Adding Boundaries to a Surface
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Use the Prospector tree to add boundaries to a surface.

When you add or remove boundaries, the surface is modified and the modification is added to the definition list for the surface.

Boundaries are defined from closed polygons which affects the visibility of the triangles inside them.


If the polygon is not closed, the boundary definition forces a closed polygon.

Areas hidden by boundaries are not included in calculations, such as total area and volume.

When creating a boundary, you set arc tessellation and specify whether the boundary uses non-destructive breaklines when adding boundaries to a surface.

Arc Tessellation

When you use polygons/polylines that contain curves for boundaries or breaklines, set the mid-ordinate distance of the chord segments, which is used to tessellate the arc segments of the boundary polygon/polyline:

Non-Destructive Breaklines

Specify whether a boundary uses non-destructive breaklines when you create it by selecting Non-destructive breaklines in the Add Boundaries dialog box.


You cannot add non-destructive breaklines to a grid surface.

When you create a boundary with non-destructive breaklines along the edges of the boundary, the triangle edges are clipped exactly where they cross the boundary:

If you create a boundary without non-destructive breaklines along the boundary edges, only triangles that are completely within or outside the boundary are affected:

Tutorial Exercise: Adding an Outer Boundary to a Surface

Tutorial Exercise: Adding a Hide Boundary to a Surface

Adding Boundaries to a Surface
Quick Reference

Toolspace Shortcut Menu

Prospector tab: Surfaces <surface-name> Definition right-click BoundariesAdd

Command Line


Dialog Box