About Working with Mass Property Parameters
Creo Parametric can compute the mass properties of a part or assembly either based on the actual geometry of the object, or based on user-assigned parameter values. For example, when you create a simplified part for an assembly, you may want its mass properties to correspond to a fully detailed part. You can assign mass properties to a part or assembly either by assigning values to alternate mass parameters, or by using a mass properties file.
When working with the mass properties of a part or assembly, you can at any time generate a mass properties report based on either of the following sources:
• Geometry and Density—Calculates mass properties based on model geometry.
• Geometry and Parameters—Calculates mass properties based on the alternative parameter values. The values could be changed or assigned by mass properties file. For information how to use a file for assigning mass properties refer to related links.
• Fully Assigned—Calculates mass properties based on the alternate parameter values. The values can be changed or assigned by the mass properties file. For information how to use a file for assigning mass properties refer to related links.
When you generate a mass properties report, it is displayed in an information window and written to a file in the current working directory, named objectname.m_p, where objectname is the name of the part or assembly.
Reported and Alternate Parameters
The values generated in the mass properties report are stored in the model as its reported mass property parameters. You can view them by clicking
Tools >
Parameters and selecting
Reported Mass Properties or
Extended Reported Mass Properties from the list at the bottom of the
Parameters dialog box.
You can not modify values of reported parameters, they are derived from the last generated mass property report. To change the reported parameter values, you can specify alternate mass property parameter values and generate a report using Geometry and Parameters as the source.
If you generate a report using Geometry and Density as the source, the reported parameter values are based on the model geometry. Before you calculate model mass properties for the first time, all the reported parameter values are zero.
Alternate mass property parameters are also stored in the model. You can modify values of these parameters using either of the following methods:
• When generating the mass properties report, set the source to Geometry and Parameters or Fully Assigned and modify the values.
• Click
Tools >
Parameters and select
Alternate Mass Properties from the list at the bottom of the
Parameters dialog box. Type the parameter values in the appropriate boxes.
• Click
Tools >
Relations and add relations to the model to define the appropriate parameter values.
After you change the alternate parameter values using either of these methods, you have to make the changes reflect in the reported parameters. You can:
• Generate a mass properties report with Geometry and Parameters or Fully Assigned as the source.
• Make sure the PRO_MP_SOURCE parameter is set to PARAMETERS or ASSIGNED, and the configuration option mass_property_calculate is set to automatic, and regenerate the model.
You can use both reported and alternate mass property parameter values in relations, to drive other model parameters.
Configuring for Mass Property Computations
You can use the following configuration options when working with mass property parameters:
• To set Creo Parametric to automatically calculate all mass properties, set the configuration option mass_property_calculate to automatic. Then the reported parameters will automatically update, based on the PRO_MP_SOURCE parameter value, every time you regenerate the model.
• To include into an assembly mass property report complete listings of the mass properties of the components, set the configuration option mp_calc_level to all_models. If the report is longer than 2,000,000 characters, it is not shown on screen, but the objectname.m_p file is written to your working directory.