SimMechanics

Viewing Machines with Handle Graphics

The Handle Graphics feature for viewing your machine is built into SimMechanics. It uses a special set of symbols to draw bodies and Body coordinate systems (CSs). Use of the Handle Graphics tool is explained in the following sections, Interpreting Special Handle Graphics Symbols and Manipulating the Handle Graphics Window.

Note    The Handle Graphics visualization feature is based on the Handle Graphics tools of MATLAB. Refer to the MATLAB graphics documentation for a full discussion of Handle Graphics. This section mainly focuses on features special to the SimMechanics Handle Graphics tool. Certain standard Handle Graphics features are disabled or missing in the SimMechanics window.

Choosing the Handle Graphics Visualization Tool

You choose this visualization tool in the Visualization pane of the Mechanical Environment Settings dialog:

1. In the Draw machine using menu, choose MATLAB Graphics.
2. Click Apply or OK. A Handle Graphics window opens.

Interpreting Special Handle Graphics Symbols

When SimMechanics calls the internal Handle Graphics window, it uses special conventions to render the bodies of your machine. You can control some of these conventions through the special SimMechanics options menu.

The default major features of the Handle Graphics window are

• The window displays all the machine's bodies. If a body has one of these associated surfaces, the surface is shaded red:
• Equivalent ellipsoid
• Convex hull of one or more surface patches (a triangle of coplanar points or an enclosing surface of four or more points)

• A line convex hull is a black stick figure.

• Surfaces used in marking out enclosed convex hull volumes or coplanar triangles are tiled with patches.
• Clicking a body in the Handle Graphics window causes the following:
• The rendered body changes color to yellow.
• The model window comes back to focus with the associated Body block highlighted in red.

• The mech_body_driver model from the Demos library is shown with Body1 (the fixed body) highlighted.

  

Handle Graphics Window with Body and Body Block Highlighting

Legend of Handle Graphics Symbols

The machine is rendered with two special symbols:

• The center of gravity (CG) point of each body is marked by a circle-plus symbol .
• Each Body CS is marked by coordinate axis triads. The color coding is X-Y-Z axes = RGB = red-green-blue.
  
  

Controlling the Visualization.   You can control special SimMechanics features of this Handle Graphics window by using the SimMechanics menu in the middle of the menu bar.

SimMechanics Options Menu for Handle Graphics Visualization

SimMechanics Menu for the Handle Graphics Visualization Window 

Menu Item	Function	Default
Display	Bodies, triads, patches	Selected (all)
Orientation	X-Y, Y-Z, X-Z, 3D views	X-Y
Enable Model Highlighting	Body highlighting	Selected
Enable Automatic Axis Resize	Automatically resize axes and window to fit body motion	Selected
Show Legend	Open Help browser to symbol legend

You can turn each of the features on or off by selecting the item in the menu. An active item shows a check mark.

The 3D view is trimetric, from viewpoint (1,-1,1). Enable Automatic Axis Resize automatically resizes the axes and window to fit the machine motion during the animation.

The Show Legend option opens the online Help browser to this page.

Manipulating the Handle Graphics Window

The other controls on the Handle Graphics visualization tool are standard on all MATLAB Handle Graphics windows. Refer to the MATLAB Graphics documentation for a complete presentation of how to configure Handle Graphics windows and objects.

For SimMechanics model visualizations, the Zoom in, Zoom out, and Rotate 3D functions are especially useful. Select the icon and click in the figure area to activate the function. Click, hold, and roll the figure to rotate the machine in three dimensions.

Handle Graphics Window Viewing Controls

The View menu contains the useful Camera Toolbar, also discussed in the MATLAB Graphics documentation.

Rendering Body Shapes in SimMechanics

Viewing Machines in Virtual Reality