Lines from DWG file don't import flat

I received a dwg file for a home that I’ve been commissioned to model. However, when I import the dwg file, all the lines are on slightly different planes, some are even angled. In a top view, all looks well, but in an iso view, you can see how off the lines are. Few lines are connected, making it hard to create surfaces to push/pull I can’t figure out if this is caused by a problem on my end, or the end of the architect with the dwg file itself. Anyone else have experiences with this? Thank you for your help!

Do you have access to Adobe Illustrator, perhaps try opening it in a 2D image editor and re-exporting.

A DWG file does not have to be ‘flat’ so it’s entirely possible that the plans supplied are indeed on different planes etc, depends on how the client created the file.

I expect you are just seeing the nature of the CAD file. TIG wrote a handy extension called Flatten to Plane which when used in conjunction with his Work Plane plugin will fix the imported lines. Both are available at Sketchucation.

Unfortunately many AutoCad users make this kind of errors.
Without a plugin, you can flatten the lines:

  • go to topview with Parallel Projection on
  • export to a 2D DWG file to full scale (File menu>Export>2D Image)
  • import the DWG you made back into SketchUp

You will lose the original DWG layers and circles and arcs will split into line segments, but the result is quite good enough to base your model on.


Use “FLATTEN” command in AutoCAD -

Well, you have to have AutoCad to use it. And, in my experience, it won’t flatten everything.

I’m not sure what the proper term is instead of “correctly”, but I think “the right file for sketchup” I should have written, so as not to be ambiguous.

Right, instead of using “use flatten”, I should have said: ask that architect to send you the correctly drawn file using that command.
But, it was just an idea to use.

We don’t know that it is badly drawn, do we? The OP hasn’t told us what the drawing represented. If it had been terrain, say, you might have expected lines to be inclined. @Anssi 's solution looks clever.

Eneroth Flatten to Plane was made for this exact situation. If you prefer to do it without a plugin Anssi’s method seems quite clever.

1 Like


Your litany of issues with an imported CAD file is why I abandoned the practice long ago.
Building the model upon a high-res imported Image of the CAD drawing is, in my experience, faster, easier and far less prone to propagating the errors of others.

This topic was automatically closed 91 days after the last reply. New replies are no longer allowed.