Creating and Simulating a Free Body in MotionView

Welcome to the Multibody Dynamics for Automotive Applications using MotionView and MotionSolve blog series! In this post, we will walk through Exercise 2, covering essential topics such as building rigid bodies, running simulations using the Run Panel, and performing basic post-processing using HyperGraph 2D. By the end of this tutorial, you will have a solid understanding of multibody dynamics simulation, vehicle system modeling, and automotive simulation tools using MotionView software and MotionSolve software. 

Step 1: Creating a Rigid Body in MotionView 

To start, open MotionView for automotive engineers and locate the Body icon in the specific toolbar. Right-click to open the Body/Body Pair Dialog Box. Here, you can: 

• Assign a Label Name (modifiable at any stage). 
• Assign a Variable Name (fixed during creation). 
• Choose between Single Body or Body Pair. 

For this exercise, we will create a free body and name it Free Body. In multibody dynamics software, variable names should use underscores instead of spaces. Once done, click OK, and the new body will appear in the Model Browser. 

Step 2: Assigning Mass and Inertia 

Every body in multibody dynamics using MotionView requires mass and inertia properties. In the Body Panel: 

• Navigate to the Properties Tab. 
• Assign Mass = 1 kg. 
• Set diagonal matrix values: IXX, IYY, IZZ. 
• Check the Use Center of Mass Coordinate System box. 
• Select the Global Origin (0,0,0). 

Since gravity is enabled by default, expand the Forms Folder and verify that Gravity is On. 

Step 3: Running the Simulation 

To run a vehicle dynamics simulation: 

• Navigate to the Run Panel. 
• Name the simulation: Chapter 2 - Free Body. 
• Set Simulation Time = 1 second. 
• Click Run. 

Once complete, the free body will fall through space under gravity. 

Step 4: Post-Processing the Results 

To analyze the simulation results: 

• Click Plot (this divides the screen into two windows: MotionView and HyperGraph). 
• Select the Data File (ABF format). 
• Choose Body Displacement (relative to the ground). 
• Set the Y-component to Z-axis. 
• Click Apply. 

The plot will display the free body’s displacement over time. In multibody dynamics analysis, this is crucial for verifying motion behaviors. 

Step 5: Saving Models vs. Sessions 

Understanding the difference between saving a model and saving a session is essential for MotionView training and certification: 

• Model File (.mdl): Saves only the multibody dynamics modeling structure. 
• Session File (.mvw): Saves both the model and post-processing results. 
• To save a Session File, navigate to File > Save As > Session. This ensures that results remain attached to the model when reopened. 

Final Thoughts 

In this exercise, we covered how to create a rigid body, assign mass and inertia, run a simulation, and analyze results using MotionView for beginners. These steps form the foundation of automotive engineering simulation and multibody dynamics training. 

Stay tuned for our next MotionSolve tutorial for beginners, where we will explore advanced multibody dynamics essentials and automotive dynamics fundamentals! 

 This blog is part of our ongoing Multibody Dynamics blog series. If you missed the previous posts, check them out here.  

Would you like to have a more interactive experience going through the Multibody Dynamics? 

Skill-Lync has released a FREE comprehensive course covering Multibody Dynamics for Automotive Applications using Motionview and Motionsolve in detail! Check it out here.

If you’re looking to go deeper into Multibody Dynamics check out Skill-Lync’s Multibody Dynamics Course.

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