Three.js - Width of view

You have to be precise here.

You can calculate the visible rectangular region given the camera's field-of-view, camera.fov, and a given distance, dist, from the camera.

Since the object presumably has depth, you have to pick one plane through the mesh, and do the calculation at that distance.

Here is how to calculate the visible height and width for a given distance dist from the camera.

var vFOV = THREE.MathUtils.degToRad( camera.fov ); // convert vertical fov to radians

var height = 2 * Math.tan( vFOV / 2 ) * dist; // visible height

var width = height * camera.aspect;           // visible width

three.js r.117