How to make the velocity circle in the drawrange example?

Questions
1

https://threejs.org/examples/?q=draw#webgl_buffergeometry_drawrange

I want it to be round instead of a square but I couldn’t.

2

Hi!
Set vertices inside of a sphere. When a point is further, than the set radius, reflect its velocity vector via a normal, which is simply normalized and negated position of the point (I used .reflect() method of Vector3)
Thus, you’ll get something like this:

изображение
изображение1016×955 378 KB

3

Thank you so much! :face_holding_back_tears:

4

Picture:

изображение
изображение1004×860 216 KB

Demo: https://codepen.io/prisoner849/full/yLKZdgv