Drawing a single line all the way around curved surface


I created a curved ring and want to draw a line horizontally all the way around the ring so that I can easily add detail with “tools on surface”

The tools on surface “line construction drawing tool” does allow me to do exactly this except as I rotate my view (spin the ring or camera) I am forced to make short end points and start another line. I thought I could simply keep doing this and then just select all the lines together with shift key…

Except after I place about 3 or 4 lines, they all disappear because I guess this tool only allows a certain number of lines.

Is there a way to kind of do a “follow me” tool thing to make the line automatically go around the ring?
Or after creating 2 or 3 segments around the ring, if I group them would they stay there instead of disappearing?

In my picture, you can see I am able to make 2 or 3 line segments and can but if I keep making more as I go around the ring, they disappear before I get to the end of the ring.



I found your quote on the same question that you kindly shared as such"

If you have two colinear edges butted end-to-end, draw a third edge from the common endpoint to anywhere, then erase it. The original two edges will now be one, with the extra endpoint gone.


I tried this and it didn’t work, at least with tools on surface which is how I’m drawing the line. After I created the third line from the common shared end point of the previous 2 lines and then deleted the new line, the first two lines are still 2 different lines. So If I try to keep going around the ring, they too will disappear.


I have two colinears.


Good one! You are Colin, and you have two ears? Or am I crazy to see a joke there.

I figured it out.

I didn’t realize that in the other post, there were two different plugins. One plugin correctly answered the question “Weld” is a different plugin from “fredo6” with the remove lonely vertices.

Thank you everyone, love the forum.


One of the easiest ways of getting the line you want is to add in another of Fredo’s plugins, Curvizard.
Here you see I only need to select one segment and it will weld the whole ring.
Also you are working inside out which will cause you problems when 3d printing. White faces are the front and greyblue are the back faces, so your ring should show all white.


awesome ! box. Thank you so much.

About the wrong color. Where or when does one choose a color for the model?

I figured you render things later, never knew color would matter during construction. Thanks for the heads up.

oh I see. In video you picked reverse faces to make it white.



Face orientation is important right from the start.
Reversed faces can cause all sorts of problems with Rendering and Printing. Some render engines don’t see textures on back faces, so your model may look brilliant in SU but once rendered may have no colours/textures or simply have holes all over it.
3D printing basically requires solids, one reversed face can stop something being solid. Plus the back faces tell it what is the inside of an object. So theoretically, not that it would, your ring as it was would print as a void rather than a solid.
Many people change the back face style to a garish colour so they can spot them easily and correct them as they go. There is nothing worse than trying to pick through a complex model looking for tiny reversed faces.


Two more ways:

  • without plugin
  • SketchUV plugin


another alternative is to create a surface that intersects the ring and “intersect faces”. This way it doesn’t have to be on one of the construction lines and could follow any shape.


Wow, I’m blown away by all of your ideas folks and by your generosity of sharing the info!
Many many thanks.

About “Intersect faces”. Is this a native tool or a plugin?


It is a native function.


Thanks, yes I see it when I right click on the mouse. Thanks.

So basically, by free drawing a plane, and then “follow me tool” I can make anything and then intersect faces with the ring like in the photo.

Great idea and I will try this too!


Hi @Rick,

In your short time here as a member of this Forum, you have put forth several very interesting questions that have elicited a number of incredible responses. I am suggesting that one of the SketchUp Team Members (perhaps @AlexB or @jody) repackage your current posts into a special thread directed to new users as an alternate means of quickly exposing them to certain features that may not be widely known to all of us.

You are definitely a welcome addition to this community, IMO!


Thank you, Good sir (I hope that’s right)

I ask a lot interesting questions because I’m wired like that and often learn new things from the inside out, or backwards. I am watching videos every night to learn the native tools but it’s hard to learn how to actually implement them. For example, I’m having a very hard time trying to figure how how to flip a circle or any other 2d plane from the horizontal axis to the vertical axis. But I mean flipping it so it pivots from the center.

Anyways, to show how strangely I learn things, (doing the hard stuff first), I built my own motorcycle from the frame up without ever having owned or ridden a motorcycle before. Working with metal led me to casting and fabricating jewelry as a hobby, and now I’m interested in learning how to 3d model jewelry. (Since it would take years to master hand carving wax).

Thanks for the comments and hope I can be helpful too one day.


The rotate tool will snap to the center, then click and drag to get the orientation you want, click to set that, then click and rotate.


ah I see. I watched videos and realized the color change to indicate axis. Thanks again.