Create edgy smoke

[Nerox]

Hi Guys,

I'm just playing around with the wispy smoke and the result I got so far is very nice, but jet it's a bit soft or smooth compared to smoke in reality. I can remember there is a method to sharpen the sim, like the edges between smoke and no smoke area's. I might be wrong but as far as I can remember there was sort of a mathematical way of 'collapsing' the edges to make them more sharp.

Maybe I'm talking rubbish, but ... any bells?

Nick

[Overload]

Hi Guys,

I'm just playing around with the wispy smoke and the result I got so far is very nice, but jet it's a bit soft or smooth compared to smoke in reality. I can remember there is a method to sharpen the sim, like the edges between smoke and no smoke area's. I might be wrong but as far as I can remember there was sort of a mathematical way of 'collapsing' the edges to make them more sharp.

Maybe I'm talking rubbish, but ... any bells?

Nick

Try using the VexPyro shader, and mess around with the Contour and Soft Clipping parameters. You'll need to setup a density modifier. Cheers.

[ikarus]

well what you are essentially describing is clamping density values in a uniform matter where every voxel contains either a value of 1 or 0 for density. This looks bad, obviously, unless at extremely high divisions.

For a cheaper effect all you need to do is blow out the density value in your smoke shader.

What that smoke "density" value does is act as a parameter which is thrown into the equation:

den = max(den, 0);
        Of = (1 - exp(-den*dPdz));

den being the parameter (assuming that you are using one of the built in volumetric shaders)

that equation acts as a log function which carries the density values in the voxels infinitely close to 1, based on the variable input

or you could just increase uniform divisions

[pencha]

If using the pyro shader, You could create a density modifier and manipulate the curve (maybe I´m just saying the same than Overload, not sure if the curve was called contour).

You could also do it with a volume vop and a ramp or a function too, depending on what´s your need.

[Jason]

You can also try change the Volume Filter to something like "Blackman" or "Sinc"

[essencevfx]

hows your volume step size ? try and lower a bit, other than that , usually more res, combined with what the gents above have mentioned.

good luck

[goshone]

Another trick I found helpful was to use the ramp widgets under the temperature tab in the Billowy Smoke shader (assuming that is what you are using). You can change the 'Temperature Field' to density, and adjust the ramps similar to the way Maya fluids work (for sharp edged smoke give it a sharp falloff on the left hand side of the ramp). This would only work if you don't actually use temperature for shading.

good luck

G1