if you construct a primary l2 plane if you have flatness on A Geotol wont show datum A in the dimension list. for Geotol you have to use an auto plane BFRE
if you construct a primary l2 plane if you have flatness on A Geotol wont show datum A in the dimension list. for Geotol you have to use an auto plane BFRE
You cannot measure the flatness of a constructed primary plane.
You cannot measure the flatness of a constructed primary plane.
correct, we discovered this when we migrated from 2020 R1 to 2022.1 some of our programs have constructed primary datum planes as oppose to auto planes. When we asked Hexagon about it, their reply is below. the migration tool didn't catch / convert the Datum A plane but it did flag the flatness dimension.
"Constructed Primary Datum plane, Secondary Datum Line and Tertiary Datum Point are only supported as Datums with the
Geometric Tolerance command and are
not supported for tolerancing by design (hits aren’t always available pending input feature type). With GeoTol, the default datum math is Constrained L2 and DRF’s are constrained in Orientation so the constructed datums are not needed. That said, these constructed datum features make sense for Legacy dimensioning so are still supported with Legacy."
Tangent planes is one of those things that harvard educated engineers think is a great idea to dump of the print but don't take into account that in reality measuring it isn't looking great either via an indicator or even older CMM (to say it nicely). Not to mention the machinists absolutely don't care about these gimmicks when making CNC toolpath in Mastercam. Same goes to datum shift, compound FCFs, or extreme form variation. I've seen a few prints engineers at my place put tangent plane requirement next to parallelism & ignored it completely instead just reporting parallelism to the datum instead. Anyway, 2016 cad version doesn't have this capability in the 1st place. Same went with the datum shift & other silly callouts. I do see the point of Tangent plane all right but in practice it's a non starter.
