Modelling a new sensor in Unity3D

Sorry, but I just had to ask and get some advice or suggestion, as I am totally new to Unity.

For my project we are working on automating a simple pick-and-place operation with a retro-fitted crane (sensors: IMU, Camera, Force_Torque, Proximity - Capacitive)

And we are in a bit of dilemma on which simulation framework to go for, at the moment we are using V-REP which is very simple to use and it has all of the required sensors, but however V-REP dosen't have physics as well as the scene rendering is too bad for computer vision algorithms to work (mainly in forest area, which is our workplace), So we were also thinking about AirSim, as it is launched on Unity (but still there are so many problems with it).

Unity is a very good option considering the scene rendering and physics, but it lacks one sensor which is essential for us i.e. Proximity-Capacitive. So my main question is that, is it at all possible to model such sensor within Unity, I know we could get a proximity sensor with raytracing (and giving a distance threshold as object detection), but is it possible to get a capacitance information?