line dont update when position of vertexes change

[ida-fe]

code as follow:
https://codesandbox.io/s/bold-perlman-94w18o?file=/src/App.js

1. draw lines of rectangle by bufferGeometry
2. click button to change vertexes of rectangle, but dont update

is there any errors in my codes? need help

[mwmwmw]

You need to tell the BufferAttribute to update after you set the new values.

In this example, I created a ref for the geometry, and whenever the lines changes, a useEffect is called that will tell the buffer attribute to update.

https://codesandbox.io/s/update-bufferattribute-fkws1y?file=/src/App.js

[ida-fe]

It does have some effect, while In render loop，I change vertex count to 9, but dont update, code as follow:
https://codesandbox.io/s/update-bufferattribute-forked-jiezuv?file=/src/App.js