I have four completed levels. All worked fine yesterday. today one of them loads with the entire fort missing.

The environment is there--terrain and sky. All the entities are there. But all the architecture is invisible--gone.

It's all still visible in WED but does not compile, apparently.

That grinding sound ???? That's me gnashing my teeth, soon to be followed by head banging.

I hadn't changed anything in that level. I commented out the changes I made in other levels since before the problem. I restarted all the software and the computer, and I can't find a solution.

I hope someone has an idea that will help.