Topics:

• How can the density be changed?

1. During the first mass property calculation, Pro/ENGINEER prompts for density.
2. Under Setup, Density a new density can be specified.
3. Under Setup, Material the materials file can be edited to specify density.

A relation mp_density=value can be created.

• To which directory are mass property information files written on disk?

Mass property information is written to file_name.m_p in the current working directory, where file_name is the currently active model (i.e. - topasm3352.m_p).

• How can a datum point be created at the Center of Gravity?

Create a datum point using Feature, Create, Datum, Point, Offset and select the Csys that will be referenced during mass property calculations. Assign the dimensions arbitrary X, Y, and Z values. Using Relations, Switch Dim determine the symbol names (ie d7, d8, d9) of the XYZ offset dimensions just created and Add relations to the model:

1. d7 = mp_cg_x(path,csys,path)
2. d8 = mp_cg_y(path,csys,path)
3. d9 = mp_cg_z(path,csys,path)

where (path,csys,path) is the path to the coordinate system. For more information, refer to the Pro/ENGINEER Fundamentals Guide.

• How can the parameter mp_density be used in a relation?

To use the parameter mp_density in a relation, use equations of the form mp_density=14.3

Note that the use of a single equal sign (meaning "is assigned to," as opposed to a double equal signs meaning "is equal to" as used in conditionals).

• In Family Tables, how are mass properties affected?

Instances will have unique mass properties and are calculated identically to those for generic files. To determine the mass properties of an instance, retrieve the instance and execute the mass properties by selecting Model Analysis... from the Info Drop Down Menu and selecting Model Mass Properties in the Type Input Panel.

Similarly, instances in assemblies will also reflect their mass property information (not the generic's mass properties) when calculating assembly mass properties.

• Why are Pro/ENGINEER mass property values different than hand calculations?

Pro/ENGINEER uses well-known algorithms to generate its mass properities information. Since 1988, Pro/ENGINEER has been used and tested in industries from atomic energy to aerospace to military defense with thousands upon thousands of models where accuracy and precision of advanced, three-dimensional geometric models are required. Please see the Sample Calculations section to verify some Pro/ENGINEER mass property files generated from actual models.

• How can a hard copy of the mass properties on the screen be printed?

An ASCII file partname.m_p is writen to the current working directory. This contains all the mass property information seen on the screen.

• Which mass property parameters can be used in relations/notes?

Parameters can be found in the Pro/ENGINEER Fundamentals Guide Release under the Relations section. Currently only part/assembly mass property parameters can be used in relations. Xsection and one-sided volume parameters cannot be accessed in relations or notes.

C) Upcoming Events & Training Schedule:

upcoming           Vancouver Pro/E Users Group Meeting            http://www.provan.org/
2001                  Pro/USER International Conference                 http://www.prouser.org/2000conf/index.htm