How to find centre and orientation of object?

Rhino Rhino for Windows
1

I have the following curve:

If I select it, the gumball appears at the objects centre. How do I find the centre myself, without the gumball? None of the Osnap options seem to work for this object. The reason I ask is that I want to position this object so that its centre point lines up along a rail so that I can perform a Sweep Rail command.

Second question. The curve lies on one plane however, I noticed that the arrows of the gumball don’t lie along the same plane. Why is that and can it be changed?

Untitled2.png691×337 4.85 KB

2

Hi the_ether,

My workflow would be like this:

1: Use Orient3Pt to orient the planar curve to the Cplane.
2: Use the AreaCentroid command to find the point that you (probably) want as center
4: Use the Command OrientOnCrv pick the AreaCentroid as base point
Then inside the command check the commandline for the option to Orient Perpendicular
and next set Rotate=Yes to rotate around the curve

HTH
_Willem

3

Hi Ether- Gumball appears to find different centers depending on it’s alignment- if set to Cplane, it is is the centroid of the cplane based bounding box, otherwise the World based one- not necessarily the same of course and neither necessarily a ‘true’ center- your best bet there is AreaCentroid to mark it with a point.

To realign the gumball to the current cplane,click the white ‘bunny tail’ on the Gumball and choose Reset Gumball from the menu.

Does that do what you need?

-Pascal

4

Thanks for AreaCentroid but do you know the answer to the Gumball issue? My object is already aligned with Cplane.

Ah, just found a popup menu on the Gumball and a reset command.

5

Thanks Pascal. I just stumbled upon the Gumball’s bunny tail as you were posting your note.