Documentation

VR Tracer

Trace trajectory of object in associated virtual scene

Library

Simulink® 3D Animation™

Description

Trace the trajectory of an object in the associated virtual scene.

This block creates marker nodes in regular time steps either as children of the specified parent node (Parent node parameter), or at the top level of scene hierarchy (root).

You can specify one of three types of markers:

  • General shape

  • Line segments connecting object positions in every time step

  • Axis-aligned triads for orienting the trajectory in the 3–D space

Also, you can project traced object positions to a plane or to a point.

Object position input must correspond to the placement of the object in the scene hierarchy. If the traced object resides as a child of a parent object, define the parent object DEF name in the parent node field. If the traced object resides at the top of the scene hierarchy (its position is defined in global scene coordinates), leave this field empty.

The first block input vector determines the position of the marker. The second block input (if enabled by the Marker color selection parameter) represents the marker color. The second or third block input vector (depending on whether the marker color input vector is enabled) specifies the project point coordinates.

Block Parameters Dialog Box

Following is the Main pane of the VR Tracer block dialog box.

Following is the Marker Projections pane of the VR Tracer block dialog box.

Associated VRML file — VRML file name specifying the associated virtual world.

Parent node (leave empty for root) — Specify the location of the traced object in the scene hierarchy.

Marker shape — From the list, select one shape:

  • None

  • Tetrahedron

  • Pyramid

  • Box

  • Octahedron

  • Sphere

Connect markers with line segments — Select this check box to connect the traced object path with lines.

Place a triad at each marker position — Select this check box to place a triad at each marker position. A triad helps you orient the object trajectory in the x-y-z plane.

Marker scale — Specify a three-component vector that defines the scaling of predefined marker shapes and triads. This parameter allows accommodation for scenes of various sizes.

Marker color selection — From the list, select:

  • Block input — Disables Marker color parameter and relies on the second block input to define the marker color. Selecting this option enables the second block input, to which you can connect a signal for the marker color.

  • Selected in block mask from color list — Enables the Marker color parameter, for selecting one color from of a list of colors for the marker.

  • Defined in block mask as RGB values — Enables Marker color parameter to accept RGB values for the marker color.

Marker color — If Marker color selection is Selected in block mask from color list, select the color from the list: yellow, magenta, cyan, red, green, blue, white, black

If Marker color selection is Defined in block mask as RGB values, enter RGB values for the marker color.

Sample time — Enter the sample time or -1 for inherited sample time.

Ensure that a viewer window is open during simulation — Select this check box to ensure that the Simulink 3D Animation Viewer is open during simulation.

Project positions on a plane — Specify whether to display line segments from an object to a plane to approximate the trajectory of the object. If you enable this parameter, use the Projection plane equation coefficients edit box to specify the plane to which to project the position of the object. The coefficients are in the form ax+by+cz+d=0. For example, if you use the default plane equation coefficients to [0 1 0 0] for the vrtkoff_tracevrtkoff_trace model, then after you simulate the model, the object positions project to the y=0 plane.

Project positions to a point— Displays line segments from an object to a point to approximate the trajectory of the object.

  • None — (Default) No projection to a point.

  • Defined in block mask — If you select this option, enter coordinates in the Projection point coordinates edit box.

  • Defined in the block input — If you select this option, specify the coordinates of the point in the output of a block that inputs to the VR Tracer block.

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