Carlson 2019 vs Civil 3D

No. Export the LandXML file to you civil3D clients.?ÿ

Although I am not a proponent of propagating proprietary custom objects in a DWG file (mainly for future accessibility to that object data in years/decades to come by our heirs), you might also try (in addition to the LandXML route as suggested by @hooks) the Export Civil 3D Drawing command for some of the more common land development data types. Work will undoubtedly continue on this command to add/incorporate other data types as their export structure becomes viable. I hope this information helps.

@ladd-nelson

ok, since you brought it up...

Export C3D exports a drawing...and it is scaled to US Feet, NOT US Survey feet, regardless of what your original drawing setting is.

Native ACAD does not work in Survey Feet.

I am not sure of the implications, but someone showed that to me. I am still trying to figure out if we care.

@dmyhill

Presuming you might have meant (emphasis added for clarity):

Export C3D exports a drawing...and it is scaled to International Feet, NOT US Survey feet, regardless of what your original drawing setting is.

Native ACAD does not work in Survey Feet.

I am not sure of the implications, but someone showed that to me. I am still trying to figure out if we care.

Only you and/or your clients can determine if you can (or should) care (but I suspect you might). However, if you'd like to try some proofs-of-concept, you could explore the before-and-after results by using the Carlson Coordinate Transformation command (you can use the Screen Entities option to scale linework, etc). I hope this information helps.