To create a semi-transparent surface you can start by making a new surface or just duplicate an already transparent surface like glass..
Then add a vectorial hatch - maybe a 25% fill, and set it to use a very light coloured pen.
The transparency level of the surface will affect the 3D view.
The fill and the pen colour will affect what you see in elevations.
Make sure transparency is turned on in elevation settings and 3D style.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11