Wispy Smoke A shelf tool

Creates a medium scale wispy smoke simulation that rises upward smoothly.

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Important Nodes
Learning from this example

This shelf tool sets up a sparse pyro simulation of medium scale smoke. Rather than building a DOP network, it uses the SOP-level tools to build a simple network to work with sparse pyro. The smoke simulation consists of a static source, emitting smoke straight up into the air without a lot of movement until the smoke has been around for a while.

Pyro simulation in the viewport. Color space: ACES, Voxels Size: 0.01.

Pyro simulation rendered with Karma. Color space: ACES, Voxels Size: 0.01.

This shelf tool generates a wispy smoke simulation with controls for creating the Mie Scattering effect seen in real world reference.

Important Nodes ¶

advect_soot_particles

advect_soot_particles is used to advect points using the velocity field from the wispy smoke simulation. Those points are given a density attribute that can be modified and is then turned into a VDB named gradient used in the shader. Play with the parameter controls at the top level of this solver to fine tune the output particles.

scale_density

By default, burn is sourced into the flame field in the pyro simulation. The flame field is then output and used alongside the temperature field to scale density post simulation and create more transparent smoke closer to the source. This happens in the scale_density nodes. There are two of these in the setup.

Learning from this example ¶

To...	Do this
Change the shape of the wispy smoke	Dive inside pyrosolver1 to adjust custom forces in nodes like gaswind1 and gasvelocityscale1.
Switch between Mie Scattering approaches	Create a `gradient` VDB using the advected soot particles. Calculate the gradient of density from the wispy smoke simulation, calculate the length of that gradient field, and then remap that in volumewrangle1 to more user friendly values. Use switchif1 to switch between the two methods.
Adjust Mie Scattering effect in the shader	Control the brightness using the Intensity Scale parameter in the Fire tab of the pyrobakevolume1 node. The `gradient` field is used to control the density and color of the smoke in the lopnet1 shader.
Change where Mie Scattering Occurs	Use the attribremap1 node to remap density and control where Mie Scattering occurs, if using the particle approach. If using the VDB approach, you can control this effect in the volumewrangle1. Note The VDB approach is a bit faster, while the particle advection method will give you more control.

Wispy Smoke A shelf tool

Important Nodes ¶

Learning from this example ¶

Shelf tools

Using the shelf ¶

Technical ¶