Wispy Smoke B shelf tool

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

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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. Wispy Smoke B is designed to be a more turbulent version of Wispy Smoke A. The smoke simulation consists of a static source, emitting smoke that is turbulent immediately and expands outward.

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 turbulent 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 initial expansion and shape of wispy smoke sim	Dive inside the pyrosolver1 and use create_divergence1 to control initial expansion of the sim. Divergence is created from temperature and density fields. The higher the temperature and density, the higher the divergence.
Control the amount of turbulence	Adjust the Turbulence parameters in the Shape tab of the Pyro Solver. Turbulent movement is also affected by the create_divergence1 and gasvelocityscale1 DOPs inside the dive target.
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 B shelf tool

Important Nodes ¶

Learning from this example ¶

Shelf tools

Using the shelf ¶

Technical ¶