Change Default/Create Custom Raycaster

[Dhall88]

I'm attempting to scene where the default perspective camera follows a landscape heightmap. I've done this in past with Threejs by setting the casting direction to shoot directly below the camera:

let castOrigin = new THREE.Vector3();
let castOrigin.copy(camera.position);
let castDirection = new THREE.Vector3(0,-1,0);
castOrigin.y =+ 100;
raycaster.set(castOrigin,castDirection);
// Check intersects and adjust camera.position.y to suit

Is there an equivalent in fiber? At the moment, my manual attempts to set the direction in useFrame() are overwritten by any mouse movement.

[drcmda]

you can use your own raycaster. the default raycaster is for pointerevents.