TP of B back to A and C???

[[Ma...]]

I am trying to figure out what my nominals would be if C was dimension back to A and B and B to A and C? I would think since B1 and B2 control rotation, you would only have one value in my case the Z distance from that B Datum the dimensioning Datum B to A and C...not sure.  How would I set this up?

[[Ma...]]

I think - datum B is stopping rotation and also gives you origin in one axis. Unless you have RPS table telling you dimensions.

[[Ma...]]

So in this case I would be right in I would get a one directional Position, Since my origin is B and C intersect I would only get one value and the other would be zero as there is no deviation in one direction, the Origin is C, am I understanding what you're saying? The RPS is not dimensioned to the datums.

 

Edited January 15

[[Ma...]]

There is no base dimension from C to B, but CAD model will provide that.

I assume for TP callout from datum A|C will be C your origin ( intersected with A )

[[Ma...]]

Yes for the call-out for Datum B to A/C yes, that one is pretty straightforward as far as pulling the nominal dimensions from C to B1 and B2, not sure how rotation is controlled but I get the idea two planes 90° (A and C) intersecting, so I got the X and Z nominals off of the Cad, but the C to AB is still a little odd, I would assume the same notion two 90° planes intersecting at A Plane and B Line but where is the origin in that? This is what I got but I question if its correct.

[[Ma...]]

Those datums B and C - are they circles or how is looking their shape?

If datum B is only symmetry of planes in Z, then you can not do TP for C and same for TP for B

[[Ma...]]

They are symmetry points and then a 3D line as they are a unique shape, can't really get a circle or cylinder off of them. Datum B1 and B2 are called back to A and C and Datum C is called back to AB, so I was thinking A and B intersect but you only get one direction as there is nothing controlling translation, for B back to AC, the origin is the intersecting planes of A and C but nothing really controlling rotation, I am using lines and points but as it was designed I am picturing the features as orthogonal planes. Does that make sense? Like in this example. I am not sure how else to set this call-out up and welcome any suggestions. 

[[Ma...]]

For me is not making sense any of those TP.

For C you would need to have only in X direction, which can not be given by datum B and for B's - they need controling in Z, but C is giving X.

I would ask customer/engineer how they ment this to be measured.

[[Ma...]]

If they were measured as circles...I realize they are not but center is center. 

[[Ma...]]

So if we did use circles would only get an X Value for TP of B1 back to AC? Two intersecting planes would only get an X value right?

 

[[Ma...]]

For that it should give you only one axis ( not sure which one in this case ) but the other axis should be fine, because it should rotate measured feature to nominal value.

So if you have measured feature to be [X+20] and Y-20 ( X is base dimension ) then it should rotate to have X exactly X+20, then Y won't be exact -20