This is a post by Cat McClintock on the PTC site.
Real-time simulation is a software technology that provides instant thermal, modal, and structural analysis to designers as they work on their 3D CAD models.
Here’s how it might work. Imagine you’re updating a bike design. Older models of the bike could easily carry 125 kg (275 pounds), but product reviewers complained that it was heavy and slow. Your job is to make a lighter vehicle, without losing too much of the bike’s strength.