Introduction to Skyscraper

Skyscraper is an advanced first-person 3D building, city, and elevator simulator, written in C++, the project started in December 2002. It supports fully simulating 3D structures, each one in a defined "building", or simulator engine. Multiple simulator engines can be run in parallel, creating cities. Skyscraper is powered by the Scalable Building Simulator, or SBS, which is the sim engine behind each building. Buildings are written in a custom scripting language, loosely inspired by the TrueVision3D graphics engine syntax, and also Visual Basic 6, which is what Skyscraper 1.0 (2004) was written in.
Skyscraper imposes no real limits on most situations, so that it makes it possible to create buildings with hundreds or even thousands of floors, very large map environments with dozens or hundreds of buildings, and more.
In the above image, 29 simulator engines (SBS instances) are running simultaneously, each representing a fully-simulated building.