You can create custom property definitions for catalog part families using the Spec Editor, but these properties are not visible at the part size level within those families.
For example a part family for pipe may contain sizes from 1-12", but the Spec Editor interface will not display these custom properties in the sizes tab of the catalog editor.
** It is possible with the following workflow to populate unique property values to the part sizes at the catalog level.
When adding a custom property definition select "All Part Groups' for the add property to: option and you must fill in the default value field. Click the add button below the added properties column to include the property in all of the part families (groups) in the catalog. Click the OK button to apply the changes and then save the change to the catalog.
Here I have created a custom property "Custom1" with a default value of "Null" and a field size of 20.
Back in the Spec Editor tab we can then add part families to the specification that we are defining.
After adding the family double click the family in the top half of the dialog and you will see that the custom property "Custom1" has been added to each part size in the specification. This property can be modified at the specification level, but not at the catalog level in the Spec Editor.
In the Catalog Editor tab we can import/export the catalog family and/or size data to an Excel file.
This is extremely helpful in populating information for the catalog part sizes once they have been created in the Spec Editor, but it also enables us to re-populate the default entries for the custom parameter "Custom1" for each size in the catalog.
Select the Full catalog data export option or the resulting Excel file will only contain a list of the defined families and not their individual sizes.
In the Excel file you will have to unprotect the sheet before you can make any changes.
It is important to remember that you cannot add columns (Parameters) or rows (Sizes) into the Excel file...this data will not import back into the catalog if you do.
Note: You can safely edit most of the field in the Excel file, but you should never edit the SIZERECORDID.
When importing the modified data back into the catalog the Spec Editor will identify and highlight those changes as seen here. This allows the user to accept or reject the changes individually or globally with the tool buttons located at the top left corner of the tabular list of properties and their values.
Once they have been accepted or rejected you can click OK to apply the changes and then save the catalog.
Back on the Spec Editor tab you can "Check for Catalog Updates".
Choose to update or discard the changes as required and then save the changes to the specification before closing the Spec Editor.
You will then need to add the custom property "Custom1" to the appropriate Plant 3D Class definition.
Right click on the project name to access its properties.
This parameter will cascade down through the tree to all sub-branches...so be sure to place the custom property at the highest level of the required class.
In a 3D drawing in the plant project you can now route pipe using the specification that you just created/updated.
The properties palette will show the part size values for "Custom1" under the section titled General.