Polygon extrusion coloring according to different elevation values.

Nobody has claimed this yet.

**mapbox-gl-js version**: Latest

### Question

I truly appreciate Mapbox's push to support 3D visualizations. It's very performant compared to other 3D map engines.

I was trying to color the polygon's extrusion based on elevation values, but I don't think it's possible. I want to use the same polygon, but the colorset is segmented into two based on a reference value, for example blue and green. There can be multiple regions inside the polygon which can belong to either blue or green segmentation. Is there a way I could achieve it?


If I cannot implement it with the current API, I plan on using mapbox custom layer API combined with ThreeJS. Could I use the elevation data in present the elevation tiles and create such an outward projection which cuts off along the boundary of the polygon and provides the necessary color segmentation?

### Links to related documentation
- https://docs.mapbox.com/data/tilesets/guides/access-elevation-data/
- https://labs.mapbox.com/education/thematic-map-types/3d-extrusions/

Start with the linked access-elevation-data and 3D-extrusions documentation, then review the custom layer API and ThreeJS approach described in the issue. Determine whether current elevation tiles and polygon extrusion styling can support threshold-based color segmentation; done means a documented supported path or a clearly recorded API limitation.

Written by the indexing model from the issue text.