setFromCoplanarPoints( a, b, c ) {

		const normal = _vector1.subVectors( c, b ).cross( _vector2.subVectors( a, b ) ).normalize();

		// Q: should an error be thrown if normal is zero (e.g. degenerate plane)?

		this.setFromNormalAndCoplanarPoint( normal, a );

		return this;

	}
Sets the plane from three coplanar points. The winding order is
assumed to be counter-clockwise, and determines the direction of
the plane normal.

@param {Vector3} a - The first coplanar point.
@param {Vector3} b - The second coplanar point.
@param {Vector3} c - The third coplanar point.
@return {Plane} A reference to this plane.