SimMechanics

Choosing Visualization Options in SimMechanics

You need to make three choices to set up SimMechanics visualization:

• Visualize the machine's initial state and/or animate its motion
• Pick which kind of body shape for the machine components you want, convex hulls or equivalent ellipsoids
• Render the scene with MATLAB Handle Graphics or Virtual Reality Toolbox

You implement these choices via the Mechanical Environment Settings dialog box. From the Simulink menu bar, select Simulation, then Mechanical environment. The Mechanical Environment Settings dialog opens. Click the Visualization tab. The Visualization pane appears below the tab. Keep this dialog open so you can see the visualization options. See Mechanical Environment Settings Dialog Box in the Running Mechanical Models chapter for more information.

The sections of this chapter guide you to making the appropriate visualization choices within SimMechanics. The present section explains the why and how of visualizing the machine's initial state and animating its motion:

• Uses of the SimMechanics Visualization Tools
• Setting Up Static and Dynamic Visualization

You can find more on the body shapes in the next section:

• Rendering Body Shapes in SimMechanics

These two sections spell out the procedures for setting up the two SimMechanics visualization tools:

• Viewing Machines with Handle Graphics
• Viewing Machines in Virtual Reality

You can bypass the built-in visualization tools of SimMechanics by creating a virtual reality world of your own design to represent your machine's bodies. With Virtual Reality Toolbox, you build a custom interface from your model to the virtual world and animate its virtual bodies:

• Creating a Custom Machine Visualization

Uses of the SimMechanics Visualization Tools

The visualization tools of SimMechanics serve two distinct purposes, static and dynamic visualization. In both cases, you can change your observer viewpoint and navigate through the scene. You can change the body properties of the visualization only by changing the corresponding Body blocks in your model. Changing a body's mass, inertia tensor, and coordinate systems can change its visual rendering.

Static Rendering

Static rendering of machines in their initial state, during construction. Either choice is valid:

• Open the visualization before or while you build your model. You render each body as you add it to your model. Having a visualization tool open during model building lets you keep track of your machine parts and how they are connected. You can see unphysical or mistaken constructions before you finish the model.
• Open the visualization after you finish the model. All the bodies in the model appear together.

Dynamic Animation

Animation of machines while the SimMechanics model is running. Use this feature to watch the model's dynamics in three dimensions and visualize motions and relationships more easily than is possible with Scope blocks alone. Running Mechanical Models presents the steps for running SimMechanics models.

Setting Up Static and Dynamic Visualization

Begin configuring the Visualization pane of the Mechanical Environment Settings dialog box:

1. You can separately choose static and/or animated visualization:
• Render the static machine in its initial state by selecting the Draw machine in initial state check box.
• Animate the machine during simulation by selecting the Animate machine during simulation check box.
2. Choose the updating mode in the Update machine pull-down menu. The visualization tools reflect changes to the Simulink model by either immediate or delayed update:
• The When diagram changes option updates the visualized machine immediately upon changes to the Simulink model. For complex models, frequent visualization updates can be slow.
• The Only at Update diagram option ignores changes you make to the model until you choose Update diagram in the model window Edit menu. This option allows you to update the visualization in one step after making a large number of changes.
3. Implement your visualization choices at any time by clicking Apply. Clicking OK applies your choices and closes the dialog box. A visualization window opens.
4. Refresh the entire visual scene at any time by selecting Update diagram from the model window Edit menu.

Visualizing and Animating Machines

Rendering Body Shapes in SimMechanics