Blog | Winter 2021 Software Update
It’s time for another FREE update from the Virtual CRASH team! If you’re in the Virtual CRASH 5 (and 6) family of users, read on because this one is for you! VC4 and VC3 users, there’s a surprise for you too (see end of post).
Upcoming In-Class Training Opportunities
Easy Human Animations are here!
With the Easy Human Animation tool, you can now easily incorporate walking, running, and other motions into your visualization. To use the Easy Human Animation tool, go to Create > Animation > Human Animation. Next, left-click in the scene to create an instance of the tool, then right-click to terminate the command.
Select the male (“pedestrian”) or female model. As with the multibody, the height can be adjusted in the “size” menu.
In the “motion clips” menu, use the “category” dropdown to select the style of motion you wish to animate.
Next, in the “motion” dropdown menu, select the desired motion clip.
Next, left-click “new” and the motion clip will be added to the motion clip menu.
Left-click on the motion clip name and its various properties can be adjusted.
start at: selects the start-time within the motion clip
duration: the duration of time the motion clip will play
motion playrate: the speed at which the motion clip will play
transition loop: the amount of time to transition from the end of the current motion clip to the start of the same motion clip. This helps ensure that smooth cyclical motion repeats while using the same motion clip instance.
Increment-x,-y, and -z in the “increment” menu can be used to add cumulative displacements along the x,y, and z directions as the motion clip is playing out. For example, if the motion is walking upstairs, increment z can be used to add vertical displacement with each step.
Using the “category” and “motion” dropdowns, additional motion clips can be added to the sequence (left-click “new” to add the motion clip). Fine-tune “start at”, “transition”, and “transition loop” as needed to blend motion clips seamlessly. Transition defines the amount of time to transition from the end of the previous motion clip to the start of the current clip. Too low a value could result in abrupt arm and leg motions. Note, each motion clip can have its own global offset, controlled in the “offset” menu. For example, a step down from the sidewalk onto the street at the start of a new motion clip may require an offset-z value. A 90 degree turn to go from idle to walking may require a yaw offset of 90 degrees.
Note, the speed of the animated human can be monitored by using the diagram tool.
Baking in simulated motion
Complex simulated multibody motion, such as that from a pedestrian impact, can be incorporated into the Human Animation tool as well. The are currently two workflows to accomplish this. These are described below.
Time-forward progression
With time-forward progression, one needs to synchronize a simulated multibody to arrive at the position at approximately the same moment in time as the animated human. We start by creating an instance of a simulated multibody with pose set by the final frame in the motion clip.
Here we see a simulated multibody posed, positioned, and oriented in the same way as our animated human at the last frame of the final motion clip. Note, this multibody will be initially at rest.
If we wish for the simulated multibody to have the same speed as the animated human, we will need to start the multibody back away from the area of impact and allow it to propagate forward in time until it reaches the proper area of impact at the proper moment in time. You’ll need to ensure the multibody has no other contact interactions which may prevent it from reaching the area of impact.
Next, in the “human animation” menu under “tools”, left-click on “simulation to motion clip”, hover your mouse over the simulated multibody and right-click. This essentially “bakes” the simulate motion into a new motion clip that is appended to the end of the motion clip sequence list.
Since the simulated multibody had 4.475 seconds of pre-impact motion, here we set the “start at” to 4.475 for motion clip “multibody sim”. Now our motion clip based on simulated multibody motion will begin at the moment of impact.
The final animation can be see here:
Time-backward progression (Recommended method)
Using time-backward progression, we can ease some of the difficulty with ensuring our multibody arrives at the proper area of impact at the proper moment in time. First, we set our vehicle up at 0 speed at the area of impact at time = 0. Fine-tune the final motion clip duration value until you have the animated human arrive at area of impact at the last frame.
Then left-click on “last pose to simulation” in the human animation menu under “tools”.
Set the multibody and vehicle initial speeds as needed.
As illustrated previously, with the human animation object selected, left-click on “simulation to motion clip” in the “human animation” menu under tools, and right-click on the simulated multibody. You will then see the simulated motion clip appended to the sequence list.
Next, add kinematics to your vehicle for pre-impact motion in negative time (prior to simulation time = 0 seconds). Then adjust your human animation object’s “time offset” value until you have proper time-alignment between the vehicle and human animation object.
New data import unit options
In addition to inches, feet, miles, millimeters, centimeters, meters, and kilometers, users can import in US survey feet or in their own units. Simply select “user scale” in the “source unit” drop down and type in the conversion factor from 1 meter to your units.
New vehicles (VC5,4, and 3)
This update includes a new ambulance and fire truck. These can be found in vehicles 3d, keyword truck. VC3 and VC4 users will receive this update in late December 2021.
