Chapter 19 | Miscellaneous Topics
Create Tire Marks with Time in Draft View Mode
If you wish to prevent tire marks from appearing with the interpositions of the vehicles in draft view mode, simply select your vehicle, then left-click on the “tire marks” menu in the left side control panel, then left-click to enable “respect time."
Once this is done, you should only see the tire marks appear in agreement with the current time step of your simulation, rather than simultaneously with the interpositions.
Connecting Objects with a Chain/Rope/Bungie
If you wish to connect objects with the rope tool, first ensure that all objects are rigid bodies which can participate in the physics simulation. Left click on the “joints” menu in the left side control panel. Next, left-click on “create rope.”
Hover your mouse above the first object you wish to connect to the rope. You should see the object turn blue as conformation that it is currently selected. Left-click to connect the rope. Next, hover your mouse over the next object you wish to connect. Once it turns blue, you may left-click again to connect. Note, you can left click away from the second object to force the rope to into customized shapes. This is convenient if you need to thread your rope around various objects within your scene. When you are done with creating your rope, simply right click.
Take into consideration that your rope is actually an ensemble of coupled damped harmonic oscillators. Each link (sphere) is connected to its neighbor by a spherical joint, which has its own spring constant and damping term. Therefore, the longer your rope is, the more computational time it may take to simulate. Also, the amount by which the rope may lengthen during your simulation will depend upon a few factors, including the spring constant terms as well as your integration time step size, whereby you are likely to see greater lengthening of your rope for larger time step sizes and smaller spring constant values.
Increasing your spring constant values while decreasing your time-step size can help with simulating more rigid chain-like objects. You can access the rope properties by left-clicking on the corresponding “chain” objects in your left side control panel. Expanding the group folders allows you access the both the sphere object properties and the joint properties.
Disable Report Printout
Occasionally it is beneficial to prevent data associated with certain objects from being printed in the report. This is particularly useful for objects such as ropes, which can often have hundreds of connected sphere objects that can slow down performance. You disable the report output for a given object by first selecting your object, then left clicking on the “report” menu button in the left side control panel, and finally click on the box next to “disable.”
Vehicle Lights in Virtual CRASH 3
Note, Virtual CRASH 4 includes the ability to create volumetric lighting effects. Please see Chapter 20 to learn more about how to mount lights onto vehicles using the volumetric lighting tool.
Enable Lights
Currently vehicles in Virtual CRASH 3 can only display illuminated head and tail lights in the “Smooth + Texture” draw mode. Rendered scenes will not display illuminated lamps in Virtual CRASH 3. This feature is available in Virtual CRASH 4. Some of the vehicles in the vehicle list already have lights illuminated; however, illumination can be enabled by following these steps. In this example, we start with a Toyota Corolla hatchback model.
Left-click on the vehicle, then select the “Elements” selection type.
Left-click on lamp assembly you wish to illuminate.
Using the left-side control panel, left-click on the “faces” menu, then left-click on the “material” button. This will reveal a pull-down menu. Finally, select the appropriate light type. In this case, we selected “front light.”
Now all of the polygons within the lamp assembly mesh have the front light material property assigned to them. Note, there are many more options to choose from.
You should now see the front headlamp illuminated.
Disable Lights
If your models lights are illuminated, and you wish to disable this option, follow the same procedure as described above, where the glass material type is selected rather than a light type. This will turn off the illumination effect.
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