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Iterative alignment and using XactMeasure

Alright here is my problem/question.
I have a part where Datum -A- (Z axis) is not prismatic, however datum -B- (X axis) and -C- (Y axis) are.

I do not have much experience with Iterative alignments other than that I have been to the Level 2 Hexagon class (Just don't use them or have the need too).

My thoughts were, this is a good time, to try an Iterative alignment.
I believe I have that part of the program correct:
I created 6 auto vector points on top (Datum -A-),
then 5 auto vector points on left side (Datum -B-)
then finally 5 auto vector points on the front of the part (Datum -C-).

When I create the Iterative alignment I pick top 6 points as level (Datum -A-),
5 points on left rotate (Datum -B-),
then 5 points on front as origin (Datum -C-).

After completing this Iterative alignment my trihedron doesn't move from before the alignment.
So I constructed planes out of the five points for datum -B- and -C- respectively.
I then origin my "X" to Datum -B- and my "Y" to datum -C-.
How do I origin my "Z", and how do I assign my datum -A- for exact measure? Where did I go wrong? Please any help would be greatly appreciated.
Parents
  • So if you have a 1-2-3 block with one hole in it 1 inch from each side and this CAD trihedron is 300 inches off in "X" and 200 inches in "Y" and I use an Iterative alignment, when I dimension my true position of said hole the nominals will be 1.00 inch each direction? Or will it be 301 inches and 201 inches.


    Both. Your dimensions will report out as X-301, Y-201, but the position will have been calculated by creating ABC at 0,0 and translating it 300,200.

    In the case of your irregular surface that is impossible to origin on, if you aren't given XYZ coordinates for say, datum B and C, then you have no way to translate the CAD. So, leave it in body position! It is ok for your nominal to not be 1,1. The calculation was done as 1,1 translated 300,200 to comply with your CAD position.
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  • So if you have a 1-2-3 block with one hole in it 1 inch from each side and this CAD trihedron is 300 inches off in "X" and 200 inches in "Y" and I use an Iterative alignment, when I dimension my true position of said hole the nominals will be 1.00 inch each direction? Or will it be 301 inches and 201 inches.


    Both. Your dimensions will report out as X-301, Y-201, but the position will have been calculated by creating ABC at 0,0 and translating it 300,200.

    In the case of your irregular surface that is impossible to origin on, if you aren't given XYZ coordinates for say, datum B and C, then you have no way to translate the CAD. So, leave it in body position! It is ok for your nominal to not be 1,1. The calculation was done as 1,1 translated 300,200 to comply with your CAD position.
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