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View Full Version : Rendering animation on Intel/Amd, any flickering ?



JML
07-29-2005, 01:46 PM
we have intels in our renderfarm, and thinking adding more later.
I'm wondering could we had amd processor if we wanted to ?

the reason I ask is because I heard when rendering an animation, you could see flickering because each processor have different way to compute random numbers.

is it still an issue with current LW?
does this affect all 3D software, or can it be fix by programming.

just wondering,

Lightwolf
07-29-2005, 01:58 PM
we have intels in our renderfarm, and thinking adding more later.
I'm wondering could we had amd processor if we wanted to ?

We have a mixed renderfarm and haven't had problems... but...

the reason I ask is because I heard when rendering an animation, you could see flickering because each processor have different way to compute random numbers.

The reason is a myth. All renderers use pseudo random numbers, basically a mathematical function that returns something like "perlin" noise and can be repeated with the same input value. Which makes sense since if you had true random numbers, you couldn't render two identical images on the same machine either.
There are however miniscule differences in the way floating point numbers are evaluated internally, not only from processor to processor but also from instruction set to instruction set (i.e. using the fpu vs. using SSE2).


is it still an issue with current LW?
does this affect all 3D software, or can it be fix by programming.

From what I've gathered so far, a couple of the procedural textures may have some issues on different processors (I think someone mentioned the smoke procedurals). But basically this can be circumvented (I wouldn't dare say fixed ;) ) by careful programming.

You're fairly safe with the standard included procedurals though, especially the "older" ones like trubulence, fractal noise etc...

Cheers,
Mike