Offset tool Improvements

The offset tool says “you must select a single face or two or more simply connected coplanar edges.”
Actually the selected edges must also be not colinear.
Also, a single edge should be allowed if it part of a single face or part of only two coplanar faces.
Multple faces and/or multiple unconnected edges should be allowed if they are all coplanar.

Finally ARCs should ALWAYS result in offset ARCs not CURVES, This is a nasty limitation because CURVES do not have centers and can’t be dimensioned as ARCs.

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I agree. For the moment you could try some offset plugins. Maybe they do more what you need (have not tested them recently):
[Plugin] TIG-Smart_offset • sketchUcation • 1 by TIG
Extension | SketchUp Extension Warehouse ($)

I tried Truoffset a while ago. It converts arcs to line segments which is a step worse than the SketchUp offset…
The Sketchucation SmartOffset works only on a single face and arcs become curves.

Why would you want to offset a single edge? That is the same as copying it.

The result might be the same but the process of doing it is not.
Say have a single triangular face at an arbitrary angle and want to copy one edge a certain distance outside the face.
An offset tool knows to maintain the new edge on plane with the face and to have its end points offset at right angles to the end points of the original edge.
The Move/copy tool requires you to hold control and rely on some form of inferencing from other entities that may not exist. Not easy.

I had a new user ask me why his offset from a single edge of a face wouldn’t work. His common sense told him it should work.
And I agreed.

The example you mention is easy with the existing triangular face.
The inference popup is ‘Perpendicular to Edge’ (or outside face > ‘Constrained on Line’) but only shows after getting the inference popup ‘On Edge’.

‘Constrained on Line’ while holding down [Shift] only after getting 'Perpendicular to Edge].


  • pre-select the edge and move it, grabbing it at some location on the edge or
    grab edge with the ‘Move’ tool at some location on the edge
  • hit [Ctrl] to get the +sign so to now move a copy of the edge
  • move the copy towards its original (superimposed) till you see ‘On Edge’ and now hover on face till you see ‘Perpendicular to Edge’
  • If needed outside face area, hold [Shift], to continue perpendicular + on same plane, getting popup ‘Constrained on Line’.
  • After moving arbitrary distance, type the offset value and [Enter]

It’s beyond my comprehension that either of you would call all of that easy for an new user.
Compare to what an improved offset command would do where all of the above is automatic.
That’s what I call easy.

Think of it as a 2D version of push/pull.

Conversely imagine Push/Pull if required all that inferencing to maintain the direction perpendicular to the chosen face.
The fact hat it doesn’t require all that is why people love it.

I just don’t understand how offset an edge or a series of co-linear edges in 3d space would work. There is no defined plane. It could go in any direction.

As I said in my original post:
Also, a single edge should be allowed if it part of a single face or part of only two coplanar faces."

Agree with this, definitely a surprise.
Strange that offsetting a circle results in a circle but not for an arc.

One would use the edge and some point in space (not on line of edge) to define the plane. Next click is the direction of offset. Then the value input. Sdmitch already made such a plugin, if I remember well.

@barry_milliken_droid, i agree that the inference sequence isn’t that simple to a new user. Once one sees how SketchUp uses inferencing (we all need to learn that anyway) and memorises the last focused entity, then it’s not that difficult anymore.
I just wanted to point out that an edge bounding a face has its “simple” offset with the ‘Move’ tool. Endpoint move at 90 degrees in plane.

As for offsetting arcs, the tool should have two options:

  • to result in a curve (as it is now) and
  • to result in an arc, maintaining the arc properties. That would be “fair”

Imagine the complaints when one needs to cut off both end segments of the offsetted arc instead of getting the curve with amputated end segments straight away. So there should be both options to choose from.

For a single edge, I sometimes use Thomthoms EdgeTools (split faces…):


true, but there’s the advantage that a double click will copy it the same distance as the last offset, if that’s desirable, and it would be guaranteed to be copied perpendicular to the original line, which would be easier if the line is non-orthogonal to the working axis.

agree big time