Keep Inside is a surface item modification tool that keeps a specific area within a surface and removes TIN segments that are outside of a selected boundary. 

The Keep Inside button appears in the TOOLS tab and only works if both a surface and boundary are selected. 

Quick Usage Guide

  1. Select the surface and the boundary (hold Ctrl on your keyboard when clicking the items).
  2. Go to the SELECTION TOOLS tab.
  3. Click Keep Inside.
  4. The triangles outside the boundary are removed from the surface. 
    1. The triangles crossed by the boundary are cut out to fit inside the boundary.

Where to Use the Keep Inside Tool

  • Use Keep Inside to create a smaller surface that focuses on your area of interest.

Tips and Tricks

  • The elevation of the kept surface area remains the same as the original surface. 
    • The elevations of the boundary vertices are not included in the kept surface item.
  • Using Keep Inside completely deletes the external part of the surface from your project.
  • It is possible to keep multiple smaller sections within a surface simultaneously by selecting the surface along with multiple boundary areas within.