A little bit further

Sometimes, one needs to dig a little bit further to understand things that you do not know.  AutoCAD Civil 3d does have tons of settings that do a lot of different things.  After reading  the discussion group earlier this week before my service provider cut out, and watching James tweak the masking of the new 2010 offset alignment, this tip is due.

The problem lies at the feet of the old Land Desktop precision settings.  Back in LDD/SDSK/DCA days, the precision setting covered everything – labels settings to a listing of the alignment.   Subdivision parcels block strings that were off by 0.01 foot was a pain-in-my-side.

CorridorCivil 3d nicely puts away with the one-size-fits-all unit precision.   The problem can occur at the end of the alignment with the dive down to zero when the profile stops a few 0.001’ off or a 1/3 of a mm.

The tip is fairly simple.

Visit Prospector Settings Tab > Drawing Settings > Ambient Settings > Station > Precision.

Increase the value to three.


Since the value of the station Label is does not change based on this setting, increasing the station value in the Ambient Settings increases the display values in the Corridor Properties dialog box.

Now, what other ambient setting have I not adjusted…


  1. Rick Graham says:

    How timely. I was just having this conversation with the survey department wondering why their numbers were different than what C3D is putting out as far as square footage and lines with 2 decimal places set in style.

    If I have a drawing with Ambient settings for precision already, and start to parcel and then go back and change the ambient precision, does that change the one already drawn or does it only affect the one(s) drawn after the ambient settings? I’m a bit foggy on that one. Thanks for a good topic though.

  2. Your drawing objects are being drawn with much more mathematical precision than you want to consider.
    To consider your question, when you change your area precision to 4 for sq. ft. and list your parcel, instead of XX.16 sq. ft, your parcel would list as xx.1612 sq. ft. The values shown in the parcel dialog box will also show the precision to 4.

    We typically create a parcel table with the lines and area to 3 places so we can check our plats to make sure the rounding is appropriate.