Volumetric smoke

[HowardM]

lol, yea its called Deep Shadows in Renderman... ;)

im sure you could fake it with a few sets of sprites shaded lighter or darker...

[brassi]

i strongly recommend you to get "maya techniques exploring particles" DVD if it still -exists.

the workflow, Daniel following is not only resulting such a volumetric feel,but also giving detailed information on, how one can prepare the scene for later comp stuff for having shadows on sprites.
it is pretty stunning.

and also search for kari brown in this forum. in his web page there is another sprite solution tornado and it is pretty good. he is giving little details also.

and...never underestimate the power of sprites,unless you have lots of computers connected to each other.

cheers!!!

[thomwickes]

exploring particles is amazing. that and 'particles for visual effects' have been re released. they're both really well put together and well explained. I couldnt reccommend them enough.

[Venkman]

Anyone have some links for me? I'm curious to grab these.

[thomwickes]

http://www.kolektiv.com/

get it!

[Venkman]

http://www.kolektiv.com/

get it!

Thanks! I actually just got that link from the Maya high end list.

They have particles for visual FX there, how about "exploring particles"?

[thomwickes]

they've combined the two now - the "Particles - Visual Effects Series" is adrian grahams dvd and daniel roizmans dvds.

they're both really good.

[steffenoid]

Here is a link to exploring particles:

http://www.journeyed.com/itemDetail.asp?itmNo=84441059N

It worries me that this seems to have been a piece of official Alias training material, but I can't find it anywhere on the autodesk website (maybe it's outdated or there's a finite supply).

Anyway, thanks for the responses!
I'll check all of these out.

-Steffen

[thomwickes]

As I said - its part of the bundle on the kolektiv website.

The dvd is made by the kolektiv and was originally released through autodesk - the only place to get it now is through the kolectiv the "Particles - Visual Effects Series" is both "Exploring Particles" and "Particles for Visual Effects" combined

[Venkman]

Thanks everyone for clearing that up. Sounds like a fun DVD.

[tauism]

hi steffen, you can get that look pretty easily in maya.
use particle cloud, then put a light in the scene, turn on raytracing and voila! you get shadowed particles.

make it look nicer by tweaking the settings and using a blob map.

almost "magically make smoke beautiful" button easy!

[azshall]

... almost "magically make smoke beautiful" button easy!

at the magical expense of crappy render times via casting raytraced shadows through volumes! :)

[thomwickes]

Yeah i'm loving sprites for now - I quite like hitting render, going to make a cup of tea, and having the sequence complete by the time I get back :)

[azshall]

i'm going to look at trying to write a sprite script to help fake volume/shadows by taking a percentage of the sprites, based on their size/etc and having another sprite emit just barely offset of it as if it were reacting like a shadow... and travelling with it, .. not 100% full proof but might prove to be interesting..


Seth

[tauism]

heh hehe, you can't get something for nothing, even if it is magic! that would be breaking the laws of thermodynamics! gasp!


anyway, would love to see how your script looks like when you're done with it.

[steffenoid]

Thanks everybody for your responses.

Let me know how the script goes, seth. I'm curious to see what you have in mind.

Thanks,
-Steffen

[azshall]

Let me know how the script goes, seth. I'm curious to see what you have in mind.

I'm getting some interesting results actually.. Pretty cool. Its definitely a bit on the advanced side but seems to be working better than I had expected.

Just working out some kinks on the expressions, its not "script bound" yet .. More of a proof of concept with simple textures in a simple scene to see if it will even work...

Seth

[tauism]

by the way steffenoid, particle illusion has very nice sprite based volumetric smoke. i think what they do is to start with a very nice sprite image that has the volumetric look already.

check out www.wondertouch.com for examples.

[thomwickes]

how quickly does renderman handle sprites with deep shadow? anyone know of any examples i can see?

[azshall]

how quickly does renderman handle sprites with deep shadow? anyone know of any examples i can see?

Best example I know of is the Balrog from Lord of the Rings :) ... As far as speed, its not that fast, unfortunately... But it works.

Seth

[Als]

The thing with the RFM and renderman is that you can setup up the quality parameter, which then gives you faster render time. So you tune the rendertime as much as you need and hopefull still get decent result.
I've done smoke with particle sprites, and while they look ok in view they are considerable problem to render. I ended up rendering them on a green background, so that compositors can use them.
With RFM they looked loot better with depth shadow and all, but it was not really very quick.
I hope I will get time to post a frame or two...


Als

[thomwickes]

thanks als - would be good to see some renders

[HowardM]

not fast but - http://forums.cgsociety.org/showthread.php?f=86&t=155001

[thomwickes]

yeah studied that thread a few times - I still can't seem to get results that I prefer to sprites. Can't seem to get a decent fade out on my particles with opacityPP plugged into transparency - not sure if there's a better way. I've looked at the overburn examples quite a bit but still can't seem to get what I want

[thomwickes]

this looks like a pretty cool sprite setup:

http://kbrown.wolfenstein.org/pages/posts/four-tornados34.php

with the lighting setup being written into the runtime expression of the particles.

Might have a go at creating something like this... i'm guessing you're linstep adjusting the the rgbPP of the sprites based on their distance from a locator... anyone else done something like this before?

[swampjesus]

It depends what you are at - for tornado or similar you might use curve in the middle and 'closestPointOnCurve' node to get the particle 'normal' and calculate the lighting with dot products etc.

Daniel Roizman described a way to shade particles in siggraph2002 maya masterclasses. "You simply take the position of the particle, and compare it to its position when it was born, birthWorldPosition. Based on how much the particle has moved in height from its birth position, you calculate a value. The higher the particle goes, the greater the value, the lower it goes, the lower the value.". And use red and blue channels for that.

It would be nice to get deep shadow maps to work in maya but as long as we are stuck with old fashioned hw rendered sprites. I guess mrLiquid does work with those?

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