What is 3D modelling?
and why is it used?
Why?
3D modelling is used because it's a good way to plan creations. So say you're building a rollercoaster, you can easily make changes or improvements and correct mistakes. Another reason that's fairly exclusive to the scenario of rollercoaster making, you can simulate how it'll feel for a human. If you use human subjects to test a rollercoaster, something could go wrong. Also, once you've made the rollercoaster, if you've made a mistake you have to completely start again. In turn this saves money.
Kingda Ka
This is at Six Flags Great Adventure in Jackson, New Jersey, USA. It's the worlds tallest roller coaster. If it weren't for 3D design this could've easily gone wrong.
Video Game Designs
3D modelling is also used widely in videogames.
Car Design
3D modelling is also used in car design.