The sensor width of 22.2 mm (ie the imaging area of the Red One MX sensor, which is 24.2 mm wide) and an 18 mm lens should give you 63.322° horizontal FOV (and not the 63.653° as you mentioned, it is the exact angle of coverage of a 29 mm lens on a “leica” format i.e. the standard 24x36 mm photo format).
While most of 3D programs offer the option to set the actual film / sensor size and thus show the true focal lengths of the lenses used, it doesn’t seem to be the case with Vue. The camera in Vue doesn’t show the true focal length but the so called “Leica Equivalent” (what focal length would be needed to get the same angle of coverage using an analogue photographic camera that uses 135mm film and the above mentioned “leica” format - or an FX format digital photo camera). Well, I hope someone corrects me on this, but at least I couldn’t find the setting in Vue to change that.
For the practical purposes I’d suggest that you ignore the focal length setting in Vue and take care that you have the correct horizontal (63.322° in your case, I think) and vertical coverage angles. As long as you do that, the camera matching should go on fine. Vue will “think” that your footage was shot with a 29 mm lens on a ‘leica’ format and will give you the correct angles and there will be no difference (since it is not a physical camera, the focal length of a lens does not influence its DOF range).
BTW, the formula to calculate the (horizontal, vertical or diagonal) view angle from the width, height or diagonal of the image-covered area of sensor or film is simple and universal:
V=2atan (w/(2f))
where:
V = angle of view
w = width (or height or diagonal) of the sensor / film
f = focal length
