kayeselle,
That is a description of what you have done, which we already know does not work and which is not necessarily the best way to accomplish what you’re trying to do. The problem is, you haven’t yet told us what you’re trying to do, so we can only guess. I’m far from certain that using Follow Me is what you should be doing in the first place, since you mentioned “line thickness,” not tubing and not extrusions.
Please state your objective in objective terms.
-Gully
Hi Box & Gully
I’m wanting to be able to use the two opposing semicircles as a unit to explore what varieties of 3D patterns and structures I can produce by multiplying and joining them in differing numbers,orientations and intersections (as Box has started).
I am (with your promptings) staggering slowly towards achieving this. I have now produced the combination shown in Box’s illustration. Although previously I have made a dozen or so (non tube) models with Sketchup I’m finding Sketchup appears to be particularly awkward about manipulating and generating these tubular units but seems as if I’ll just have to learn more.
Ideally I’d also like to be able to change the thickness/diameter of all the components of any completed pattern/structure to view the effects of altering the proportions between object and spaces but that’s beginning to feel as if it might be trying to run before I can walk.
My only point is that if you get rid of all faces, as @Jeff pointed out a while ago, you can use the Edge Profile setting to make fat lines. This does tend to miss the point of surface modeling, but that’s neither here nor there I guess.
-Gully
Thanks Gully et al . Certainly worth me taking a look a that for changing the weights of lines … and I’m making progress in shifting the tubes/cylinders around so between the two I’ll have some stuff to juggle with for a while … before I come back to see if there’s a way to produce developments of intersecting curved surfaces but that’ll have to be another topic I expect.
I have a feeling you haven’t learnt about groups and components.
This is your model, I made one component from your geometry and deleted the rest.
Then you can move it around flip it, array it, scale it etc etc etc
Think you’re right there Box. I have now produced the first construction I wanted, but only by copy and paste of the first semicircle and then multiplying a pairing of two of them … so I better go and learn some “best practice” with components.
I’ll also experiment with Gully’s Edge Profiling idea as this may help in visualizing the effects of varying the proportions of an idea without having to re-construct it each time.
spmcgill81 has also raised an issue I should explore with his thought on “importing to layout” so seems I’m going to have to spend more time learning than making for a bit.
Thanks all
Ken
Hi Gully et al.
I’ve just been looking at the Edge Profile idea but seems the only options are to pick a pre-defined Sketchup edge … or not i.e. the thickness of line don’t seem variable unless maybe I change the scale of the drawing to make the lines look thicker 
. Am I missing something again or is that it ?
Ken
On Styles > Edit > Edge Settings, there’s a checkbox in front of “Profiles” to switch the feature on and off and a text box after it to specify a thickness in pixels.
-Gully
Ooooh … I was so close … I’ve just been dabbling with Edge Settings but missed thickness bit ( Well … in Sketchup I missed the thickness bit) . I’ll go try again.
Thanks Gully
Ken
Ha ha ! Surprisingly(not) it works just like you said 
Useful to know that. Thanks
Max thickness is 20 and the line thickness dosn’t “shrink” with the model when zooming but nevertheless helpful as far as it goes.
I’m also having some success manipulating the “follow-me” cylindrical sections (like Box’s coffee table illustration). I must just check with Box (or anyone else who knows) If it’s possible to select the whole tubular coffee table/construction and tell sketchup to make all the sections bigger ie larger diameter tubes … that would be bliss for me. Maybe I’d better look at the plugins he suggested first.
Ken
Kayeselle,
Try making a component of just the a simple arch and move/copy and rotating for a particular pattern and then using a circle of different sizes to inspect how it will effect the proportions. As a component, each arch will experience the same extrude function. By extruding the profile after manipulating the form, you will have faster feedback on the different proportions.
As far as the line thickness, for modeling purpose make the whole component a solid color ie black. When you change the circle radius, the “line weight” will look changed. See your modified example attached.
Also, I would recommend drawing the arch on a plane in line with the axes. It will make it easier to move and rotate.
Good luck.
coffee table legs2.skp (340.1 KB)
Thanks for coming back on this spmcgill81
Your example looks like it’s waiting to be turned into a Loch Ness Monster with stomach ache
More seriously you give me more ideas to pursue
Thanks again
Ken