Question about volumes of open Breps

Why does the volume component return two thirds of the correct volume for an open Brep as opposed to a closed one of the same dimensions?

I know it is the same behaviour in Rhino but at least there is a warning in Rhino. Could the Volume Component turn orange and display a warning balloon when handling open Breps?

I've just spent a bleary eyed 30 mins trying to figure out where I'd gone wrong.

Replies to This Discussion

Permalink Reply by David Rutten on August 15, 2011 at 5:02pm

I don't know why the result is 2/3 of the actual volume. Is it always exactly 2/3, no matter what the shape?

Anyway, I added a warning for open meshes and breps:

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Danny Boyes on August 16, 2011 at 1:09am

thanks

Permalink Reply by Danny Boyes on August 16, 2011 at 2:53am

Sorry I didn't read the question properly. I was using a cylinder when I discovered it and tried a cube without a top and bottom which both equaled 2/3.

However, an open cone is 1/2 and a cube missing its top is 5/6 so I guess there is a pattern developing here.

Cube missing 1 face (6-1)/6 = 5/6

Cube missing 2 faces (6-2)/6 = 4/6 (2/3)

Cube missing 3 faces (6-3)/6 = 3/6 (1/2)

cube missing 4 faces (6-4)/6 = 2/6 (1/3)

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