Uncaught TypeError: Cannot read property 'x' of undefined

Hi,

I am taking bounding box of a mesh and finding center of each side. So we will have 6 points.
I am trying to add hotspot (a small button when clicked it shows some info) at these 6 points.

I am getting below error

Uncaught TypeError: Cannot read property ‘x’ of undefined
at Function.d.TransformCoordinatesToRef (babylon.js:1)
at _.i.getFacetPositionToRef (babylon.js:1)
at _.i.getFacetPosition (babylon.js:1)
at createHotspot (eval at (index.js:556), :48:21)
at s.eval [as callback] (eval at (index.js:556), :38:13)
at t.notifyObservers (babylon.js:1)
at E._checkIsReady (babylon.js:1)
at babylon.js:1

Please help me.
Thanks in advance.
PG:
https://playground.babylonjs.com/indexStable.html#988YZC#2

Well jsut a quick look but in your createHostspot, the faceId is null meaning that your position parameter is wrong

‘Undefined’ is the property of the global object. This error occurs in Chrome Browser when you read a property or call a method on an undefined object . Uncaught TypeError: Cannot read property of undefined error is probably easiest to understand from the perspective of undefined, since undefined is not considered an object type at all (but its own undefined type instead), and properties can only belong to objects within JavaScript. There are a few variations of this error depending on the property you are trying to access. Sometimes instead of undefined it will say null. If you get undefined error, you need to make sure that which ever variables throws undefined error, is assigned a value to it.