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Article Number: 23 | VC6 | VC5 | VC4 | VC3 | Post Date: December 16, 2016 | Last Updated: April 15, 2024

How does one enable pedestrian, rigid body, or vehicle versus tire interactions? How can I model one vehicle climbing/driving up on another?

By default, your vehicle tire contact patches will interact only with terrain objects – either the x-y plane or 3D wireframe mesh that’s explicitly declared a terrain object via Physics > Make Terrain from Selection. This is part of the superfast optimization of the Virtual CRASH physics engine. There are instances however, when you may want the tires to interact with other rigid body objects that are not terrain objects – such as multibodies or other vehicle objects.

Vehicle versus tire interactions

An example vehicle versus tire interaction is show in the video below, which was created using Virtual CRASH 6.

To enable vehicle-tire interactions, select the vehicle with which you wish to have wheel(s) interact, and enable “contact wheels”. In our example below, because the Insight is run over by a pickup tire, we need to enable “contact wheels” for the Insight.

Modeling a climbing vehicle scenario generally requires the same workflow as a typical underride/override type scenario (see post about underride/overrides). In this case, we rotate our impulse vector’s pitch angle and modify friction and restitution as needed. Note: for each vehicle contact > preferred: manual was enabled and Create > Physics > EES Impulse was used to assign an impulse exchange at the effective point of contact. This upward directed impulse on the pickup gives the pickup an upward hop that allows the front tire to climb on the Insight’s front hood.

Multibody versus tire interactions

Below we show multibody versus tire interactions.

To enable the contact wheels option, again simply select the rigid body object you wish to have interact with vehicle wheels and go to the contacts menu in the left side control panel. This is demonstrated in the figure below. Here we first select the multibody model, then enable “contact wheels” in the left side control panel.

any rigid body versus tire interactions

In the example below, we created a simple rectangular box and converted it to a rigid body object. We then selected it and enabled “contact wheels.”

trailer versus tire interactions

To simulate vehicles atop trailers, simply select the trailer object and enable “contact wheels.”

Remember, you must enable the “contact wheels” feature for the object you wish to have interact with vehicle wheels within your simulation. For terrain objects, such as the x-y plane, or imported wireframe meshes converted to terrains via the “Make Terrain from Selection” option, Virtual CRASH automatically enables tire interactions, and so you’ll notice the “contact wheels” option missing from the contact menu.

Keep in mind the default tire model assumes that contact occurs only at the contact patch, along the local z-axis, where the tire meets with the terrain or rigid body object beneath it. If your case requires either sidewall interaction or interaction forward of the contact patch, you may want to use rigid body wheels. This video shows the process of installing rigid body wheels:

The following three examples show interacts with rigid body wheels:

Tags: Contact wheels, pedestrian run over by tire, tire-mutibody interaction, wheel interaction, running over rigid bodies

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