Is there a way to select the diameter of a circle/cylinder?

Rhino
1

I want to rescale a cylindrical shape, but am struggling to select its actual diameter to do the scaling.

Selecting “end” is getting me some slight diagonals and producing an incorrect size.

Thanks.

2

Hi John,

One way would be:

Set CPlane to Object
Subselect one end of the cylinder as the object to set the cplane to.

Use Scale2D with the origin set to the centre of the cylinder end face (use the Centre OSnap). Set the first reference point to a quad on the perimeter. Type the desired radius in on the command line for the second reference point and hit return.

Undo CPlane change to get back to normal grid orientation.

HTH
Jeremy

3

Hi @John_Swiers

Though Jeremy’s method is the way I would do it, you can also use “box edit” command or panel.

Oddly and I think it’s missing from box edit (though I don’t use it often) is a way to scale a cylinder by diameter, the editing choices include scale but only by percentages. One would think that for cylinders McNeel would have had the smarts to add a diameter or radius option.
RM

4

Or even better: Have the ModifyRadius command work on cylinders. If you make your cylinders by extruding a circle (with history on), that another way to go (by using the ModifyRadius command on the original circle). I use that a lot for hole patterns (speaker, lamps etc).
-Jakob

5

Hi Jakob -

I’ve added that to RH-41104 ModifyRadius should work on Spheres
-wim

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