It might not seem obvious, but it is very important clean up
DWG files before importing or linking into AutoCAD. Revit is not AutoCAD and it
is important to note that Revit will not behave like AutoCAD. So we need to
take this into account when working with DWG files. Spending a few minutes
cleaning up a DWG file before importing or linking that file can prevent real
problems from occurring down the road.
Here are some items to consider when working with DWG files
in AutoCAD.
1.
Be aware how far the CAD geometry is from 0,0,0.
Different versions of Revit get squirrelly if the geometry is either greater
than 2 miles or 20 miles from 0,0,0 in AutoCAD. While you are checking this,
look for scratch or unnecessary geometry that might just be hanging out
somewhere. If you don’t need it, get rid of it. Use Zoom extents in AutoCAD to
see the extents of the geometry.
2.
Review the layers in AutoCAD. Make sure you are
aware of what is on/off or frozen / thawed. If there is geometry on layers that
are hidden or frozen, consider deleting that geometry and purging the layers.
Put the DWG file on as much of a diet as you can.
3.
Be aware of blocks that are using in the DWG. If
you are experiencing display issues in Revit, the issue might be with the
block. It’s only been a problem for me a couple of times and exploding the
blocks in AutoCAD corrected the issue. The simpler the CAD file, meaning few
blocks, xrefs, etc that are in the DWG file, the better.
4.
Put the DWG on a Diet. Purge ANY and ALL unused
layers, blocks, styles, etc from the DWG. The less Revit has to track the
better.
5.
Verify your units of the DWG file before
importing.
6.
Watch out for really small geometry. Revit will
generate a warnings for lines that are smaller 1/32” or 0.75mm.
7.
Consider linking or importing DWG files onto a
separate workset.
8.
If you only need to see a DWG in a single view,
always use the Link to Current View Only option.
9.
I think this goes without saying, but worth
repeating. To everything possible to avoid exploding imported DWG files.
