AutoCAD Civil 3D

[#1]

I'm using the exporttoautocad command to convert a 3D drawing with a proposed surface (a TIN object) into a drawing with just contours (polylines with elevations). My original drawing is in feet and has a NAD83 state plane coordinate system.

Everything seems great in the exported dwg, except it is converting the elevation units from feet to inches!?  A contour that was originally at an elevation of 7.0 feet, ends up at 7 inches in the exported drawing. Spatial coordinates are preserved.

help please!

-d

[#2]

As a test, use the surface utilities to extract the contours to polylines before you exporttoacad.  What elevation do the polylines come in at?

[#3]

@troma, The extract objects from surface utility yields polylines with the correct elevations. (in feet)

This is my backup solution, but I really need the export to 2010 command to work because of the batch utility... (I'll eventually have many surfaces and many drawings that I need to convert...)

-d

[#4]

Oddly enough, I'm only encountering this elevation unit change issue with a surface that was a data reference. Promoted or not, the data ref'd surface ends up with contours in inches. If I open the orignal drawing that had the surface though, I can export to 2010 and voila, contours are still in feet.... Any ideas why the data reference (promoted or not) would screw up the export command?

-d

[#5]

Further experimentation suggests that it isn't the data referenced surface that is causing the problem. If I unload all the x-ref's from the drawing, then the export to autocad 2010 works as intended and the surface contours remain in feet. Any ideas?

All the x-ref's have the same drawing units/coordinate system setup and my export to autocad is set up to NOT process the x-ref's anyway...

thanks!

-d

[#6]

I'd suggest opening a Support Request with Autodesk. Even if they don't have an immediate answer, it's good to inform them of the problem.

Allen

[#7]

Did you check what units the export file is, sounds like it just may be change the units. Just a thought since 7 is still 7

[#8]

I don't think I can really help you too much, since I've never even worked in a drawing in imperial units.

But I am interested in what you mean that the contours are in inches.

Let's say your drawing units are feet, and a certain contour is at an elevation of 12 units.  You export to ACAD. What is your result?

1. A drawing where the units are inches and the contour is at an elevation of 12 units.

2. A drawing where the units are inches and the contour is at an elevation of 144 units.

3. A drawing where the units are feet and the contour is at an elevation of 1 unit.

3. A drawing where the units are feet and the contour is at an elevation of 144 units.

As for how a data refernce could affect it, I'm wondering if there is a setting in the creation of a surface by data reference, that makes it different from a surface built locally.  Go to your Toolspace>Settings>Surface>Commands and look at the settings for CreateSurface (which is the local creation command) and CreateSurfaceReference (the command for creating a surface from the data reference).  See if there is something in there that would build the surface differently.

[#9]

See attached image showing the results of the list command on the exported contour. The exported drawing is still in the correct units (feet), but the contour now has inches associated. (which is kind of weird, because normally the list command doesn't show the type of unit, it just says 'z=7.0') The other image attached shows the normal (and expected) result of the list command if I had just extract the contours manually...

I've seen other posts with a similar issue where meters became mm... I'm worried this might be a bug (though why having an xref attached would cause it is beyond me...)

-d

[#10]

Like I SAID change the units in the export drawing to Engineering there in Architectural at the moment