Hi @RIL, i am not so fluent with GH but would imagine this is possible. Either create a component which references a Rhino object (your mesh) and give it an output of selected subobject indices (faces, vertices). Then create a component which can be run with a button to perform subobject selection or highlighting with the code in my script. I’ve tried some baby steps to show how to get highlighted mesh face indices:
SubObjectHighlight.gh (6.8 KB)
It may also be possible to create your own getter funtion for a component but that is over my head. Btw. do you run Rhino 5 or 6 ? It makes a difference in regards to persistent subobject selection, which is only possible in Rhino 6 as far as i know.
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c.