Shading one variable with the values of another (volume rendering)

Hello, new Paraview user here. I’m a long time user of VisIt and do a lot of volume rendering (I simulate tornadoes/thunderstorms). I’d like to be able to volume render one variable but color it with the values of another variable. With VisIt, in the Volume plots attributes panel at the bottom, there is an “Opacity variable” option that enables this. What I wish to do is volume render vorticity magnitude, but I want to shade it with one of the components of vorticity. Since I model tornadoes, this can show me which way things are rotating (clockwise/counter clockwise) about a vertical axis, but also show horizontal vorticity.

An example of what I want to do is here:

There are “red guys” and “blue guys”. The full vorticity magnitude field is volume rendered, but I’m shading it with the vertical component, with negative (blue) indicating clockwise rotation about a vertical axis, and positive (red) indicating counterclockwise rotation.

Can Paraview do this? I’m trying to get away from CPU based volume renderers as I have a nice big fat NVIDIA GPU that needs a workout :slight_smile:


The only thing that is remotely similar in ParaView is the multi component mapping volume rendering.

@Michael may have other ideas.

For what it’s worth, making opacity mapping by a different scalar array much easier is planned for implementation next year.

Cory, that’s great to know. Mathieu, I will check out your link and give it a shot. Thanks.

Hello again, checking if this functionality of being able to shade one volume rendered field with another field has been implemented yet.

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Hi Leigh,

Opacity mapping by a separate array was just added to ParaView and will be available in ParaView 5.9, due out in early September 2020.