirtmap the problem stays.

03-23-2004, 02:35 PM
The mib_texture_filter_lookup may solve this if it is texture AA problem.

I described how to set it up here

(repeated here for convenience)

MIB_texture_vector {outvalue} > {input} MIB_texture_remap
MIB_texture_remap {outvalue} > {coords} MIB_texture_filter_lookup
MIB_texture_remap {message} > {remap} MIB_texture_filter_lookup
MIB_texture_filter_lookup {outvalue} > material colour

Typical values are eccmax = 20
eccmin = 6
disc_r = 0.3
tex = file1 (where file1 is a custom MR file node created vis custom entites in render globals)

Set the repeat of you texture in MIB_texture_remap

It is a bit of a pain to create every time but you can write a Phenomena and implement the whole network as 1 node with a few important parameter interfaces (tex, repeat etc.).

03-23-2004, 04:46 PM
You can see my tutorial on how to set up a Phenomena in my sig if you do not know how.

03-23-2004, 05:43 PM
Thank you so much!
Let's see the test tomorow morning!

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