Noob - joining lines that surround an area



I draw a lot of short lines to surround a complex area, then I want to pull it up into a solid, but find that I can’t select it. I think this may be because some of the lines were drawn in the wrong direction - by which I mean that most of the lines were drawn so that from the beginning to the end of a short line, it went in a clockwise direction around the area, but not all did - some were the other way around. Is it possible to get SU to recognise the area without having to redraw it correctly?

Another example is this : I draw a circle, then attach to it the cross-section of a V-pulley. I select the circle, click the Follow-me tool and double-click the cross-section to make a 3d pulley - and it works fine, but I then find that I can’t select the circle, because it has turned into the sides of a many-sided polygon. Can I recombine them into a circle so that I can select the plane subtended by the circle, and extrude it?


The order in which you draw edges does not matter. If a face doesn’t form there are two possibilities. Either the edges are not coplanar or you have left a gap somewhere. Both of these can be avoided by paying closer attention to SketchUp’s inference engine snaps.

When you follow-me or push-pull extrude a circle or a shape that has a circular arc as part of the boundary, it’s identity as coming from a circle is lost and can’t be restored.


As has been said…
Pay close attention to the Inference tool tips.
Hover the tool cursor momentarily and click only when you see the Endpoint inference.

SketchUp will create a Face provided the Edges that bound it meet the following conditions:
• The Edges form a closed loop.
• All the Edges are coplanar.
• No stray Edges, coplanar with the closed loop, project inside the loop.
• The Edges are not too short, say, <.002 in length.

Tracing over the segmented geometry with the Circle tool will typically result in an Arc or Curve polyline entity.
Weld the segments together using a weld plugin.
[TIG-weld v2.0] ( — SketchUcation PluginStore


Thanks very much, Folks, for the explanation of what I’m doing wrong when joining lines. They looked joined, but the computer has much better eyesight than I have. I’ll be more careful.

On my second point - when making a V-pulley, the circle that surrounds the hole becomes a polygon. After a bit of fiddling around, I succeeded in getting my pulley onto its shaft, but I’m not 100% clear on how I did it. The real reason why I wanted to select the circle that runs around one end of the hole, was to find its centre, so I could align it with the centre of the shaft. If the circle can’t be used, is there a way of finding the centre - or a different way of getting the new component (pulley) onto the motor shaft?


If you are on a recent version of SketchUp, hover the cursor over a vertex of the circle and the inference engine will provide a snap point at the center:


Center of sheave bore and center of shaft are common points.
Endpoints that define the bore and shaft are also common points.
Try turning on Hidden Geometry and align bore to shaft referencing the endpoints.
look to the top menus and click … View > Hidden Geometry


I’m most grateful for the time and effort you have put into answering a beginner’s queries.
My problem is resolved, and I’m making great progress with my design drawing.