Select within a volume?

Hey all.

I have two things. The first is a series of vertical planes that are quite short in length. The second is a series of spheres. My hope is to use the spheres a method to select the smaller, vertical planes.

ie: Select all of the Vertical Planes that occur INSIDE of a certain sphere.

What I'm looking for is a 'select all objects inside of a given volume' component.

Any thoughts or examples? I know how to do this by intersection... but many of the smaller elements are inside of my sphere and do not intersect the outside in any way.

Example by intersection

Thanks!

JMP

Attachments:

Select_Within_Volume_01.JPG, 59 KB
Select_Within_Volume_02.JPG, 68 KB

Replies to This Discussion

Permalink Reply by David Rutten on January 19, 2011 at 1:02pm

Hi JMP,

selecting points inside volumes is easy enough. Arbitrary geometry is much harder. If you can simplify your geometry into a collection of points so that if all these points are on the inside, the base geometry is also guaranteed to be on the inside, then it's only mildly difficult.

Rectangular surfaces are relatively easy this way, you can check the 4 corner points for inclusion. However, this only works if the volume is convex (Spheres are convex, so again, you seem to be lucky here). I attached a file which tests the inclusion for all corners of a rectangular surface, then adds those inside/outside bools together to get a number representing the state (0 = outside, 1/2/3 = mixed, 4 = inside)

Another way to simplify this problem is to limit yourself to spherical volumes only. It's very easy to determine whether a point is on the inside of a sphere or not. If the distance from that point to the sphere center point is less than the sphere radius, you're on the inside. You could use this shortcut to test -say- all the points in a mesh-representation of your shape.

David Rutten

david@mcneel.com

Poprad, Slovakia

Attachments:

inside_outside.ghx, 52 KB

Permalink Reply by Shamil Katibov on September 11, 2017 at 6:32am

Hello David! Need your help.

I have a similar task on a current project in our office. We have to remove all geometry (representing facade panels) that is inside the boxes(representing window oppenings). The facade geometry basically consists of triangular planar surfaces. I broke the process into two steps. First, I was gona find surfaces that are completelly inside the boxes and remove them, but for some reason it works if only one box is added to geometry(mesh that is supposed to include surfaces).Second step is to trim the rest of surfaces that partially intersect boxes. Pictures and model+script files attached.

Why would it refuse to work with multiple breps?

Any help is appreciated.

Attachments:

Permalink Reply by Shamil Katibov on September 11, 2017 at 6:34am

more pics

Attachments:

yukuk.jpg, 349 KB
photo_2017-09-07_19-35-59.jpg, 118 KB
363AR_Грайвороново_CENTRAL_20170906_katibov23.jpg, 708 KB

Permalink Reply by Richard Schaffranek on September 11, 2017 at 8:44am

Hi,

I modified your script a bit, should work now. However there is one surface at the front which doesn't behave correctly. When I rebuild this one Surface it works...

Attachments: