Y position at a certain x position of a moving tubegeomerty

Questions
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2

You should not constantly create new objects in animate.

new THREE.Raycaster()
(new THREE.Vector3(x, 0, 0), new THREE.Vector3(0, 1, 0))

You can create them once and then use them.

Take a look at the beginner example step 10 from the collection.

see also
RaycastingToLine
RaycasterAfterUpdatingPositions