Segmented circles causes a problem on a digital cutter



Hello everybody,
I want to buy the new version of sketchup pro 2017 to make metal parts to be cut on a CNC plasma cutting machine (works in 2D).
I noticed that sketchup draws circles, rays, rounded, curves in series of lines and not in points, can you tell me if it is possible to preconfigure sketchep so that it exports suitable traits and not series of Visible after cutting?
Because this is really embarrassing for the cutting quality of our machine.
Same for cutting text, impossible to have a result a suitable minimum, the lines of the pieces of text rounded are very marked and it seems that this adjustment is not possible in the entity window.

My question was to know before purchasing if the new sketchup pro 2017 was, when exporting in dxf, able to export a suitable file without having to modify the number of segments when designing drawings, We draw a circle or when we cornered a corner?
Or maybe do an operation that I do not know before export dxf

Thanks in advance


Someone better will come along soon but I have gone through a bit of a learning curve on this topic myself.

As you start to strike an object or (after you click the first point) then tap the tab key and type a number then lower case s

eg- TAB-> 100s {enter} That will create your circle/arc with 100 segments

Then do the remaining clicks for that object.

I was told that numbers divisible by 4 work best.

I got into minor trouble for using to many segments while going for Uber smoothness and was taught that 100 segments ought to get the job done without going overboard .

At this time you can not change the default value so you have to do that at least one per object type as I have found that if you set it to a number and draw a circle then draw another circle later it still remembers the segments until you restart the app.

So you set it once per object type per session. It is second nature to me now.


I find it better to use a number divisible by 12. That means it is divisible by 2, 3 and 4.

@ENP, what file type are you exporting?


The answer has not changed in SU 2017 from earlier versions. If you export as a 2D graphic to dxf, you will get the segmented representation of arcs and circles because that export is geared to be a WYSIWYG snapshot of the current view, which is affected by the segmented representation. If you export as a 3D model to dxf, circles and circular arcs will be exported as true arcs where possible. By “where possible” I mean that some kinds of edit operations can force SketchUp to abandon the circle info (center, radius, plane, axes) that originally defined the circle, leaving only the segmented representation.


With my friend who tries to convince me to spend a sketchup, I just try a 3D export DXF of a circle, you are right, the circle is exported correctly, and the quality of the lines is clearly superior, thanks for Information.
After several tests I find that the problem is that:

If I draw a set of 3D parts;
To be able to cut out my pieces I have to move them and place them on the same plane.
Once placed on this same plane, I must keep only one face of all the volumes extruded, therefore delete some of the volumes.
Then I notice that I am obliged to empty all surfaces so as to keep only the contour line. (If I do not empty surfaces, every time I have a “filled” surface, sketchup will fill it with lines.

This takes a lot of work and time, do you think of another solution or a plug in that could help me?
For example a plug in vacuum surface …
But I remain convinced that sketchup is a great tool, and I would like to test it in assemblies made of folded metal sheets, I also look for plug in which would save time in the field of folding on press brake.
Thanks to all


To show you, here is a test with full surface, and volume not extruded.


To show you, here is a test with empty surface, and volume not extruded.(export: 3D DXF)

You notice that the drawing does not match


It would be very simple to write a short ruby that would erase all faces in a model. perhaps one of the gurus can post one (I’m traveling without my computer for a few days or I’d do it)


Here is a test in export 2D 24 segments


Strangely, without having changed the number of segments, (24) the circle would appear correct except on the bottom right of it, or it makes big segments.


By increasing the number of segments, it will reduce the size of the segments, but they will still be (in much smaller) but will create a fault mark in the part when cutting.


I did not specify, but the window in red is my programming program of the machine: sheetcam


Export 2D TEST
For example, to create a metal sign
We find a problem of segments on the letter S


Test export 3D DXF

empty surfaces

The letter S comprising curves always has a problem of segments.

filled surfaces:

Even in export 3d, the segment problem persists


Have you read through this discussion already?


Glad someone else noticed this! I design and program parts for wooden garden furniture. Sketchup revolutionised the way I work. However straight away exporting I saw this flaw. The way I get round this is to export the selected geometry into draftsight as 2d dxf then clean the profile by redrawing the arcs properly. It can be a pain with some complex tangents for vacuum jig design but it gets the job done. I would suggest simply drawing in cad if you know what you want to achieve, it will be much quicker for machining. Sketchup is a 3D modeller after all and hopefully someone will please us machinists with a great plugin one day!


If you’re working with lettering, you might want to consider creating the text as a Windows BMP and then importing it using this plugin:

This video should explain more about using it:

The higher the resolution, the better the result. Here’s an example similar to your test:

test.skp (27.5 KB)

The image was 2925 x 1037 pixels and I used a point size of 1024.