Surface Edits that don’t Stick: Snapshot dilemma

If you need to experiment with some options while editing Civil 3D Surfaces, the  “Snapshot” function could help.  Below is what Civil 3D Help File has to say:

A snapshot is a surface operation that captures the current state of surface.

In Toolspace, on the Prospector tab, expand the Surfaces collection, right-click the surface, and click Create Snapshot.

The current surface points and triangles resultant from previous surface operations are contained in a surface snapshot operation.  When a surface is built, previous surface operations are ignored and the surface build begins at the snapshot operation. Surface operations that are included in the snapshot are marked with  [camera icon]  in the Prospector tree.

Snapshots can also be created automatically.  A LandXML setting enables you to specify that a surface snapshot be created in the surface definition subsequent to the importing of a surface when using Import LandXML. 

It is a safeguard, allowing surfaces to hold their built state, regardless of what happens to the items in the history before that point.  Perhaps best used when pasting surfaces, see example below

Original Surfaces

  1. The EG surface is pasted into the FG surface
  2. No Edits

Boundary Edit - No Snapshot

  1.  The EG surface is pasted into the FG surface
  2. A boundary is then added to the EG surface
  3. No change is seen in FG surface.

Boundary Edit- With Snapshot

  1. The EG surface is pasted into the FG surface
  2. A Snapshot is created in the FG surface
  3. A boundary is then added to the EG surface
  4. No change is seen in FG surface.