#### GD&T Standard

GD&T Standard area - This area provides you with a drop-down list that lets you choose what type of GD&T standard your FCF dimension will follow. Available options include ISO 8015, ISO 1101, ASME 14.5, and Custom. If you select ISO 1101 or ASME Y14.5 PC-DMIS changes different GD&T settings and calculations so that it follows the selected standard. PC-DMIS will automatically select Custom from this list if you do something that extends or customizes the previous selected standard.

ISO 1101

When you select to follow this standard, PC-DMIS applies the following changes:

It calculates the profile deviation as two times the max deviation.

It clears the Deviation Perpto Centerline check box by default. You can later select the check box if desired.

It selects the Fit to Datums check box by default. If you then clear this check box, the drop-down list will change to Non-Standard.

It calculates Axial/Radial runout according to this standard.

Coaxiality uses the concentricity symbol, a diametrical symbol precedes its tolerance, and it allows MMC/LMC on considered feature and datums.

Symmetry allows modifiers for MMC / LMC on considered feature and datums.

Material condition symbols are (for MMC), (for LMC), and a blank (for RFS).

ASME Y14.5

When you select to follow this standard, PC-DMIS applies the following changes:

- It calculates the profile deviation as (max deviation – min deviation).

- It selects the Deviation Perpto Centerline check box by default. You can later clear the check box if desired.

- It selects the Fit to Datums check box by default. If you then clear this check box, the drop-down list will change to Non-Standard.

- It calculates Axial/Radial runout according to this standard.

- Coaxiality tolerance is preceded by a diametrical symbol. It allows for MMC/LMC on considered feature and datums.

- Symmetry is only at RFS for both considered feature and datums.

- Material condition symbols are (for MMC), (for LMC), and a blank or (for RFS).

Custom

Selecting this doesn't follow a particular standard, so nothing is really changed. However, PC-DMIS will change the drop-down list to Custom and will gray out the other items, if you do any of the following:

- Attempt to dimension the parallelism of a plane with a projection length/width or diameter

- Clear the Fit to Datums check box

- Select the R symbol in the size tolerance for a position dimension.

Note: In version 4.4 and higher, you should use the GD&T Standard area to set the standard used for FCF dimensions. For legacy dimensions, you should continue to use the UseISOCalculations registry entry.