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Old 06-10-2004, 01:56 PM   #1
brosseau
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Default Texture Flickers

Hi,
I am working on an internship project where I am creating a 3D map of my college's campus and the surrounding area. I have a polygon terrain which I textured with an orthographic image of the area. When I rendered a simple camera fly-through, though, there was a lot of tiny flickering all over the terrain texture - especially where there were white or light colored objects on the texture. I assigned it as a lambert, so it shouldn't be reflective. I'm noticing the same effect on some of my other textures - brick walls, gravel etc, but not as noticable.

Is this a lighting or texturing problem? I don't know much about the settings in either lighting or texturing. Can anyone give me some suggestions as to where to begin?

Thanks!
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Old 06-10-2004, 02:25 PM   #2
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Two things that I would check is that you don't have over-lapping geometry and the other is the direction of your normals.

If you need more explination then just ask
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Old 06-10-2004, 02:27 PM   #3
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Also what type of shadows are you using D-map or ray traced and what renderer are you using Maya Software renderer or Mental Ray? but sounds like a geometry problem as mentioned above
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Old 06-10-2004, 02:37 PM   #4
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Thanks so much for the quick replies! I am rendering in MentalRay, but I'll have to get back to you tomorrow about the settings used - I have picked up this project from another intern and he set all the render settings, so I'll have to look them up.

Normals.......ah, I have read about them but really don't understand them. How do I check what direction they are in? I am positive that there is no overlapping geometry - some of the objects that the textures flicker on - including the terrain are based on simple poly plains, so I'm interested to learn more about the normals.

Thanks!
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Old 06-10-2004, 02:40 PM   #5
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So if you are using mental ray this may be the problem. Are you using global illumination because you might not have final gather rays high enough. Usually this will cause a problem during animation. The reason is that when you render with final gather on by default it will create a new map for everyframe so this may affect the render and get the artifacting on the surfaces. Check it out and let me know.
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Old 06-10-2004, 04:40 PM   #6
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As for checking the normals (just for reference).

Select the object, goto
Display ----> Polygon Components ----> Normals

This will show the direction that your geometry is faceing, but I have a feeling it is your render options. But it's good to know about these never the less.
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Old 06-10-2004, 08:43 PM   #7
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If there is a normal problem I would suggest using the Edit polygons>normals>conform. This is helpful if most of the polygons are correct, but some are not. It will make the ones that are not,conform to same direction as the majority. If it doesn't solve the problem you learned something new anyway.
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Old 07-10-2004, 06:56 AM   #8
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I know I have
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Old 07-10-2004, 12:54 PM   #9
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Ok, I checked the normals and they are ll facing in the correct direction. Just in case, I used the conform command anyway - thanks for that suggestion.

Here are the settings in Mental Ray:

Ray Tracing is "on" with all settings at "1", scanline "openGL" and faces "both".

Shadows has Shadow Method "segments" and Shadow Maps "on".

Motion Blur, Caustics and Global Illumination and Final Gather are all unchecked.

Sampling Quality has all Contrast settings set to "0.1", Min Samples "-2", Max Samples "0", Sample Lock is checked and Jitter is unchecked.

I have never adjusted any settings in Mental Ray before, so any suggestions would be greatly appreciated!

Thanks again.
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Old 07-10-2004, 12:56 PM   #10
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Is it possible to get a screen grab and post it?
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Old 07-10-2004, 05:49 PM   #11
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I think I'm going to have to try re-rendering the file before troubleshooting this problem any more. I have been bouncing back and forth between two different computers for this project because this one doesn't have the RAM to handle rendering this file in Mental Ray any more - so I render on a different computer and I'm now wondering if settings on the other computer affected the render. I have some older still shots that were rendered on this computer that are much better quality overall.....thanks for everyone's input, hopefully when I take a closer look at the settings when I render again I will find the problem I had.

I appreciate your suggestions!
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