Can't find correctly vertices of my object

[JYuan94]

Hello, friend! Can you help me see how I can solve this problem:

How do I get a vertex somewhere on the three.geometry surface?

How do I get the vertex position somewhere on the PlaneGeometry surface？

[image] I want the little red spheres, as shown here, to be on the geographic plate, not nested inside [image] I found this method on the Internet, but I was confused that I was using： [image] [image] The index above it has 393,216 points How do I get x and y to find the specified index to get the vertex position? This is my code, I hope you help me to look at, thank you!