The migration from XactMeasure commands to geometric tolerance commands attempts to automatically select the appropriate feature math option, datum math option, tolerance zone math option, and standard:
If all of the considered feature commands use least squares math, then the feature math option is LSQ. If any of the considered feature commands use different math, then the feature math option is DEFAULT.
If all of the datum feature commands use least squares math, then the datum math option is LSQ. If any of the datum feature commands use different math, then the datum math option is DEFAULT.
The tolerance zone math option after migration is always DEFAULT.
In the XactMeasure dimension, if the "GD&T standard" was set to "Custom" instead of "ASME Y14.5" or "ISO 1101," then the migrated geometric tolerance command uses the ISO 1101 standard.
Some feature commands don't have least squares datum math. They migrate to DEFAULT datum math. These include primary datum planes, secondary datum lines, tertiary datum points, and translated planes.
In some cases, you may not want to use the math types or standard PC-DMIS chooses during migration. You can control the migrated math options or standard if you create a file named fcfMigrationPreferences.json and place it in C:\ProgramData\Hexagon\PC-DMIS\2020.2\. Note that the C:\ProgramData\ folder is hidden by default.
The fcfMigrationPreferences.json file must be in the JSON format (see https://en.wikipedia.org/wiki/JSON).
Here is an example file:
{
"preferred considered feature math type": "least squares",
"preferred datum math type": "least squares",
"preferred tolerance zone math type": "least squares",
"custom standard migrates to": "ASME Y14.5"
}
When the fcfMigrationPreferences.json file does not exist (or exists but is not valid JSON), then the migrated math options are selected according to the feature command math options as described above. When the fcfMigrationPreferences.json file exists, is valid JSON, and has valid keys and values for controlling the migration, then PC-DMIS uses the math options defined by the fcfMigrationPreferences.json file.
The valid keys for the fcfMigrationPreferences.json file are:
"preferred considered feature math type"
"preferred datum math type"
"preferred tolerance zone math type"
"custom standard migrates to"
Invalid keys in the fcfMigrationPreferences.json file are allowed, but they are ignored. If the fcfMigrationPreferences.json file exists, is valid JSON, and lacks one of the valid keys, then the behavior for that key is the same as if there were no fcfMigrationPreferences.json file.
The valid values for the math type keys in the fcfMigrationPreferences.json file are:
"default"
"least squares"
"default with ISO constrained L2" (only valid for the preferred datum math type)
For any of the valid math type keys, if the value is "least squares", then the corresponding migrated math option is LSQ. For the "preferred datum math type" key, if the value is "default with ISO constrained L2", then the migrated datum math option is DEFAULT for ASME but is CL2 for ISO. For any of the valid math type keys, if the value is anything else, then the corresponding migrated math option is DEFAULT.
The valid values for the "custom standard migrates to" key in the fcfMigrationPreferences.json file are:
"ASME Y14.5"
"ISO 1101"
If the "custom standard migrates to" key is in the fcfMigrationPreferences.json file, and has the "ISO 1101" value, then custom-standard XactMeasure tolerances migrate to ISO 1101. Other values migrate to ASME Y14.5.
The valid keys and values in the fcfMigrationPreferences.json file must be in English.