New and having issues

Have been using Ashlar Cobalt for years but they went to subscription so I got Rhino 7. My main issue seems to be that when I create a solid and then trim a part out of it, what I thought was solid is suddenly hollow. Second issue is that Cobalt was head and shoulders above Rhino on the snap to thing. I find that I can no longer just grab something I drew and snap it to something I drew before…I have to select it and command MOVE and then click a corner point and try to then click where I want it. But always where I want it says “PROJECTED END” and it will not snap there at all.

So I drew a simple part of something here, and then exported it as a stl and loaded it into Meshmixer to examine. Meshmixer finds all kinds of errors and when it tries to repair it it deletes parts of it. Wondering if I made a mistake with Rhino at this point…
1.stl (9.6 MB)
Side.3dm (1.4 MB)

Some of your parts are open polysurfaces and missing faces. You can close most of them with the Cap command.

Two open polysurfaces remain. I suspect you didn’t use boolean difference to create the cutout for the window frame…

I’d suggest to create a box on a separate layer and use a dedicated color so you easily see what needs to be subtracted:

Side.3dm (3.0 MB)

Oh and regarding the snap, I think you had Project enabled where all snaps are projected to the current construction plane.

So in this program, when you subtract(trim or slice) something from a solid it becomes a tube with a cap at the other end? And you have to then cap the end you cut from to make it a solid again?

Check this please:

Rhinoceros Help - BooleanUnion | Rhino 3-D modeling (

I have been playing with that and I see the difference. 1 more question for now, what is the best way to create a solid of irregular shape. Srfpt and then extrude or create a box and then the create the shapes you want to subtract and booleondifference?

In your case you can create a surface or closed curve of a section of a part and then linear array it to create the copies.