Smoke Shader ?

[bernhard]

Does anybody know how I could create a simple smoke shader when using sprites as particle render type ?

thx for any good idea,
bernhard

[ricorio]

Sprite Shader ? Just assign a vray material and use a smoke file texture with an alpha map. If you use a bunch of smoke images you can do a random assignement to the sprites (there are several tutorials out there on how to do this).
To get the smoke images you could use maya fluids and render them with MR.

Hope this helps.

[bernhard]

I use a simple particle emitter - for the shape of the particle I use sprites (planes are facing to the camera).
For the opacity I use any kind of ramp (radial), mixed with a cloud map or some smoke maps - that's fine so far --> except the render time with the opacity map.

But I still would need some kind of falloff for the particle itself - smoke has a much higher density at the source and get's thinner and thinner till it disappears.
Kind of Particle Age Map for the Vray Opacity slot - unfortunately I can't find such a map in Maya.

I also couldn't find any tut you mentioned - but if you do have a link, that would be great.
Thank you very much for the hint with the maya fluids and mr, but I want to use Vray only.

[pechart]

Take a look at the particleSamplerInfo node in maya. From there you can pipe out a lot of things, regarding the particles in your scene. It can be found in the hypershade, under utilities -> particle sampler. But I don't know which attributes vray supports.

[ricorio]

'Kind of Particle Age Map for the Vray Opacity slot'

you could try this with an expression ... somethink like this:

vrayMat1.opacity = something / particle1.age;

this probably never gets you to zero ...

so put a if statement like

if (particle.age >= theAgeTheParticlesAreCompletlyGone)
vrayMat1.opacity = 0;
else
vrayMat1.opacity = 1 / particle1.age * scaleTheOpacityEffect;



the image sequence random assignement must be somewhere in the help files.

[tinuz]

so you need opacity per particle based on it's age?

go to particle shape:
click on opacity un add dynamic attr
add per particle
right click in empty line behind Opacity PP
choose Create Ramp, option box
by default this maps a ramp to the age..
voila..

[bernhard]

thx to all of you, highly appreciated ! It worked for me best with the suggested method from tinuz - thank you very much !