Mesh : Channels

Owned by thomas (Unlicensed)
Last updated: 22 Oct, 2018 by Alex Ribao
3 min read

A channel is a fluid property, for example velocity. The fluid's channels can be used to visualize differences in the property's values and achieve realistic shading effects.

 

The "Channels" section with expanded "Channel Speed" parameters. "Vorticity" and "Age" provide the same parameters.

 

Smoothing Length Scale

This parameter blurs the vertex maps and can be used to avoid flicker, and control the mixing effect with differently coloured fluids and weight maps:

  • The parameter's range is from 0 to 10, while 10 represents the strongest smoothing effect.
  • Meshes have to be recreated when this parameter has been altered.
Velocity Color Set

RealFlow meshes change their aspect (topology) drastically between frames. This feature can put the render engine in a difficult situation when motion blur needs to be computed. In general, using a Color Set as a source for a mesh speed is a good practice because it is not necessary to query the previous and next frames to get a proper motion blur result.

The velocity values are directly encoded in the color set in world coordinates. The Motion Blur Strength parameter can be used to adjust the effect of the motion blur.

The Color Set state can be checked out with the tool located at: Mesh Display > Color Set Editor.

Velocity Color Set Name

Here you can customize the name of Color Set which will contain the mesh velocity values. The default name is rfVelocity.

Make sure the name is the same in your render engine motion blur parameters.

  • In general, click the polySurfaceShape generated by the RealFlow mesher and fill the Mesh Controls > Motion Vector Color Set parameter.
  • For Arnold renderer, fill the Arnold > Export > Motion Vector Source parameter of the polySurfaceShape.
Channel Speed

Speed represents and visualizes the different zones of velocities in the fluid.

Channel Vorticity

Vorticity is used to show the fluid's swirls and vortices.

Channel Age

This channel shows the particles' age distribution. If all particles share the same age the fluid will have a uniform colour.

Channel Weights

If the mesh contains multiple fluids or emitters you can create blending and mixing effects with differently coloured fluids.

  • From the "Type" menu you can choose whether the maps should be created from fluids or emitters.
  • For fluids, all containers have to be linked to one single mesh in order to make the maps work.

Min|Max Parameters

Min

"Speed", "Vorticity", and "Age" have a "Min" parameter. All mesh areas with channel values smaller than "Min" will be rendered with the same material colour:

  • Mesh areas with channel values between "Min" and "Max" will be rendered with shades.
  • If you don't know where to start check "Auto", and you will see the lowest current value that can be used as reference.
  • The mesh has to be → rebuild when you change the "Min" parameter.
Max

"Speed", "Vorticity", and "Age" have a "Max" parameter. All mesh areas with channel values greater than "Max" will be rendered with the same material colour.

  • Mesh areas with channel values between "Min" and "Max" will be rendered with shades.
  • If you don't know where to start check "Auto", and you will see the highest current value that can be used as a reference.
Auto

"Speed", "Vorticity", and "Age" have an "Auto" parameter. When active, RealFlow | Maya calculates the "Min" and "Max" values of a channel automatically and uses them to create the vertex maps.

  • Mesh areas with channel values between "Min" and "Max" will be rendered with shades.
  • If you don't know where to start check "Auto", and you will see the highest current value that can be used as a reference.