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CAD Forums => CAD General => The Third Dimension => Topic started by: DPATTERSON on July 07, 2014, 10:28:55 AM

Title: Civil3D Subtracting Elevation from all points?
Post by: DPATTERSON on July 07, 2014, 10:28:55 AM
Hello Everyone,

Just wondering if there is a way to have a point group and subtract a uniform elevation from all of them.  I have an E/G surface and i want to lower it by .15m!


Thank You In Advance,


-David
Title: Re: Civil3D Subtracting Elevation from all points?
Post by: Mark on July 07, 2014, 10:41:51 AM
not exactly what you asked for but ...

Quote
Changing the Elevation of a Surface
 
 
 
Change the surface elevations by adding or subtracting an amount from the existing elevation of all the surface points, which raises or lowers the surface.

Note
TIN or grid volume surfaces do not support editing operations.
A positive value increases the elevation; a negative value lowers the elevation.
To raise or lower the surface
In Toolspace, on the Prospector tab, expand the surface Definition collection, right-click , and click Raise/Lower Surface.
The following prompt is displayed:
Amount to add to all elevations:
Enter a positive value to raise the surface or a negative value to lower the surface.
The surface is adjusted to the new elevation.
The operation is added as a Raise/Lower operation to the Edits list view in the Prospector tree.
Note
The Description column in the Prospector list view displays the value by which the surface was raised or lowered.
Title: Re: Civil3D Subtracting Elevation from all points?
Post by: Jeff_M on July 07, 2014, 12:02:45 PM
In the Propsector select the PointGroup to edit, right click & choose Select. All points in the PG will be selected, right-click in the drawing canvas, select Datum, enter the amount to move up/down.
Title: Re: Civil3D Subtracting Elevation from all points?
Post by: DPATTERSON on July 07, 2014, 12:07:28 PM
Thank you So much!
Title: Re: Civil3D Subtracting Elevation from all points?
Post by: mjfarrell on July 07, 2014, 03:31:52 PM
I wouldn't do it that way....
either way

only IF you are adjusting for an incorrect starting datum, i.e. Bad Bench Mark

Otherwise, I would either A and or B

Export points and reimport, add to new surface and lower as described.

Then you can get the volume when that 0.15 is removed.

I suspect this is for a volume computation and not for a datum adjustment.

If it isn't a volume issue - it might be best to edit the original point database instead.