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jasonwestmas
02-28-2009, 12:06 PM
Would someone be so kind as to tell me how I would go about blurring the edges of the volumetric lights, there doesn't seem to be a feature for it. I've never used V-Lights before.

Thanks for any guidance.

IMI
02-28-2009, 12:19 PM
I don't know if you can, but you might try some kind of texture within them, with gray at the edges of where you want the rays, so it isn't so harsh. Sort of like the transparency mapping deal. I'd assume values that aren't pure black or white wouldn't block or allow all light to pass through. The gobo effect with an edge falloff.
Just a guess though, really, and wouldn't help where the shadows come off an object.

EDIT:

That's one evil looking character there!

IMI
02-28-2009, 12:52 PM
Just did a quick test and you can soften that shadow some if you duplicate the volume light and offset it slightly from the first. Of course, the render time goes up.

Or, the "spinning light trick" might be worth looking into.

jasonwestmas
02-28-2009, 02:11 PM
Thanks IMI, I tried a cloud texture with "Texture only" checked and the light inside a light deal, but the edge is still pretty hard. Though it looks better. I forgot what that spinning light trick deal is. Is that PRM Blur with an animated spin on two axis?

P.S. yeah she looks like she's from mad max or something ;)

IMI
02-28-2009, 02:24 PM
Neat video by William Vaughn on the spinning light trick:

HERE (ftp://ftp.newtek.com/multimedia/movies/w3dw/spinlight.mov). Right click, save as...

It's rotating a light 720 degrees with a slight wobble on the bank over the course of a fractional frame. It simulates the effect of area light shadows or GI shadows in a still image or an animation. And yeah, you need MB on it as well as AA.

Having said that, I think another option might be GI, since it would fill in some of the harshness of the shadows.
Although it hurts me even just to think about volumetric lights and GI rendering in the same scene. ;)

jasonwestmas
02-28-2009, 02:36 PM
Neat video by William Vaughn on the spinning light trick:

HERE (ftp://ftp.newtek.com/multimedia/movies/w3dw/spinlight.mov). Right click, save as...

Having said that, I think another option might be GI, since it would fill in some of the harshness of the shadows.
Although it hurts me even just to think about volumetric lights and GI rendering in the same scene. ;)

Awesome, I'll take a look at that.

Yeah I usually work with deforming meshes anyway so the Lightwave GI is a little out of touch with what I want to do. I tend to make up for lack of GI using reflection blur on everything, 6 or so area lights with ambient, little luminosity etc. I want to create more atmosphere with fog and volumetric lights to simulate particles in the air which is why I'm looking into this now.

IMI
02-28-2009, 02:44 PM
To tell you the truth Jason, I've never had much luck with LW's volume lights either. IMO, they've always been more trouble than they're worth. Too bad we can't have volumetrics with area lights- that might be alot better.

jasonwestmas
02-28-2009, 03:35 PM
Yeah, the V-Lights would be fine if I could get rid of that stupid edge. I mean it looks more like a glass volume than a light bouncing off air particles, sheesh. Know of any plugins that may give me a lighting effect? Maybe I can create a volumetric object or something that is soft looking and emits light.

IMI
02-28-2009, 03:54 PM
I don't know of any plugins, no.
Some kind of cloudy, foggy HV particle cloud might give a reasonable atmospheric effect, and if it has luminosity it would emit light in GI (with volumetric radiosity turned on in the render globals panel), but I very much doubt it would cast the kind of volume shadows you want, if even remotely close.
"God rays", I think people call them now. You might want to look more towards Vue or the Ozone plugin for LW to do such a thing.

toby
02-28-2009, 08:03 PM
I've been using a vol light for a lighting challenge scene, and with monte carlo it's still fast on my old g5, about one minute (radiosity settings too low for animation of course)

It would take more than 3 times longer, except I had the audacity to use a shadow map instead of raytrace shadows - I know, insane isn't it :p Raytrace shadows with volumetric lights is usually a big waste of rendertime.

You can blur the edge of the volumetrics with the Soft Edge Angle if you're using a Spotlight, and blur the edge of the shadow with the Shadow Fuzziness setting, if you use a shadow map.

jasonwestmas
02-28-2009, 08:54 PM
Sheesh, I didn't even know that the soft edge angle option worked in Raytrace mode in 9.6. Silly me. Well anyway, This is closer to what I had in mind. I'm just not sure why the lights fade out so early, the height setting on the light cone seems to have no effect.

Thanks Toby.

toby
02-28-2009, 09:05 PM
You want to turn down or off the Attenuation value - another word for falloff... why I don't know, maybe cuz they used falloff already.

There's still some things I'm trying to figure out - I'm trying to get my shadow edges more visible :

I'll probably try a projection image for the god-ray effect too.

jasonwestmas
02-28-2009, 09:12 PM
Yeah, I'm not understanding the volumetric shadow stuff either. But I'm starting to get the desired lighting effect. If I just use Inverse Distance I can extend the fade so it doesn't happen so sharply. I added a texture on the foreground light too. Pretty cool actually and it renders fast enough.

toby
02-28-2009, 09:27 PM
Oh I didn't realize you had falloff on the light :) Falloff assumes that the light source is somewhat close, so if it were sunlight you wouldn't want it.

I think my shadow just has too much vol light and fog behind it. I have to either reduce that somehow, or see if I can get negative value in the shadow or something

IMI
02-28-2009, 09:49 PM
It would take more than 3 times longer, except I had the audacity to use a shadow map instead of raytrace shadows - I know, insane isn't it :p Raytrace shadows with volumetric lights is usually a big waste of rendertime.



I didn't even know you could use shadow maps with volume lights. Maybe I was thinking about transparency.
Anyhow, thanks for the info. :thumbsup: