Article Number: 94 | VC6 | VC5 | VC4 | VC3 | Post Date: April 2, 2020 | Updated: April 2, 2020
Is it possible to simulate a tree or narrow object impact in Virtual CRASH?
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Yes, you can model collisions between any objects. Modeling a narrow object impact is described below.
Here we have a sedan going too fast for the turn, flying off the road, and colliding with a tree. We want to model the car-tree interaction.
To simplify things, we’re going to start by placing a simple cylinder object within the tree.
Here we convert the cylinder to a terrain object. This will cause the cylinder to behave as an immovable object. Note, the cylinder does not need to be connected to the terrain mesh. By using the cylinder, we can confine the contact interaction to a specific region of space. You can, of course, also make the tree a terrain object, but this may have unwanted effects such as secondary contacts between branches or leaves and the sedan.
In the cylinder’s contact menu, we set the contact model to Kudlich-Slibar. This will allow us to place the impulse centroid within the volume of the sedan to better simulate the effect of crushing (we recommend you read the various posts found here to learn more about collision modelling with Kudlich-Slibar). Using Kudlich-Slibar, we can also model the car-tree interaction using a single effective impulse exchange. Recall, the default-auto collision model (the multi-point contact model), effectively treats the interacting objects as impenetrable.
Now, select the auto-ees object in the project menu. Left-click on “previous contact” a few times to ensure you’ve selected the first impulse exchange between the cylinder and sedan. Next, left-click on “create user contact”.
Now you should see a new ees object in the project menu. Select the new ees object. Here we enable “deform” so that the sedan’s mesh will crush during the impulse exchange. Next, we disable “auto position” so that we can position the impulse centroid on the outer edge of the cylinder and within the sedan’s volume. We also adjust depth of penetration such that we obtain the desired amount of crush damage on the sedan.
Finally, we hide the cylinder from view. Here we see the final result:
Tags: narrow object impact, tree impact, pole impact.
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