Skip to main content
Solved

Calculate Volumes from Unclosed Meshes (.dgn)

  • May 12, 2026
  • 2 replies
  • 65 views
galigis
Enthusiast
Forum|alt.badge.img+22

Hi All,

I’m trying to calculate volumes on meshes in a dgn file. The dgn file represents rail embankment / earthworks (ballast, formation, etc.). Below a screengrab of the design:

My current workaround is DGN Reader → SurfaceBuilder → SolidBuilder → VolumeCalculator but am finding that some of the meshes are not closed. Before calculating any volume I need to close the meshes but can’t work it out,

Any idea about how close the unclose meshes?
 

Thanks!

Best answer by daveatsafe

Two possible solutions:

  1. Use Hub transformer TINVolumeCalculator to calculate volumes of both the top surfaces and the bottom surfaces to a common base elevation, then subtract the bottom value from the top value to get the total volume. (DWG_Calculate_Volumens_safe.fmw)
  2. Extrude the top surfaces and the bottom surfaces down, then clip the bottom solid from the top to get the resultant, and measure its volume. (DWG_Calculate_Volumens_safe2.fmw)

Please the attached workspaces.

    2 replies

    dmitribagh
    Safer
    Forum|alt.badge.img+19
    • dmitribaghSafer
    • Safer
    • May 13, 2026

    Hi ​@galigis,

    Here is an idea, but it’s not a perfect or universal solution. If your meshes have flat bottom surface, you can extrude them down by a number exceeding your real values. Then, you also extrude the bottom part only (or its footprint or convex hull, or maybe even a buffer) - also down and even more. Before extruding, make sure you coerce both objects to surfaces. Then your second extrusion becomes a clipper for your first extrusion. The output form the outside port is the solid you are looking for. The screenshot here show a mesh with just a single surface, it is not closed at all (red), but after the process I described I get a properly closed solid (green), and I can calculate its volume.

    Dmitri

     

      daveatsafe
      Safer
      Forum|alt.badge.img+23
      • daveatsafeSafer
      • Safer
      • Best Answer
      • May 21, 2026

      Two possible solutions:

      1. Use Hub transformer TINVolumeCalculator to calculate volumes of both the top surfaces and the bottom surfaces to a common base elevation, then subtract the bottom value from the top value to get the total volume. (DWG_Calculate_Volumens_safe.fmw)
      2. Extrude the top surfaces and the bottom surfaces down, then clip the bottom solid from the top to get the resultant, and measure its volume. (DWG_Calculate_Volumens_safe2.fmw)

      Please the attached workspaces.

        Community Stats

        32,617
        Posts
        123,788
        Replies
        40,963
        Members
        Terms & ConditionsAccessibility statement
        A product of
        Safe Software respectfully acknowledges that we live, learn and work on the traditional and unceded territories of the Kwantlen, Katzie, and Semiahmoo First Nations.