As a developer, it is currently impossible to render Highlight instances on 3D models that are placed inside a ViewportFrame.
When we parent a Highlight to a model inside a ViewportFrame, the effect simply doesn’t show up.
If this issue is addressed, it would improve my development workflow because it would allow developers to easily create polished 3D UI elements—such as custom inventory systems, item preview/shop screens, and character selection menus—with rarity outlines or selection effects. What do you think?