Re-creating Walk-The-Plank

[RECVEB_RA]

Hello,

I am trying to create a "walk-the-plank" virtual environment. I have made it in Sketchup 2014. The two pictures that are attached show how I would like the virtual environment to look like prior to, and after lowering the floor. Unlike the demo of walk-the-plank which also has the platform being raised, I only need the floor to be lowered. Even though I have groups in the Sketchup file, it does not seem that they transfer over into Inspector.

My question is how do I specify the "Pit" area so that when I press "1" it will be lowered, just like in the demo?

I have also posted a link to the .dae file.


Here is the code for the Walk-The-Plank demo for reference.

Thank you for your help.