The Auto-Flip Edges tool optimizes the Triangulated Irregular Network (TIN) edge placement by flipping triangle edges to best fit the active Elevation Terrain. This tool can be found in the TOOLS tab and only works on a selected surface.


Quick Usage Guide

  1. Select the surface and go to the TOOLS tab.
  2. Click on Auto-Flip Edges.
    1. A progress bar appears, wait for the calculations to complete.

When the Auto-Flip Edges Tool is Useful

The Auto-Flip Edge tool can be an extremely powerful tool on bare-earth projects, e.g. for an open-pit mine or for construction sites. Save time by using this automated tool to flip edges that model the actual terrain, and you very quickly get a much closer representation of the actual Elevation Terrain from your TIN.

Note! You can also manually flip the edges of the TIN by using the Flip Edge tool, which gives you more control of where you want your triangle edges.

How to Auto-Flip the Edges of Your Surface 

Create a Surface

Generate a surface from your created survey points using the Triangulate All/Within function. By default, your created surface is displayed as a TIN

Auto-Flip Edges to Better Match the Terrain

After generating your surface:

  1. Select the surface and go to the TOOLS tab.
  2. Click on Auto-Flip Edges.
    1. A progress bar appears, wait for the software to flip the relevant triangle edges.

Once completed, your surface will be optimized to better model the active Elevation Terrain.

The Advantage of Auto-Flipping Edges

The advantage of using this tool to optimize your TIN is the additional information you gain from modeling your TIN to the actual Elevation Terrain. As you can see in the images below, when comparing the original TIN (left) with the optimized triangles (right), it gives you a good visualization of the surface modeling the underlying Elevation Terrain.

As a closer examination of how the flipped edges better model to the terrain, the pictures below show how each flipped edge is auto fitted to the terrain. In this case, the edge flips to align along the breakline:

When Not to Use Auto-Flip Edges

Avoid using the Auto-Flip Edges tool over densely vegetated areas, or in situations where it is prudent to use the low-pass point grid. The idea of automatically flipping edges is optimized to calculate where lines go from the Elevation Terrain information, and surface objects such as vegetation removes meaningful information for the Auto-Flip Edges tool to make a well-informed calculation.

Tips and Tricks

  • If you only need to flip edges on smaller sections of your TIN, consider using our Flip Edge tool.
  • Read our workflow article Create a Surface for a Quarry if you would like additional information and ideas for modeling surfaces on bare earth.