Hi, I have just joined this forum,
I am an elderly railway technician and for about a year I have been trying to familiarize myself with babylon to build my virtual railway model
http://libero51.altervista.org/Babylon/FS1950/FS1950.html
The question of tunnels, or holes in the dynamic terrain, has been solved for now with tricks that involve discrete complications of the code and its readability.
http://libero51.altervista.org/Babylon/Video/Video_0.flv
Alternatively I was able to create holes in the dynamic terrain using the property hasVertexAlpha = true, but in this