Export to DXF- holes too notchy

When I send dxf files to my fabricator to load into his plasma cutter, he complains that the holes are too notchy. I am doing a 1" dia hole with 90 segments (max I can get SU to do) and he still complains. Any way to make a hole more round and less a multigon? This is a simple hole, drawn correctly on one surface and then extruded through. The completed model passes the inspector2 check for solids. The dxf file saya it is OK.

Use Camera Top view (or the relevant one to your drawing), parallel projection, and export as 3d model to .dxf and you will have true curves.

BOX- Thanks. I am doing exactly as you suggest, with the exception of saving it as a 2d dxf. My fabricator says he needs a 2d file and can’t work with a 3d file.

The point is if you export as 3d .dxf it will open in other programs as a 2d with true curves.

AHHHH! now I understand. Let me see how that works.

For reference, this is a common misunderstanding about the exporters in SketchUp. The 2D exporters are meant to create a file that is effectively a screenshot of the currently active view. This makes sense, as they are generating a 2D representation of a 3D model. As such, they don’t make any interpretations, they export verbatim. For example, because a circle is represented on the view as a series of edges, they export it either as a raster image of that series or as a series of line segments if vector format.

The 3D exporters, on the other hand, try to do the best job they can with the model as a whole. The dwg and dxf exporters, in particular, notice when a sequence of edges has associated circle metadata and export a true circle or arc.

In the AutoCad world, there is no separate file type for a “2d” drawing, the DWG/DXF format is always fully 3D and every point is recorded with all three coordinates.

If I would need a 2D cutting “stencil” I would not bother with modelling the thickness of the object. AFAIK it only confuses the CNC machine. I would draw the “stencil” on the red-green plane, and export the model as a 3D file with only the edges, unchecking all the other features.


Thank you all very much for your inputs. I have tried several of these techniques and sent them to my fabricator. I’ll see how they look to him. I’m intrigued with the concept of a no thickness part, as that does indeed seem to be confusing the plasma cutter. I’ll try a flat with holes in it and no thickness and see how that goes over.