#972 Make levels groupable

[Twonky]

I use levels to categorize, sort and group objects, including dimensions, walls, rooms, polylines as guide lines etc, eventually finding up to 80 levels per project (from real estate to several house levels to interieur).

What I miss is the ability to combine levels to a group, to more easily enable/disable visibility of several levels at once. This would realize a "view" function to a project.

[ikarias]

I agree. The tool is great, but I also was surprised that there is no more hierarchy. If you you this plan with serious intentions, you will either be overflooded with objects and/or need to constantly export SVG files to other tools. For example, I currently work on a a house with a quite complicated architecture. Even though I have everything readily available in SH3D, I need to use other tools for network planning, electrics, etc.
Even if I do this in several levels on same elevation, my project looks completely cluttered.
It would be expanding SweetHome so much if you could add a layer concept like Inkscape, Photoshop, etc. Managing visibility via a side menu like this would be really a big step in usability.

I hope the developers that did not intend to do this in the last 10 years might reconsider their position.
Otherwise great tool!