Edit arc with Move tool

Edit arc with move tool is not changing the arc radius, as knowledge center resources suggests. On my arcs it simply moves the arc.

What’s the trick here? tried in all modes. Grabbing midpoint of arc also not working–just getting endpoints as I move along the arc line where midpoint should be.

you need to find the one of the cardinal point on the arc, i.e. ends or centre…

to do this, slowly follow an unselected arc with the ‘Move Tool’ and it will change from
unselected to selected to unselected to selected to unselected
the three unselected [but show inference] points are the ‘cardinal points’…
each will scale the arc…

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It’s worth noting that an exploded arc when welded back together alters the cardinals. You generally lose the middle one and things added to the end extend the point.

You guys are pathetically awesome. Based on your info I found out two things: 1. an arc drawn on a plane–even if a plane that has been grouped, does not like to be edited. 2. An arc drawn on a layer 0 plane, with intersecting points is then broken, and as Box says, modifies its “cardinals”. So I hid the plane on which the arc was drawn, and made sure it was not broken by other geometry and…voila, move tool does the job as advertised. How cool.

Thank you!

Kris (Sisters SketchUp Users Group Organizer & Advocate)

@krislcalvin, let’s work on this some more. This moving cardinal point thing is cool. Lots can be done - some more cardinal mastery examples. But something you wrote isn’t making sense. Namely, point 1, where you experienced difficulty moving/editing an arc on a ‘plane’ (I suppose you mean ‘face’.) And you should not have to hide anything to be able to move cardinal points.

There also may need to be some clarification about the use of Layers in SU. As in SU, Layers are only used to control visibility of stuff.

Can you attach a SKP file here with an example of an uncooperative Arc?



You’re right, I was not clear in my explanation or terminology. When I said layer 0 I should have meant what I call “loose geometry”, which to me is geometry which has not been made into a group or component. Forget the reference to layer 0, as I know that has no bearing on the issue. Intersecting geometry that is either “loose” or within the same entity breaks up the entity into new parts–which then are not as easily editable as the knowledge base suggests.

Secondly, I often create a plane or face as a “workshop” floor to aid in moving around my models–especially for zoom. When trying to grab a hold of the arc for editing, the move tool instead grabbed the workshop floor face–though I didn’t know that because this face extended beyond my screen working area.

Another big revelation was provided earlier by john who specified to use the move tool without first selecting the arc entity. I’ve never seen that condition before. Wish that had been made abundantly clear in the arc edit tool knowledge base.

Thanks for all your help!


I remember well the part about not knowing something was selected somewhere out of view. If you plan on doing this operation often, create a keyboard shortcut for Edit > Select None. I rely on Select None often enough to have assigned it to one of my mouse buttons (only 1/4" away from my thumb.)

I am building my library of shortcuts. Edit > select None looks like a winner.

Also provides great material for this upcoming local SU users group which I host.