Export skp to dxf for autoCAD

I am not able to export my skp files successfully for use in laser as a dxf. I can export the file - tried it both as 2D and 3D. But, my laser cut guy tells me all the circles and radius’s are still made up of individual lines and cannot be cut this way. I also tried selecting each radius and circle and then “weld edges” but this didn’t help either. I have a 30 day free pro trial and if I can’t export successfully to dxf for laser cutting then I don’t need the pro version. Each time I’ve created the dxf’s I get an ok audit at the end.

If your circles and arcs in SU haven’t been modified from the original ones, a 3D export should show in AutoCad as true circles and arcs.

But if you have used FollowMe or exploded any of them they will revert to edges. Weld only joins the edges into a SU Curve, it won’t re-make an arc or circle, though there are extensions that can do that - NI Lines to Arc for example.

Upload an example SU file (.skp) so someone can have a look and help you better.

hi John. Thanks for the reply. I’ve never done this so need to ask how to upload a SU file for you to see? Please advise. tks

If it is smaller than about 15MB, either drag and drop it from File Explorer into your next post, or use the Upload button (the 8th icon above where you type your text), and select the file to upload.

If it is larger, use a file serving service like Dropbox, OneDrive, or WeTransfer and post a link to the file here. Make sure it is shared, not private.

Here is SU file I need to have laser cut. File called “pull bar”. It includes two versions of the part…one with “fills” removed and the other fills left in. There must be some setting I don’t know about in SU…or a way to successfully save in dxf form so my laser cut guy can cut without having to make changes or redo the entire part in CAD.
Pull Bar.skp (307.1 KB)

I was able to export successfully to dxf, but I did make a few changes first. I rotated the piece 90 degrees and placed it on the X,Y plane. Then changed to Top View and changed Camera from Perspective to Parallel Projection. then Export - 3D Model - AutoCAD DXF File.
Pull Bar.dxf (1.2 MB)
I suggest that you explore and learn SketchUp through all the available tutorials on line, SketchUp Campus, The SketchUp Essentials Homepage, Home - MasterSketchUp.com, and a myriad of others.

hmm. ok. Can you send me back the SU file you created so I can study the changes you made?

Also. Each of my attempts to export to dxf came back successful as far as SU is concerned. But my circles and arc all have the broken lines (or sides) to them - which won’t work in CAD to laser cut. Of the changes you made I assume the only one that would make the dxf work for laser cutting is the fact you changed camera view to parallel from perspective? Otherwise your changes don’t seem like they would make my circles and arcs be one line instead of a bunch of lines? Please advise.

When exporting a 3D model the camera view is absolutely irrelevant to the export result, except, perhaps, affecting what is visible on your screen when yoou open the file in CAD.

The guy who laser cuts my parts says when all of the attempts I’ve made sending him dxf’s exported from SU they initially look ok but when he closely inspects the circles and arcs the individual lines will be a problem when cutting. The laser machine will try to cut a whole bunch of individual lines instead of one continuous line…even for a circle. So I’m looking for help for changes I need to make in SU to give him circles and arcs that are one continuous line and not broken up. SU pro is supposed to be able to export dxf’s successfully…and each time I do it I get a good audit report…but they don’t work at his end. earlier today I uploaded a sample of my SU file. Can anyone tell me what changes to make so dxf’s work for laser cutting?

Your problem is that your model has no arcs or circles, only curves. Curves always become segmented lines when exported. You have to use the circle and arc tools to get circles and arcs, and forget about welding the result to curves.

I have never tried to weld sides of a circle or arc together until now that I’m tryin g to get a usable dxf for laser cutting. Tried it just hoping it would help but didn’t. You say I need to use circle and arc tools…that is what I’m using. But even when using either the circle or arc tool they still use sides, right? Or, is there a different tool I should use, or adjustment, to make circles and arcs one continuous line. Or, now I’m wondering if the laser cut machine will cut these broken lines just fine and I don’t have to change anything that I’m doing? ugh. Sure wish I could talk to someone that is actually using SU to send successful dxf files to get laser cut. Anyone doing this?

The file you posted had its lines, arcs and circles welded into curves so they had lost their “consciousness”. You know if an entity is an arc or circle by selecting it and looking at Entity Info,
To export them as arcs and circles to DWG/DXF you have to use the 3D Model option to export.

It is possible. You might try, when drawing, to increase the segment count to make the lines as short as practicable, but I understand that this method takes longer to cut than when the machine can use preprogrammed shapes.

So, maybe it’s possible that the laser machine will actually cut my circles and arcs but not as quickly as if the dxf was originally generated in ACAD? For years I have used SU to dimension all my parts, then I send pdf’s of screen shots to the laser cut guys and they would re-create all my parts in ACAD because I couldn’t give them a dxf. Now that I can give a dxf from SU…but they might cut slower…then might I assume the volume cutting of parts for me will cost me more in the future using my dxfs from SU than if I just had them continue re-creating the dxf’s at their end in ACAD (because their dxf’s would cut quicker)? Note 1. I do usually try to keep as many sides to an arc or circle as what SU will allow for the most part. Note 2: I have never welded a circle or arc together until now just to see if it made a difference and it didn’t seem to. That’s why I uploaded a file with circles and arcs welded…had seen that in a different post and wondered if it would help.

The problem is that the fact that a series of segments are meant to represent a circle or circular arc is carried in metadata attached to the curve. Export to 3D dwg/dxf as a true circle or circular arc depends on this metadata. Various kinds of editing force SketchUp to discard the metadata. Welding segments into a curve does not generate or restore this metadata, it just causes the collection of segments to be treated as a single object.

You can cause SketchUp to recreate the metadata by redrawing a circle or arc using one of the native tools. Of course, that implies that you know the center, plane and radius, which are among the lost metadata. There are extensions available that analyze the segments to determine if they look like a circle, calculate the center and radius, and redraw automatically , e.g. recurve. There are some limitations on their abilities, though. Depending on how a circle has been edited, the analysis may fail.

Here it is renamed:
Pull Bar-1A.skp (279.7 KB)

When I imported the DXF into my CAD/CAM program(ASPIRE) the circles and arcs are circles and arcs, not line segments. Even though this is a 2D drawing if you need to export as 3D Model - AutoCAD DXF File

Or you could use a plugin to recreate the metadata without redrawing. I did that in the attached .skp file.
Pull Bar.skp (35.9 KB)

what plugin did you use?

Exploded Arc Lines to Arc

Freodo’s Curvizard works too.

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