Creating Stepped Plane Datum

[[Pa...]]

Hello Calypso Community!  New CMM here struggling extremely hard with a program I'm trying to write.  (Basic is next week, I'm completely self taught thanks to youtube and other resources.)  

I have to measure various hole positions on this drawing, and my datums are listed as shown.  I am not sure how to set up Datum A.  It gives three points for Y-control, but A1 and A2 are Y=51, while A3 is Y=35.  The other thing that is throwing me off, and it may be nothing, but Datum C is an angled surface.  

Using Calypso 2021, no GD&T package.

I suspect the answer lies somewhere in Geometry Best Fit, but I have no idea how to set up anything regarding that.  Any help is appreciated, and use small words please.  

 

[[Ky...]]

Hello Patrick,

 

I want to say the best option here would be to use and offset plane (if you are in North America, you can reference this document for some more detail on that: https://portal.zeiss.com/knowledge-base?id=634895).

 

It only allows you to recall 3 points, so what I would probably do is measure A1 and A2 as planes and then use the recall option to recall them into single points (not recall feature points, but just recall the plane). In the end, you should have an A1 plane, an A1 point (made from recall), an A2 plane and an A2 point (again made from recall). For A3, I would probably create a "Point with point set" (that you can find in CAD>Creating features and go under the Point Set tab) to create A3. Then you can use the document above to create the offset plane.

 

One thing I would watch out for, though, is that the resulting plane doesn't look like it is going to have a lot of width relative to it's length. This may cause some repeatability issues, but this is something you would have to watch out for after making the program.

 

Hope that is useful.

[[Ma...]]

I am using points instead of planes - in strategy you can specify points inside of defined radius. Often on drawings there are specified datums with diameter.

[[Pa...]]

Thank you for your responses!  Out of curiosity, why would you use a "Point with point set" for A3 instead of the same method as A1 and A2?  I'm struggling creating the point with point set, as I have never done that before.  

As for capturing these datums, I'm using a circle path (set to 10mm dia.) on the planes approximately where the drawing indicates.  I am pulling B1 and B2 into a single plane using "Recall feature Points"  Is this the correct way to do this?

[[Ky...]]

Mostly so you wouldn't have to recall A3 into a point after measuring it as a plane. There isn't much of a way around it for the other 2 (since they have a borehole in the middle), but the point with point set lets you measure an area and use that data as a point.

 

For your other question, I would use just normal recall. I think it might still work okay with recall feature points, but I think recall makes more sense here.

[[Ky...]]

Other thought, and I did think about this on Friday but forgot to mention it, perhaps this actually wants to be an RPS alignment? If you are asked to use -A- as a datum by itself, I would probably still do this, but if its all A|B|C, then you might want to look into that. You can read up more on it here:
https://portal.zeiss.com/knowledge-base?id=484141
(I know if says airfoils, but it should still be applicable here).

 

This document may also help a bit. It also shows another way to measure that point with a point set rather than going to CAD>Creating features:
https://portal.zeiss.com/knowledge-base?id=1541051

Edited 23 hours ago

[[Pa...]]

It is indeed all A|B|C.  I'll take a look into that.  Thank you Kyle, you have been amazing!