Is it normal for a planar surface to have bounding box center outside of its area?

Deep questions!

Yes depending of the form of the planar surface!
Like a sort of gravity center! ;)

Oh a fringe case! Even in that case the bb center is coplanar with the surface.


What about a triangle? Like the one I attach? The bounding box is not on the same plane.

ps. I phrased the original question poorly- I meant outside of its plane. So yes you are correct Pilou, it's not that "fringe" ;)

Hi Nameless
Can you join your 3dm ?

Hi nameless, that could be a bug. Occasionally the bounding box calculation mechanism can get confused and end up tracking some portions of a trimmed surface outside of its boundary, maybe you've run into that. If you can post the file I can see if that's it.

You might try running ShrinkTrimmedSrf on it and see if it behaves better.

- Michael

I was also thinking about ShrinkTrimmedSrf :)

Hey Team and hey Michael!

Here is my file in case you want to check it out.

I will look into that command, I had totally forgotten about it!

(spoiler: ShrinkTrimmedSurface did not help)

Hi nameless, thanks for posting the file. So yes the result you're getting there is normal.

You can get a better idea of what is going on if you also use the BoundingBox command to make the bounding box itself in addition to the bounding box center.

The reason is that the bounding box is aligned with the world axis directions. On a shape like you have here that is oriented diagonally with respect to the world axis directions will have some corners of the bounding box extend out a ways from the object.

There is a center object snap available on a surface like that with a polyline boundary which will be the centroid of the points, maybe placing a point on that snap spot would work better for your case here.

- Michael

Hi Michael,

I see, thank you for shedding some light. I spam Scale with bounding box center reference a lot, so it felt weird scaling the surface and seeing it move away. But I can certainly use the center snapping point that appears when scale is activated. I was imagining the bounding box of a surface like a 2d rectangle containing it since it has no "thickness". :D