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slimbolina
05-17-2005, 03:18 PM
Folks,

I'm been doing my newbie HDRI experiments resulting in the image shown below (the cat wasn't done with Sas Lite. He's real ;) ) This one was done with Montecarlo at 4x12, no AA, 600x800 pixels, and took over an hour to render.

But when I crank the same scene up to M'carlo 10x30, AA at PLD 2-pass and 1024x768 pixels and hit F9 it starts rendering ok, but at some point that is almost impossible to define it seems to go into what I guess is an infinite loop. After as much as 12 hours its still only on pass 2/2 and Window Task Mgr says that LW is 'not responding'. I've tried this several times with consistent results :(

Machine: Dell Inspiron 8200, P4 1.8Ghz, 1GB RAM, XP Home, NVIDIA Geforce4 440 Go.

Has anyone any ideas why this is proving so troublesome? The hassle seems to have started after I introduced RT reflection with refl blur into the (table front projected) groundplane. The areas with reflections really slow down when I watch them in the render preview window...

Thanks in advance,
Slim

Captain Obvious
05-17-2005, 03:56 PM
But when I crank the same scene up to M'carlo 10x30, AA at PLD 2-pass and 1024x768 pixels and hit F9 it starts rendering ok, but at some point that is almost impossible to define it seems to go into what I guess is an infinite loop. After as much as 12 hours its still only on pass 2/2 and Window Task Mgr says that LW is 'not responding'. I've tried this several times with consistent results

Err... You really shouldn't even attempt such a rendering. Set it to 4x12 or something such instead and render more anti-aliasing passes. You should be careful with Monte Carlo in Lightwave. Set it an inch too high and the render will never finish.

Oh, and blurred reflections/fractions in Lightwave's default renderer is really slow. If you take a simple sphere with a simple backdrop and render with raytraced reflections, it takes about ten times longer if you use blurred reflections (regardless of the amount you blur them). The Monte Carlo radiosity also takes a lot longer with raytraced reflections. I had one scene that rendered in half the time when I turned down the raytracing recursions from five to three. Without the Monte Carlo radiosity, it didn't really have an impact on render time.

hrgiger
05-17-2005, 04:09 PM
3 reasons:

Your machine is slow(Dont' worry, I consider every computer in 2005 too slow for 3D).
Lightwave's Monte Carlo setting (esp at 10 X 30) is very slow.
Setting multi-bounce on Monte Carlo is Extremely slow.(Especially at higher resolutions)

There is no infinite loop happening and Lightwave is probably still rendering even if your task manager says not responding, it's just most likely using up all the system resourses it can to complete the task.

Lower your ray recursions in the render options panel. It's set at a default of 16 which is much more then you need in most cases. I usually use a 4 or 5. This will help especially if you're using raytracing in your scene.

Try lowering your bounces back to 1 and use some additional lights in the scene to simulate bounced light.

You could also try using the interpolated or background only forms of radiosity but it will require some trial and error to get the quality you want vs rendertimes.

slimbolina
05-17-2005, 05:46 PM
Thanks guys,

Good to know I'm not going mad! I'll see if I can render it in parts so that no one is too much, and bung them together in Photoshop.

TTFN,
Slim