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byte_fx
03-04-2009, 12:54 PM
I'm doing a personal project that is all CGI and preferably al LightWave.

Most shots are exterior in generally misty/dusty atmosphere similar to the attached examples from WALL E.

Si far I've tried both types of glows and volumetric lights but haven't been able to get close to the needed effect.

Part of the problem us the lack of volumetrics for atea and linear lights. Grids of the available volumetric lights just end up overwriting each other plus they're not very good for this type of effect anyway.

Is there any way to achieve this effect in LightWave?

Thanks

byte_fx

toby
03-04-2009, 04:43 PM
What type of effect is it that you can't seem to reproduce? I just see volumteric lights :confused:

Tobian
03-04-2009, 05:09 PM
Maybe have a go with the motion blur trick http://www.spinquad.com/forums/showthread.php?t=24203 With a little thinking round it you can do a lot of cool effects...

byte_fx
03-04-2009, 07:53 PM
The problem is LW doesn't support volumetrics for area and linear lights. If you try to use volumetric point or spotlights to fake an area or linear light - with the entire light providing volumetrics - it just looks really wonky because the volumetrics originate from a single point instead of from the entire light.

And using multiple point or spot lights to spread the volumetrics out just results in the individual volumetrics overwriting adjacent volumetrics. Increased womky factor.

byte_fx

toby
03-04-2009, 08:46 PM
Ok, I was wondering what result you were after - with spotlights, you can extend the cone base, so the origin is not a point but a circle. If you need another shape, you can use a shadow object made hidden to camera.

Not sure what you mean about overwriting each other though, they are additive by default :
here I reduced the intensity of the one behind to compensate. Can you post a pic of what you mean? Have you changed the settings a lot?

byte_fx
03-04-2009, 10:50 PM
Yeah - I've been playing around with this quite a bit.

First with the spotlight base setting which kind of worked except I had to really crank down the cone angel to keep the beam from diverging to much then had to move the light too far back - actually outside of the item it's mounted in - and that caused o other problems.

Tried activating Glow under Surface properties and using a fairly large glow radius with a smallish glow percentage.

Tried filling the volume of the light beam with a bunch - between 2000 and 50000 points to use with hypervoxels. Again that kind of worked but still looked wonky.

Plus tried a bunch of different combos of the above.

Also checked Flay and emailed the Ozone folks but haven't received an answer yet - it was referenced at Flay.

It all comes back to needing true volumetric fog that lights can interact with. With that running a string of point lights down a neon tube would work. Render times would take a hit but I can throw a bunch of cores on the render farm if I have to.

I'll check the pics at spinquad if I can remember my account info - don't hang out there very often.

Thanks to all that responded.

byte_fx

Tobian
03-05-2009, 02:49 AM
Ok sorry, here's the pics with the source files.. basically just use any light types, and move a plane through space, set to be double sided/translucent and use the new PR motion blur so you capture slices of it as it moves through.. quite intensive, but then volumetric lights aren't fast to render either! :D

toby
03-05-2009, 02:50 AM
Yeah - I've been playing around with this quite a bit.

First with the spotlight base setting which kind of worked except I had to really crank down the cone angel to keep the beam from diverging to much then had to move the light too far back - actually outside of the item it's mounted in - and that caused o other problems.
Ok - how about using a distant light, it gives you a cylinder instead of a cone - unless you do need a little divergence, it could work -

byte_fx
03-05-2009, 11:48 AM
Thanks again to all responders and especially the spinquad files (I really should visit there more often). I'll check them out.

Although I still haven't heard from e-on I did d/l Ozone 3.0 PLE. Far as I can tell it's fog/haze is not true volumetric.

I did consider distant lights but haven't tried them yet.

It's a night sequence with over 80 exposed fluorescent tubes in the scene and 20+ fluorescent fixtures with the translucent white covers - I generally use area lights for those and a couple of linear lights per fluorescent tube to compensate the falloff at the ends. Sometimes I use a string of point lights instead.

The fog/haze I'm looking for is the thin nocturnal type that only shows up in fairly bright lights. It's caused fewer drops/particles than typical fog.

byte_fx

toby
03-05-2009, 03:46 PM
Ok sorry, here's the pics with the source files.. basically just use any light types, and move a plane through space, set to be double sided/translucent and use the new PR motion blur so you capture slices of it as it moves through.. quite intensive, but then volumetric lights aren't fast to render either! :D
That second one's gorgeous. I've seen this done pre-PR mo-blur and it doesn't compare. Imagine adding a 3d procedural, world coordinates with slight motion, to the transparency of the polygon :cool:

Tobian
03-05-2009, 04:27 PM
Actually I do have a procedural set to world coords in there, it's just very subtle the effect! I actually used a plane infront of the camera with a distance gradient in transparency. This does have limitations as DOF doesn't work right with it, but you could just do it the Mblur method too, in which case it would work! :D I also have a transparency gradient in the Y so it clings to the ground more. And thanks! :)

and yeah PRblur just does not compare to the old AA. One of my mates tried the same effect using pretty much the max AA on classic cam, and still it was jittery. that's silky smooth with the AS and AA of the advanced cameras... The beauty here is it works with any light type, the trick is to have the plane not be edge on to the camera. Would work on your tubular lights too, and don't forget Dpont has a 'tube' light instead of a linear light, for better Neon tubes :)

toby
03-05-2009, 10:11 PM
volumetric area lights, using the same scene, just stuck them in the fog. Sloooo-hooooow...w

But I'd consider this "true" volumetric, because there is material sampled at every point in 3d space, give or take.

Tobian
03-06-2009, 03:55 AM
haha yeah I never said it was fast, but with multiple cores it can go quite quickly and you can always turn down the quality/AA for tests. It is truly volumetric as it can cast and receive shadows.. and if you have enough passes on the Mblur actually bounce radiosity too! :D (With interpolated it only calculates a frozen state based on a time-slice, but with MC you could actually get real interaction, at a hugely slow speed!) LW could use a true volumetric fog effect, but this is about as close as you can get! :D

toby
03-06-2009, 04:12 AM
The addition of area lights, needing high light quality and raytrace shadows on top of the mo-blur is what killed it. Looks pretty badass; however, set to inverse distance^2 you get sample spots too bright to aa.

toby
03-10-2009, 12:20 AM
wheeeeeeeeeeee!

interesting thing is, the more motion blur passes you use the worse it looks; 2 is best

Panikos
03-10-2009, 01:19 AM
You can render LW Volumetrics in a black matte scene, blur them and compose them (Screen mode) over your rendered scene.

Tobian
03-10-2009, 04:39 AM
Yeah I found that too Toby, it was funny how it works like that :D Cool render! :)

toby
06-26-2009, 04:24 PM
You can render LW Volumetrics in a black matte scene, blur them and compose them (Screen mode) over your rendered scene.

:foreheads

Of course! That'll allow you to render low-quality for better speed.