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Vray Mesh Noise


madlios
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I discovered something with Vray that i cant find a way to fix. I have used Vray for 1 day now. It is a great tool, i had few problems at first, but it was really easy to fix after a few hours searching on net. So everything is fine. Except for 1 problem.

I use 3dsmax with Vray plugin, and when i try to render a cylinder with 0.0 heigjht, it get noise, well this can eb fixed by increasing the height a tiny bit. But the problem appears when i have alot of particles, of the type "facing" closet o eachother, some of them end up being in the exact same position as another one, and this creates noise or black dots... Even if the particles have opacity 0.

SO do anyone know how to fix this? And this noise appear regardless if GI is on or not.

 

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Why exactly would you make cylinder of height 0 as opposed to just a filled circle? The cylinders top and bottom faces would occuppy the exact position, which a rendering engine won't know which one to display hence you get the noisy confusion.

 

Coplaner faces is just bad modeling regardless of using vray or not, so you should try to avoid creating them.

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It does matter how i create them, cus in the case of cylinder i can increase the height, i can control it. With particles... i cant.. Cus when there are so many particles, it will occur.

I tried the bias method, it didnt work. Maybe im wrong but it was the Secondary Ray Bias in the Global Switch panel tat i changed. Dont know if it is that one.

I will look at the link you gave. Thanks

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It does matter how i create them, cus in the case of cylinder i can increase the height, i can control it. With particles... i cant.. Cus when there are so many particles, it will occur.

I tried the bias method, it didnt work. Maybe im wrong but it was the Secondary Ray Bias in the Global Switch panel tat i changed. Dont know if it is that one.

I will look at the link you gave. Thanks

 

not sure how you are setting up your particles but there is an option to "keep apart" I think it's in P-Flow. Or else it's a check box with size options under the particles modify tab. this keeps particles from over lapping and thus keeps them from getting into a "co-planer" position. Another option would be to switch from facing particles to another shape. A 3D shape for instance would have depth and have deffinition so the chance of co planer would be less likely.

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There is a really simple, though tedious solution that many production houses use: Render your particles in scan line, and your background animation in Vray. There are TONS of effects that Vray isnt very good at rendering (because they were all designed to work with Max's pathetic scan-line renderer. I render most of my animations in Vray, but when there is an effect I need (lens flare, animated clouds, PARTICLES, etc) I use the scan-line renderer, render as a .tga or .rla sequence, and merge it back with my animation in After effects. Its more work, but usually worth it in the end.

 

-Nick

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i fixed it by making the material 2 sided and increase the secondary ray bias.

I like Vray rendering more cus of the lighting looks really great.

Scanlight is also ok, but for the current animation... took 17 hours to render 17 frames... Vray did it within 6 hours with better quality. Seems like scanline is bad when there are ten thousands of particles. When Vray do it really fast. And Vray has beautiful motion blur. For external effects i use After Effects

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