Flatten AutoCAD Drawing in SketchUp – Without AutoCAD

Sometimes, when you import a DWG file from AutoCAD into SketchUp, all the lines are randomly scattered in 3D space. You expect a flat drawing, but what you get is a mess of different Z-axis elevations.

Autocad Drawing Top view

Autocad Drawing Isometric view

This article shows you how to flatten that DWG drawing directly inside SketchUp using a simple and smart trick — without needing AutoCAD at all.

Why AutoCAD Drawings Come in Messed Up?

AutoCAD files are often exported with varying Z values, especially when they come from survey data, consultants, or older 3D templates. Even if the drawing looks 2D, there might be hidden Z-depths in polylines, blocks, or text.

AutoCAD has a FLATTEN command, but:

• It doesn't always work
• It’s not available in AutoCAD LT
• It can take forever on large files

And if you don't have AutoCAD? You’re stuck.

The SketchUp Trick to Flatten the DWG

Here’s the simple trick I’ve been using for years. It forces SketchUp to give you a clean, flattened 2D version of the drawing.

1. Import the DWG File into SketchUp

Go to File > Import and select the DWG file. Make sure the import units are correct (meters, millimeters, or inches depending on the drawing) - If you don't have Sketchup installed Download a 7 Days trial from Here -

Import the drawing in Sketchup

 

2. Switch to Top View + Parallel Projection

Set your camera to top-down orthographic view:

• Camera > Standard Views > Top
• Camera > Parallel Projection

This is key: you're now looking at the drawing as if it were totally flat — regardless of its original depth.

Change camera to parallel projection

3. Export as 2D DWG

Now go to File > Export > 2D Graphic and choose DWG as the format. This generates a 2D projection of what you're seeing — meaning it flattens everything to the XY plane. 

Export your drawing as DWG

4. Re-Import the Flattened DWG into SketchUp

Finally, import the DWG you just exported. It will be perfectly flat and usable in any SketchUp modeling workflow.

Original on the left - Flattened on the right

Bonus Tips:

• Group the imported geometry to keep it clean
• Use View > Hidden Geometry to verify it's truly flat
• Explode and clean up unneeded blocks or nested geometry

 

Why This Works?

Because SketchUp's 2D export flattens based on the camera view, you're taking advantage of the 2D projection — like tracing what you see — and generating a brand new DWG with only XY data.

When to Use This Trick:

This trick is great when:

• You don’t have AutoCAD
• The AutoCAD FLATTEN command doesn’t work or takes too long
• You want to prepare 2D base plans from messy DWG surveys

Conclusion

If you've ever struggled with messy Z-axis elevations in AutoCAD files, try this SketchUp trick. It’s fast, free, and works even if you’re using SketchUp Free or a trial version.

You don't need AutoCAD — you just need to think in camera views.

Let me know if it works for you or if you have your own method!