How to determine a mapped point belong to which TIN(triangulated irregular network) on a terrain

Now I have a terrain which has been dealed with sandbox tool to many TINs. Suggest a point on the upper space of the terrain. If I want to map the point to the terrain, how can the mapped point in the terrain be determined to which TIN?

I am far from understanding what you want to achieve :blush:, but maybe this can be useful:

The raytest method is used to cast a ray (line) through the model and return the first thing that the ray hits.

For something this complex, we would like you to post a model file, and perhaps some screenshots showing what you wish to achieve. We also want you to at least try to solve the issue with code and if you fail, post the failing code snippet.

I think the example is as shown in the figure. There is a point Point1 above a piece of terrain. This point is mapped to the terrain to generate a point Point2. How to identify which plane Point2 is in (the plane is formed after the surface is divided).

The raytest method should return an array containing the point and the face, but I have never used it.