About flattening and cleaning AutoCAD drawings before IMPORT TO SKETCHUP
http://sketchucation.com/forums/viewtopic.php?f=15&t=43809
excerpts below
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Some Top Tips for importing dwg / dxf into SketchUp.
If you have Autocad........
1. If you are importing a 2d CAD file, run the FLATTEN command - this ENSURES everything is actually 2d.
2. Run OVERKILL command - gets rid of any duplicate data
(These 2 Commands are possibly Express Tool Commands).
3. Run PURGE command (most important Tip of the lot). Run PURGE again just to make sure !!! (PURGE ALL)
If you don't have Autocad, get the person who is sending you the file to do these 3 things.
..........
Hope this Helps
Bye
Howard Leslie
In AutoCAD, copy what you want to import to SketchUp to a new file. This avoids many import issues it seems - seems like old DWG files can contain so much stale data that you get more junk in SketchUp.
- Place everything around Origin
- Zoom extent - to ensure there is no stray objects far off
- Flip to a side view and check if some lines go up/down in an extreme distance. (I often come across drawings where lines shoot 50km into the air )
- Explode Polylines and 2dPolylines (If a polyline contains Arcs SketchUp will import them as straight lines from start to end)
- If drawing should be 2D, flatten to ensure it is.
- Purge All
I find even drawing over can cause problems, as you can still inherit some tiny fraction of inaccuracy - like slightly off angle that just mess up everything later on. If anything, I try to draw with the rectangle tool as much as possible to ensure proper 90 degrees angles.
I often turn on Edges Color by Axis after importing to spot lines that are off axis.
Thomas Thomassen — SketchUp Monkey & Coding addict
Importing AutoCad ACA Walls etc into Sketchup: coming soon