Highlight
Adds a coloured background region behind part of the setup, without affecting any rays.
Open in the canvas →In the real world
Shaded regions in optical diagrams can identify a subsystem, distinguish experimental stages, or mark an area of interest. Such visual grouping has no physical optical meaning unless the caption explicitly assigns one.
In OpticalSetup
Resize and position the highlight behind the components you want to group, then choose its appearance. It remains behind both rays and elements, so the beam path and hardware stay visible. Use a text label to explain what the shaded region means.
The example marks the lens area on a simple bench. Move or resize the highlight across the incoming and outgoing beam to confirm that only the composition changes.
A highlight is diagram-only. Its color and shape do not represent refractive index, absorption, an aperture, or a boundary between optical media.