randomizing MASH color node - rendering artifacts

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Davide Bestetti asked · Mar 28, 2020 at 08:58 PM

randomizing MASH color node - rendering artifacts

Hi
I'm experimenting a few problems when trying to randomize colors of a MASH network in Maya, Arnold Render.
Trying to set up things with the Repromesh, although with the instancer utilizing an AiUtility instead of a AiUserDataColor everything works fine.

This is the Network i built so far:

Repromash with Aiopaque off (shader has Transmission @1), Export colorvertex on.
MASH color node with random value set to 1

This is what i see in my render view, certain pills render out incorrect, seems like a chromatic aberration on vertex..!!

Seems like this issue is connected to the MASHcolor.randomvalue, if i 0 it out, i get no more scatter of colours of course but i don't get anymore this problem.

Any advice?

arnold render mtoa

random-color-network.png (57.7 KiB)

color-problem.png (289.9 KiB)

random-color-network.png (57.7 KiB)

color-problem.png (289.9 KiB)

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Answer 1 · 2020-03-30T15:53:16Z

Davide Bestetti answered · Mar 30, 2020 at 03:53 PM

Hi Lee
Utility is set to Object, it works in combo with the Instancer. I'm experimenting problems with the colors, but meh..

Repromesh with AiUserDataColor create the problem shown above. Noone of the modifications of the shader help fix it.

_____

I'm experimenting another problem (really?):

I added a Dynamic node, animated the number of point to have a linear spawn of pills along time.
The goal is to fill a glass with pills.
Problem is that after first pills simulation slows down (due to the amount of instanced obj i think) but the spawn does not.
The following video shows the problem:

https://youtu.be/o5DY9hyieoU

It is noticeable that the simulation runs in a totally different ways (more and more pills on the screen, but the spawn is linear).
Am i doing something wrong?
This is quite a simple simulation. Should i give up with MASH and jump to Houdini?

David

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Lee Griggs · Mar 31, 2020 at 07:17 AM

Have you tried baking the simulation?

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Davide Bestetti Lee Griggs · Mar 31, 2020 at 08:59 AM

I was not trying because i was wrongly sure that a stand in which is procedural would not have worked with the Utility node network.
I tested out and it works..it's not time to try the baking process!
Thanks Lee, i will update once done.

1 · ·

Davide Bestetti Lee Griggs · Apr 03, 2020 at 10:29 AM

Hi Lee

https://youtu.be/84hlh05AcQw

Caching the sim solved the main problem of "slowing down" new spawns, but:

I think the utility node is having problems with unique ID's for each new-spawn objects. (in this sim numberOfPoints of the distribute has been animated)
Tested out with a vertical column of 400 pills, problem is solved.

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Answer 2 · 2020-03-30T06:59:03Z

Lee Griggs answered · Mar 30, 2020 at 06:59 AM

Which color_mode is the utility set to?

Does changing any of the standard_surface attributes affect it? eg transmission_depth?

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