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Dxf files imported into Rhino are inaccurate
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10106&t=43252		 Page 1 of 1
Author:  Sheldon Dingwall [ Sat Apr 19, 2014 2:11 pm ]
Post subject:  Dxf files imported into Rhino are inaccurate
I discovered this problem yesterday on one file but I'm sure it's been causing inaccuracies in a lot of my drawings for a while.

I was updating an older file that had been imported via dxf. I confirmed the dimensions in Rhino, then printed off a copy to compare to a real part. The print out was slightly out. Long story short found that the imported objects we're slightly smaller in the Y plane. Adding dimensions in rhino displayed what the size should have been not what it actually was.

When I re drew the part then positioned it over top of the original you could see they were not the same. When I added a vertical dimension to the old drawing it read 5 mm. When I added a vertical dimension to the newly draw part it also read 5 mm although clearly the old drawing was smaller.

Any idea what's going on? I've been chasing slight errors in old drawings for years and couldn't find the source.
Author:  Kevin Waldron [ Sat Apr 19, 2014 9:51 pm ]
Post subject:  Re: Dxf files imported into Rhino are inaccurate
Sheldon,

We import all the time without problems but we used true DWG files.......... you might give this a try. ( If you note the file size for a DXF is much larger and I understand why but the smaller file size is why we like the DWG )

Blessings,

Kevin
Author:  RandK [ Sun Apr 20, 2014 9:03 am ]
Post subject:  Re: Dxf files imported into Rhino are inaccurate
So the dimensions of the geometry are correct but visually and via print they are off ? Is something not aligned to the correct plane so that it is slightly tilted with respect to world top etc ? EvaluatePt can be used with osnaps to check the endpoints of things, or the what command.

I've had issues with DXF interchange and have an old version ACAD LT, but that didn't make everything mo better. Rhino 4 seemed to do a good job with DXF but I haven't done much with that in R5. If you've got a case where the software isn't doing something right they'll definitely help figure out what's wrong. If there's something you want me to check in ACAD or Solidworks I'll be happy to. Draftsight is a free 2d acad clone available on the Solidworks site if you want another program.
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