DXF units

[neilyj666]

I've extracted a dxf (in metres) from another software package but then opening in Civil 3D, the units are Feet. I presume this is template related as my usual template is metric and has many predetermined layers which are missing in the newly opened drawing.

The question then is - when opening a dxf file, which template is being used??

[Jeff_M]

Opening a DXF file does not use a template. The DXF contains all of the data to recreate the drawing. You can open the DXF with a text editor and read all of the data it contains.. There will be an entry in the DXF for INSUNITS and it's 70 code will likely have a value of 2, for feet.

[neilyj666]

Thanks Jeff - attached is a screenshot showing the only two occurences of the string "UNITS" in the dxf - first is 2 the second is 1 - presumably this is written by the 3rd pary program that the dxf was derived from??

[Jeff_M]

Yes, this is written by whatever program created the DXF output. Those 2 units entries are for Linear and ANgular units...the 2 for LUNITS signifies that linear units are decimal format, and the 1 for AUNITS signifies that angular units are in deg/min/sec format.

I just imported an old DXF file I have, it appears that when the INSUNITS is not found in the DXF, Autocad defaults to using feet. Not sure of a way to work around that....or if you need to to, as this only would have any effect when importing drawings into this new drawing, or when it is inserted to another.

[neilyj666]

Thanks again - I'll get on to the software developers and see if they can add the INSUNITS to their dxf routines.

I generally just open these dxfs to RENAME the layers to suit my standards but when INSERTing it always displays the Units as Feet - which I don't like as I prefer all the data to be in the same units for ease of use.....

[Jeff_M]

Something you might try: Start Autocad (not C3D, so use the ".... as Autocad" shortcut) and start a new drawing using a minimal metric template. Then, instead of opening the DXF file, use the command DXFIN. This may give you results closer to what you expect.

Or, you could manually add the INSUNITS value to the DXF file. Order doesn't matter, as long as you place it near one of the other UNITS entries so it falls in the correct category. Follow the same format you see the other existing entries use.

[neilyj666]

Thanks again Jeff - both methods still gave the same results i.e. the units are feet after issuing the UNITS command - I suppose its easy enough to change this to Unitless though.....

[AllenJessup]

Have you checked the INSUNITS, INSUNITSDEFSOURCE & INSUNITSDEFTARGET Sysvars?

Allen

[neilyj666]

Yes - all set to 0.

I guess the reason is due to the way the dxf is read in C3D

[AllenJessup]

Just a guess. But I'd try setting  INSUNITSDEFSOURCE to 6.

Allen