Objects shift when Copied and Pasted between two drawing files

[cadtag]

This is an oddity -- and i'm bemused by what's happening,

Drawing A is an existing site plan (surveyor on 2016), drawing B is the demo sheet and has A xref'ed in. In model space of the demo sheet, I tagged 140 trees to be removed with block markers.
Then, copied all of those block using COPYBASE and a coordinate of 0,0,0. But, pasting that into A so I can locate the base file trees and change them to a demo layer, and the block symbol lands off the tree node. DIST tells me "Distance = 4.2296383, Angle in XY Plane = 15d29'8"

Both drawings are on the same coordinate system, both are in WCS, INSBASE is 0,0,0

If I XREF B into A, then the symbols land correctly visually, but.... the original point node in A and the referenced point node in B list out as different coordinate, off the same distance as the pasted symbol.

[MMccall]

Any chance the xref of A in B is not at 0,0,0?

[cadtag]

Nope -- all at 0,0,0. All on WCS, all INSBASE of 0,0,0

Turns out, the 2016 xref into 2017 is the problem. There's a new INSUNIT setting for 2017 -- 21, which is US survey Ft. about 4 feet per million -- no biggie unless you work in real world state plane coordinates. In which case you can be totally hosed.

[MMccall]

Ugh, I hate being hosed ...


Is the solution then to save drawing A with 2017 before you xref it into 2017 drawing B?

[cadtag]

well, my solution is going to pretty much be what it always has been -- set INSUNIT to 0 and consider it a poor idea and worse implementation,

Not to much need to import drawings in parsecs, or nanometers, but someone in adesk thought it was vitally important to include those as INSUNITS values.

I actually had opened and saved the base (survey) file in 2017, but naturally it used FEET, since Survey Ft did not exist as a unit in 2016. Guess I need to detach everything in the project, set INSUNITS=0 in my sheet and model files, and then reattach everything

[Tom Beauford]

Is BASE set to 0.0000,0.0000,0.0000 in both drawings?

[cadtag]

Hi Tom,

Yes - base is 0,0,0. INSUNITS in the sheet were the new setting of 21, US Survey Ft, so the survey file created in c3d 2016 with units of "feet" was being scaled as it was referenced.

with FL-N state plane coordinates, and 0,0,0 out in the gulf of mexico, that was giving me a positional error large enough to matter. Since this job is in Leon County - you'll likely experience the same thing if your drawing's INSUNITs is set to 21, and 2016 or earlier files with INSUNTS=2 get referenced in.

Best fix i can think of for my work is setting INSUNITS to 0 in all my working drawings.