How to using cpp to create speedtree in ue

[Quetzalcodename]

Hey @Joexiong11! Welcome to the Forums!

I believe what might be looking for is procedural mesh generation or geometry scripting. Here are some Epic and non-Epic affiliated guides and documentation to get you started for reference:

UProceduralMeshComponent

Geometry Script Reference

Getting Started With Procedural Mesh Generation | Inside Unreal

Non-Epic Affiliated

How to make a Custom Geometry Script Node in C++

Procedural Meshes Part 1

Good luck with your procedural trees!