Select objects on either side of a cut plane?

Rhino
1

Let’s say I have a model of a building which I have just cut in half using a plane, and I want to select everything to one side of the cut plane using a command, rather than selecting everything. Is there a way to do this?

Thanks
Paul

2

Hi Paul - off hand, I can’t think of a simple way to do this with existing commands but it is a reasonable thing to want to do, I’ll put it on the pile, & try to cook something up the the short term.
@pdfaze - here’s a start - there is more to do - like handle objects that intersect the plane, different ways of specifying a plane etc but for now, select a planar surface or curve, click or use the option to toggle the side selected.

SelPlane.py (8.3 KB)

To use the Python script use RunPythonScript, or a macro:

_-RunPythonScript "Full path to py file inside double-quotes"

-Pascal

1 Like
3

Thanks for the quick reply, Pascal. Haven’t quite gotten it to work yet. Here’s my file for reference.

Best,
Paul
SelectCutPlan Test File.3dm (9.9 MB)

4

Hi Paul, this works here but the fly in the ointment is that I have not yet worked out the best way to deal with objects that touch or intersect the plane - so some objects in your file are missed.

image
image482×970 70.2 KB

Do you get no action at all, or the incomplete result?

-Pascal

5

Incomplete results, similar to what you’re showing. It seems like maybe the issue is with objects touching the plane, as you said.

6

Hi Paul - just touching I can probably deal with - at least I can usually make a decision about which side they are on - how should intersecting objects be handled? Always selected? How about coincident planar objects?

-Pascal

7

Hi Pascal, I imagine intersecting objects would not. This way if an object didn’t split you would leave it behind and it would be easy to notice, but yes to select coincident planar objects.

I don’t have strong opinions on this but that’s what I imagine would work best for my workflow…

8

Hi Paul - updated above to get just-touching objects that are on one side or the other of the plane. Completely coplanar objects are currently put in one bucket and not both, it will take a bit more fussing if these should always be selected.

@pdfaze coplanar objects should now be included in either selection. Intersecting objects can be selected or not accortding to the ‘Crossing’ option. Updated above.

-Pascal

9

Thanks Pascal, this is perfect