Rotating the working plane/flattening geometry? (AutoCAD 2014)

Is there a way to rotate the plane you're working on on the fly? I have (what is supposed to be) a 2d floor plan with multiple elements that have non-zero z values, a lot of which apparently cannot be exploded, or sliced (after turning them to surfaces), or anything else. I tried to simply "stretch" the non-zero z vertices down/up to the xy plane and the whole object moves up or down instead. (I'm also using a LISP routine by Lee Mac to do the actual flattening after the fact).

So, what I want to do is simply draw in the 2d geometry necessary to project the object onto the xy plane, and then delete the extraneous 3d lines/objects. However, I'm working on an isometric view (to make sure I'm drawing them in at z = 0), and AutoCAD apparently thinks I want to draw "walls" (yz plane) instead of "floors" (xy plane), if that makes any sense.

Is there some button I can press to change the working plane on the fly? I have no idea why AutoCAD wouldn't have this sort of functionality when a much simpler program such as Visual can do it (just by hitting TAB you can swap between the xy, xz, and yz planes).

Alternatively, does anyone have any other suggestions for my problem, i.e. flattening geometry that does not want to be flattened?

Thanks in advance.

Why don't you attach a copy of the DWG file to your next post so we have a better idea of what you are dealing with. Visual aids are so much easier to understand than words. Thanks.

I don't find changing UCS in AutoCAD difficult at all. (Dynamic UCS, Selectable UCS icon, View Menu / View Ribbon / View Toolbar, Named UCS's etc.) but I too am not sure what type of drawing you're working with, or what you're trying to flatten.

I figured it out, though through no doing of my own, heh. I switched to a different view, then went back to SW Iso, and all of a sudden the rectangles were being drawn on the correct plane.

Still, I'm curious as to what I might've done to make that happen, or hopefully get an answer just for future reference.

Unfortunately, however, I don't think my bosses (or the client) would be too happy if I uploaded the floor plans onto the interwebz to be perused by strangers all willy-nilly, so I'm sorry for not being able to better describe the situation.

Most of the offending geometry ended up being rectangular hexahedra (i.e. 3D rectangles) that couldn't be exploded, sliced, or stretched for whatever reason. There was also an object that resembled a block of sorts (something like a 3D hatch, perhaps?), but again, I couldn't explode it.

Maybe it is just a case of not knowing how to orient your UCS.

It sounds like you should enable DYNAMIC UCS just hit F6, or turn it on at the icon at the bottom of your screen.