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ddeath
03-31-2011, 06:52 AM
hi, may i know how to increase the thickness of smoke? I tried increasing viscosity and tried tweaking the uniform division but to no result. Can anyone give me some advice? thank you.

rjw
03-31-2011, 03:15 PM
If you used the Shelf to add the source or one of the four Pyro set-ups, you can go to the Apply Source DOP and crank the Emission Amount to what ever value you like. Note that the emission of smoke also adds temperature.

The Smoke Solver doesn't have an overall Emission amount scale parameter but the Pyro Solver does. In the Pyro Solver, in the Sources/Emitters tab, you can increase the Smoke Amount parameter. This will scale all the source emission rates in your simulation.

The higher the emission rate, the more temperature you add, the faster your smoke may rise. If you want the sim to behave the same or similar after cranking density, you should either cut back the smoke emission temperature in the Apply Source DOP or cut back the Buoyancy Lift in either the Pyro or Smoke Solver to compensate.

It is also common to scale the density field in Geometry SOPs in the Smoke Object. This is a post-simulation change adjustment and is non-destructive to the sim at all. Append a Volume Mix SOP, change to User mode and in the expression, you will see $V for the current voxel value. Multiply this by any factor to make the density field greater or less. $V*10 will increase the density by 10 times. This is handy if you wish to send scaled densities for rendering and not rely on density scaling in the shader itself.

rjw
03-31-2011, 03:19 PM
If all you want to do is simply change the display of the density field in the viewport while in DOPs, you can also go to the Smoke Object and change the visualization display settings for the density field.

On the starting Smoke Object DOP, go to the Guides/Density tab and simply crank up the Smoke Density parameter. This won't change the simulation one bit and is equivalent to post-scaling the simulation density field with a Volume Mix SOP or in the shader density setting at render time.

Lots of flexibility.

fomal
03-31-2011, 04:41 PM
There are many things you could mean by thickness. This can either be related to the viewport visualization or simulation. Do you want it move slower or appear thicker?

Using a primitive sop you can vary the thickness in the view port (under volume settings). This can also be changed in the shader when rendering. To make it move slower, play with buoyancy, temperature diffusion and cooling rate. Make sure to read the help on how these parameters relate. They all scale relative to temperature.

ddeath
04-01-2011, 06:08 AM
There are many things you could mean by thickness. This can either be related to the viewport visualization or simulation. Do you want it move slower or appear thicker?

Using a primitive sop you can vary the thickness in the view port (under volume settings). This can also be changed in the shader when rendering. To make it move slower, play with buoyancy, temperature diffusion and cooling rate. Make sure to read the help on how these parameters relate. They all scale relative to temperature.

I want the smoke to be thicker in volume. How cooling rate works?

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