GD&T Position (Symbol)

[@printlife9016]

Thanks! That's very informative! One question, At 3:49, a dimension (slot's X position) specified 10 mm uses one side of the block as a reference. However, should the dimension be specified from datum D instead of 10 mm from the side of the block as the position callout uses datum D as a X position reference?

[@solonglife8130]

i have the same doubt as you. I normally make my basic dimension from Datum; meant in this case would be 22.26mm. i wont create a 10mm from edge as I will align the position from Datum. however i saw alot of example not start the dimension from Datum. In this case, i not sure if the measurement will measure 10mm as shown from the drawing or measure 22.26 from datum (i know this dimension not shown on drawing but one trainer told me we can make the calculation and measure that value). i not sure which way correct. Hope someone clarify it. Thanks.