This is going to be the roller coaster simulator to end all coaster simulators, offering complete control over coaster designs, like in NoLimits, plus the rest of the game being what Roller Coaster Tycoon only wishes it was.

Now, I'm hoping that the coaster simulator will enable the designer to mathematically heartline the track and make it as realistic as possible, complete with a repertoire of different coaster makes and models, each with accurate G-force calculations.

Oh my god, this is the coaster simulator I've dreamed of but was too lazy, impatient, and unskilled to make myself.

I cannot begin to tell you how excited I am!!! (Except the absence of a CAD-like interface could be problematic.)

By the way, the video on the OP includes a representation of the Viper at Six Flags Magic Mountain, though not as precise a design as I'd like it to be.