Extending a 3D TIN beyond the points used to create it

[LostCarto]

Hello,

I am attempting to create a 3D plane from three points. However, I would like to have this plane extend outwards beyond the extent of the three points, potentially to a bounding polygon. The elevation of the plane would maintain the slopes that the three points create whilst extending to the bounding polygon. 

It has been easy to create this plane within the points, but I cannot find a way to have it continue to interpolate this plane outside of the points.

Does the community have any ideas how to achieve this? Thanks in advance.

[DanPatterson]

Were you using this tool?

Create TIN (3D Analyst)—ArcGIS Pro | Documentation

In the tool's Environments property, it should support the Extent property which could be set as a bounding constraint

[LostCarto]

Sadly, no matter what extent is set in the Environments property, the TIN is only generated within the bounds of the three points. 

[BobBooth1]

I don't know a tool that will do this for you, but if you are willing to dig into Python and feature geometry, you could calculate the z values for the vertices of the bounding polygons and use them as inputs to the triangulation.

https://stackoverflow.com/questions/52182951/getting-the-height-from-4-points-and-local-coords-at-an...