On the triangulation dialog, there is a Use Boundary Zone(s) checkbox which allows you to pick a zone to use as a boundary. This will prevent the triangulation from crossing that boundary. How can you make a zone that will work as a boundary?
- Start by loading your source data.
- Go to Data > Create Zone > Rectangular and create a zone that encompasses the source data points (should be set to do this by default)
- Go to Data > Extract > Points from Polyline, left click on the nodes which will make up the desired boundary and hit the ESC key when you are done creating it.
- Choose to extract the data to a zone
- Go to Data > Triangulate, click “Use Boundary Zones” and choose your new zone as the boundary zone.
- Choose the source zone as usual and click Compute.
Alternatively, you could create a more precise boundary outside of Tecplot and load it.