Trimming Terrains

You can select the trim operation in Trim/Split to trim a mesh using cutting elements.

Before you begin:
  • Ensure that the mesh is exempt of non-manifold problems.
  1. From the Structure section of the action bar, click Trim/Split .
  2. Select a terrain to trim.

    It can consist of several cells.

  3. Select the Cutting elements.

    Cutting elements can be:

    • Discrete polylines
    • Curves
    • Planes
    • Surfaces
    • Meshes.
    Note: The curves resulting of the projection of the cutting elements on the mesh must intersect each other or intersect free edges of the mesh. The portion of curves not taken into account at intersections must be as short as possible.
    • This case defines two areas:

    • This case defines four areas:

    • This case is not valid: The projection curve does not intersect any free edge:

    • In some cases, changing the Projection type may solve the problem.



    Those input elements are highlighted in the work area and listed in the dialog box.

  4. Select a Projection type (applied to all cutting elements).

    When scans or curves are used as cutting elements, those entities are close to the mesh but not on the mesh. To compute the trimming operation, it is required to project those scans or curves on the mesh to create projection curves.

  5. Optional: Select the Preview check box (time-consuming).
  6. Select the Trim option.
  7. Click the scissors icon in the dialog box and pick the area you want to remove in the work area.
    • Selection with the scissors:

      Result:

    • Selection with the crossed-scissors:

      Result:

  8. Alternatively, right-click the scissors and crossed-scissors and select
    • Delete: Deletes one occurrence of scissors or crossed-scissors. You could also click the icon directly.
    • Delete All: Deletes all occurrences of scissors or crossed-scissors. You could also click Remove All.
    • Invert All: Replaces all occurrences of scissors by crossed-scissors and vice-versa.
  9. Select the Result options.
  10. Click Apply.
    The area with the scissors on it has been removed.

  • The input terrain is sent to the NoShow and remains in the tree.
  • The output terrains are created in the tree and the work area:
    • If Distinct is selected, they are created separately.
    • If Grouped is selected, one multi-cell mesh is created.

If Keep Initial is not selected:

  • The input terrain is removed from the tree.
  • If Distinct is selected, the output terrains are created in the tree and the work area.
  • If Grouped is selected, the result multi-cells terrain replaces the input mesh:
    • The input terrain is removed from the work area but its name remains in the tree.
    • The result multi-cells terrain is created in the work area and under the name of the input terrain in the tree.