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Author Topic: colorID flickering\randomization at object edge  (Read 1278 times)

snguyen

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colorID flickering\randomization at object edge
« on: August 28, 2014, 09:05:01 PM »
the colorID function is awesome for varying geometry, but we have run into an issue with flickering between renders at the edges of surface objects.



the issue seems to be that forestPack is incorrectly interpreting colors from the ColorID texture at the edge of a uvw mapped object.  in the screenshot, the plane is mapped with a standard planar uvwMap modifier and the colorID texture that is used in the forestpack system, which is working pretty accurately across the surface of the plane but at the near left edge there are red boxes where no red appears in the color texture.   when this renders over a sequence of frames, this edge pops with different color correlated geometry spawning at each frame.

adjusting the uvwmapping size/scale even larger than the object doesn't resolve the issue, and it almost looks like some kind of rounding error at the very edge of the uv information.  this appears to be a bug, but is there anything we might be able to do to work around it?  is this a known issue?

attached is the max scene file that produced the screenshot.. any assistance is greatly appreciated.

thanks...





Michal Karmazín

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Re: colorID flickering\randomization at object edge
« Reply #1 on: August 29, 2014, 11:04:51 AM »
Hi,

Thanks for reporting this problem. We tested the provided scene, but we are unable to reproduce reported behaviour. Can you please send us some more information about your configuration?

Which version of 3ds Max (from your scene file I suppose it's 3ds Max 2014) and renderer (V-Ray, Mental Ray ...) are you using? Please provide us it´s release version also.

Does this problem appear while rendering locally or by using network rendering distributed rendering or backburner)?

Anyway, could you please do some quick test with texture Tiling disabled? Thanks in advance.

Kind regards,

snguyen

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Re: colorID flickering\randomization at object edge
« Reply #2 on: August 30, 2014, 01:33:47 AM »
Hi Michael,  does the viewport look differently than what i've displayed?  although the "flicker" only happens on render, it shouldn't need to go through the renderer to display the issue of spawning incorrect colorID objects...

regardless, we are on:
3dsmax 2014 SP3
Vray 3.05.07 build 24596
forestPack Pro 4.2.4

the flickering on render happens over a network render (deadline) only-- local rendering is fine.  it happens with or without tiling, and with or without modification of uv/bitmap parameters (at first we thought it might be a filtering issue).  if we use the plane's originally assigned uvs (from the primitive), it seems to work correctly, but applying custom uvs--even if they are simple planar ones--is where we see the inaccuracy.

Michal Karmazín

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Re: colorID flickering\randomization at object edge
« Reply #3 on: September 01, 2014, 05:50:30 PM »
Hi,

Thanks a lot for all additional details provided. With your help, we have reproduced this issue, which could occur on some render slaves when applied mapping modifier on surface used for scattering in UV mode. We'll have to investigate more in deep what's causing this problem. Meanwhile please use the XY mode which should be working without any issues.

Thanks for your comprehension and sorry for any inconvenience caused. We´ll keep you posted.

Kind regards,

snguyen

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Re: colorID flickering\randomization at object edge
« Reply #4 on: September 02, 2014, 07:33:46 PM »
Thanks, Michal.

i might be wrong, but i thought the "XY" mode wouldn't work for irregularly mapped objects (like a custom UV'd mesh)... is there another way to make it work for cases like that?

in the meantime, we have managed to work around the color issue by using separate forest systems for each object, but of course this isn't ideal.  any information you have about a fix for this would be greatly appreciated.

thanks!
greg

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Re: colorID flickering\randomization at object edge
« Reply #5 on: September 03, 2014, 06:25:27 PM »
Hi, we continue investigating this issue. It seems a multithreading bug.
As workaround, please try setting General->CPU Threads = 0. That should fix the problem.
Carlos Quintero
iToo Software

snguyen

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Re: colorID flickering\randomization at object edge
« Reply #6 on: September 10, 2014, 01:36:30 AM »
thanks, carlos!  we'll give it a shot...