Render geometrical boundaries with uniform color

[aroccaPrediqtt]

Hello,

I'm trying to render a scene where solid boundaries (e.g. an airfoil surface) appear with a uniform, constant color, while the volume is visualized using a scalar field (e.g. Q-criterion), similar to the following:

At the moment, the only approaches I found are:

• using a separate topology for the boundaries and rendering it with a mesh plot (which gives a solid color but limited control compared to pseudocolor), or
• defining a dummy constant field on the boundary and using a pseudocolor plot.

Both approaches work, but feel like workarounds rather than intended solutions.

I also came across a related discussion: #1113

My question is:
-is there a recommended or more native way in Ascent to render a topology with a uniform solid color, independently of any scalar field?

-More generally, would supporting a "constant color" option for pseudocolor plots (or a dedicated surface plot) be aligned with Ascent’s design?

Thanks in advance!

[cyrush]

@aroccaPrediqtt here is another related issue #1027

Right now a fake field with pseudocolor and custom color table is the way to get this done.
We would like to make this nicer.

We can look into making this an option to the mesh plot.

[dmhensi]

Please provide a set of standard colors that can be provided instead of a field for pseudocolor.

[dmhensi]

Could this be done using pipeline expressions? I'd try this but I haven't got OCCA.

[dmhensi]

I've been able to create what I want for the coloring of threshold pipeline output by creating an element field that encodes the material ids. How can I avoid having the multiple color tables. Yaml file content below.

- 
  action: "add_scenes"
  scenes: 
    s102:
      plots: 
        p1:
          type: "pseudocolor"
          pipeline: "pl102"
          field: "matid_color" 
        p2: 
          type: "pseudocolor"
          pipeline: "pl103"
          field: "matid_color"
      renders: 
        r1:
          camera: 
            azimuth: 0.0
            elevation: 270.0
          image_prefix: "ALL_VF_IMAGE"
          dataset_bounds: [0.0, 0.064, 0.0, 0.064, -0.06, 0.068]
- 
  action: "add_pipelines"
  pipelines:
    pl102:
      f1:
        type: "threshold"
        params:
          field: "VOLUME_FRACTION_HZB STEEL"
          min_value: 0.001
          max_value: 1.0
    pl103:
      f1:
        type: "threshold"
        params:
          field: "VOLUME_FRACTION_WHA"
          min_value: 0.001
          max_value: 1.0

[nicolemarsaglia]

Unfortunately, I don't think we can combine color bars. The most you can do is disable one of them. I'll make an issue ticket about combining color bars: #1734

[dmhensi]

That would be great. In a similar case where a scene contains two plots each of which uses a different pipeline that contains a "vector_magnitude" filter the resulting image has a single color bar.

A filter that provided a "constant_value" for all output from an upstream filter might be a way to color pipeline output.