Mechanism Design and Mechanism Dynamics > Mechanism Design > Using Analysis Results > Playback > About the Create Motion Envelope Dialog Box
About the Create Motion Envelope Dialog Box
Click on the Playbacks dialog box to open the Create Motion Envelope dialog box after you run an analysis or restore a .pbk file. Use this dialog box to create a faceted solid motion envelope model that represents the full motion of your mechanism. You can export the motion envelope in the same manner as a standard part.
The following settings must be defined when creating a motion envelope:
Quality—Use the arrows to set a value from 1 to 10 to set the motion envelope model quality level.
Quality is inversely proportional to the size of the triangles used to create the faceted model. At a lower setting, fewer, larger triangles are created more quickly, producing a roughly accurate representation of the motion envelope. At a higher setting, many smaller triangles are created, producing a more detailed, more accurate representation. A higher quality level makes for a more complete representation but lengthens the creation time.
Best practice is to start with a low quality setting and preview the results, then gradually increase the quality level as necessary.
Components—Choose the parts, bodies, or subassemblies on your mechanism that you want to include in the motion envelope. All the components are selected by default, and the number of components is displayed in the text box. Click and deselect components to be excluded.
Special handling—The Ignore skeletons and Ignore quilts check boxes are selected by default. To use skeletons or quilts in your model when the motion envelope is created, clear these check boxes.
* For more information, search for quilts or skeletons in the Help Center
Invert triangle pairs—After you create and preview a motion envelope, click Invert triangle pairs to access these options and adjust the motion envelope. If the automatically computed motion envelope does not accurately represent the motion of your mechanism, click , and click the edge between two triangles. These triangles are replaced by the other two triangles that make up the tetrahedron defined by the triangles' four vertices.
Output format—A motion envelope can be saved in one of four formats:
Part (default)—Creates a part (.prt) file with normal geometry.
LW Part—Creates a lightweight part (.prt) file with lightweight, faceted geometry.
STL—Creates an .stl (Stereolithography) file.
VRML—Creates a VRML (.wrl) file.
* For more information, search for tessellated files in the Help Center.
Output file name—The default motion envelope file name is based on the name of the source model, in the format model_name_env0001. When the source model is a simplified representation of an assembly, the default name of the motion envelope model is simplifiedrepname_env0001. The .prt extension is automatically appended to part file names, .stl is automatically appended to STL file names, and .wrl is automatically appended to VRML file names.
Use default template—If you have specified a default template, the system uses that template, or start model, for the motion envelope part. Click File > Options > Configuration Editor to set the configuration file option start_model_dir to specify the location for the default template. Using a template as a start model allows you to include critical layers, datum features, and views in the motion envelope model. It is difficult to do this after the motion envelope model has been exported.
Click Preview for graphical and textual feedback about the information that will be captured in the motion envelope model. A shaded representation of the motion envelope model is displayed and the message window displays the number of triangles that make up the facets of the model.
When you click Create for a Part or Lightweight part output format, the system creates a solid motion envelope model. Activate this model and use File > Save to save it to a part file.
If you selected the STL or VRML output format, the system saves a .stl or .wrl file to the current working directory. The Create Motion Envelope dialog box remains open, and the source model remains in session as the current object.