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jaf
05-19-2010, 07:22 PM
There was a discussion on a Terragen forum about differences between PC and Mac renders of the same scene. I was curious about how well or not LW does in this area. Are there real visual differences in Mac/PC renders of the same scene?

Lamont
05-19-2010, 10:57 PM
There's a whole site dedicated to LW benchmarks. Maybe you can find something here (http://www.blanos.com/benchmark/).

Lamont
05-19-2010, 11:27 PM
Hahaha, I read it wrong. My English comprehension has gone down the tubes.

accom
05-20-2010, 12:01 AM
Especailly when I'm not as think as you drunk I am!

Well, it's been a while since I rendered anything on a pc, but to my limited usage of LW, I haven't noticed any differencies - I never looked for any, true. AFAIK the only problem could be procedurals and plugins that are not existing on both platforms.

biliousfrog
05-20-2010, 04:16 AM
Certain procedurals 'used' to render differently across different platforms and even different CPU's (such as AMD vs Intel) but I fairly certain that it is no longer the case and hasn't been an issue for a number of years.

Martin Adams
05-20-2010, 04:50 AM
If you ever want to know if there's a difference, render the same scene on both machines, and save them as the same non-compressed image and compare binary data of the final rendered output. In theory, if they are equal, the file binary content should be like for like.

I have wondered though if different CPU instruction sets could round off floating point numbers with a varying degree of accuracy, which could result in a different output. But I've no idea if that's just nonsense.

jaf
05-20-2010, 11:41 AM
This is the thread on the Terragen forum:
http://forums.planetside.co.uk/index.php?topic=9882.0

The author wanted to render half of the animation on his pc and the other half on a mac.

It got me wondering how well LW does.

Martin Adams
05-20-2010, 12:46 PM
That's quite interesting. If it does come down to floating point errors building up the errors over complex calculations, it would be interesting to see if a Mac machine produced any differences between booting into OSX or Windows (using bootcamp).

kojean
05-20-2010, 03:36 PM
Not quite relevant to LightWave, but I once tried network bucket rendering a single image GI scene with an old version of Carrara across an assortment of machines, Pentium-M (mobile), Pentium III, AMD Sempron and an Intel C2D Mac.

The image came out like a patchwork mosaic of tiles where segments rendered on different machines clearly stood out from the others. I didn't spend any time trying to determine which machines were rendering differently or if they were all producing different output.

shrox
05-20-2010, 04:25 PM
Certain procedurals 'used' to render differently across different platforms and even different CPU's (such as AMD vs Intel) but I fairly certain that it is no longer the case and hasn't been an issue for a number of years.

I hated that, blamed myself for weeks until we figured that out.