This example extends the vr_octavia example to show multiple-object scenario visualizations.

The pre-computed simulation data represent standard "Double Lane-Change" manoeuvre conducted in two vehicle configurations - with Electronic Stability Program control unit engaged and switched-off. The two sets of vehicle dynamics data is sent in parallel to the virtual reality scene, where they drive two different vehicles.

Vehicles are modelled using the VRML97 EXTERNPROTO mechanism. This means that in the main virtual world associated with the VR Sink block, it is possible to create several identical vehicles as instances of a common 3D object. This approach greatly simplifies virtual world authoring. For instance, it is very easy to create a third vehicle to simultaneously visualize another simulation scenario.

In addition to vehicle properties controlled in the vr_octavia example, vehicle prototypes allow user to define also vehicle color and scale. These properties are used to distinguish individual car instances (color) and to avoid unpleasant visual interaction of two nearly aligned 3D objects (scale). By scaling one of the cars by a small amount, one car is encompassed into another so that their faces don't clip randomly according to the current simulation data in each simulation step.

If you prefer to visualize vehicles not this way, but rather "side-by-side", it is possible to add an offset to the position of one vehicle.

Acknowledgements:

Skoda Octavia model copyright Skoda Auto, courtesy of Ismar VR, Czech Republic.