Three JS MeshSurfaceSampler not sampling translated points - reactjs

Question

I am trying to create a random terrain in THREE JS using the plane geometry and randomizing the pos array using this method:
let side = 200;
const geometry = new PlaneGeometry(80, 20, side, 100);
// const material = new MeshStandardMaterial({ color: '#271033'});
let material = new THREE.MeshStandardMaterial({
roughness: 1,
color: new THREE.Color('#271033'),
flatShading: true,
});
const plane = new Mesh(geometry, material);
plane.rotation.x = - Math.PI / 2 - Math.PI / 20;
plane.position.y = - 4;
plane.position.z = - 5;
plane.castShadow = true;
plane.receiveShadow = true;
let pos = geometry.getAttribute("position");
let pa = pos.array as any;
const hVerts = geometry.parameters.heightSegments + 1;
const wVerts = geometry.parameters.widthSegments + 1;
let noise2D = createNoise2D();
for (let j = 0; j < hVerts; j++) {
for (let i = 0; i < wVerts; i++) {
const ex = 1.1;
pa[3 * (j * wVerts + i) + 2] =
( noise2D(i / 100, j / 100) + noise2D((i + 100) / 50, j / 50) * Math.pow(ex, 0) );
}
}
When I try to sample points on the mesh(so that I can place tree's or whatever at said point) the points don't seem to be valid points on the Mesh. I believe it may be return points from a plane that didn't receive the rotation/position transform, but I'm not sure.
Here is the code for the sampling:
const plane = createPlane();
plane1Sampler = new MeshSurfaceSampler(plane).build();
// add plane to scene etc...
for ( let i = 0; i < 10; i ++ ) {
const tree = await loadTree();
const _position = new THREE.Vector3();
const _normal = new THREE.Vector3();
plane1Sampler.sample( _position, _normal );
tree.scale.set(0.1, 0.1, 0.1);
tree.position.set(_position.x, _position.y, _position.z);
this.scene.add( tree );
}
Finally, here's a picture of the result, the tree's should be positioned on the first lighter purple plane. I'm not really sure what the issue here is so any help is very much appreciated! Also, the project is in React and TS.

Answer 1

For whatever reason the sampler was indeed not sampling from a plane with the translations applied. By applying the same translation to the points I was able to get valid points.
// translation applied to the plane, which for some reason the sampler doesn't take into account
_position.applyAxisAngle(new Vector3(1, 0, 0), - Math.PI / 2 - Math.PI / 20);
_position.y -= 6.1;
_position.z -= 5;