Elevation units turn from feet to inches when surface is made with contour lines

[Joyfer]

Hello all,

When I make a surface from a set of contour lines it has an elevation x 12 the elevation of the contour lines. I mean that the surface recognizes the elevation of the contour lines as inches and it in turn has an elevation in feet 12 x what it the contour lines have. 

Is anyone familiar with this issue? I would appreciate help so much!

Thanks and have a great day,

Joy

[tcorey]

Check in Drawing Settings and be sure the drawing is set to Feet. Check AutoCAD's Units and be sure you're on Decimal, not Engineering or Architectural. Post the drawing.

[Joyfer]

Hi thank you so much for helping out. Attached is the drawing. I have read every discussion thread and tried everyting I could think of. 

[tcorey · Accepted solution]

I looked at your drawing and the polylines have the same elevations as the surface. They are definitely odd elevations: One polyline I inspected is at 41496.00. That's above Mount Everest.

The point is, Civil 3D is working correctly and the error is likely caused during import of the polylines.

I have lowered the polylines by a factor of 12 and attached the dwg. 41496 becomes 3458. Re-create the surface and it will be correct.

Best  regards,

Tim

[Joyfer]

Thanks again,

To scale the elevation from inches to feet in the whole drawing I tried using a lisp you posted in 2012, "Polyline elev from inches to feet". It asks for defalt elevation so I enter 0,0 and for the second point I put 1', which doesn't seem to work. would you mind explaining how that works? Attached is the lisp I am talking about.

[tcorey]

I don't know what you might be doing wrong, but that routine doesn't prompt for any user input. It simply selects all lwpolylines and divides the elevation values by 12. There are no prompts in the routine.

Be sure you have no polylines on thawed layers if you don't want those polylines modified.

Use Appload to load the routine. Nothing else to do, it just runs.

If you can't get it to work, feel free to phone me at my office number, 530.221.2994, tomorrow, and I will help you through it.

Best regards,

Tim

[Joyfer]

Great, I was trying to run the lisp in the command line after I loaded it but I see that it works after just loading it. You have been so helpful I can't thank you enough! I'm glad the solutuion was easy, I work alone from home and sometimes I think I'm loosing my mind 😕