threejs-interaction

Use THREE.Raycaster with setFromCamera after converting mouse coordinates to normalized device coordinates (-1 to 1). Call intersectObjects on your clickable meshes and read the first result's object, point, and distance properties.

Import OrbitControls from three/addons/controls/OrbitControls.js and instantiate it with your camera and renderer.domElement. Enable damping with controls.enableDamping = true and call controls.update() each animation frame.

Yes, raycasting works with touch input by reading event.touches[0].clientX and clientY, converting them to normalized device coordinates, and calling setFromCamera the same way as mouse events. Listen to touchstart on the renderer canvas.

Raycasting every mousemove against the whole scene is expensive. Throttle handlers to around 20fps, restrict intersection tests to a list of clickable objects, use layers for filtering, and substitute simple invisible collision meshes for complex geometry.

Use DragControls from three/addons with an array of draggable meshes, camera, and renderer.domElement. Disable OrbitControls during dragstart and re-enable on dragend, and constrain positions in the drag event handler if needed.