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Alignment from FCF Datum Shift



I think what vpt (and me) were hoping for was a way to create an alignment that uses the Xact fit shift. There are all sorts of applications for this. Using the available options in best-fit alignment is not the same, because they do not attempt to fit within a tolerance zone.

A few years old but I haven't found anything using search.

SPH1       =GENERIC/SPHERE,DEPENDENT,CARTESIAN,OUT,$
            NOM/XYZ,<0,0,0>,$
            MEAS/XYZ,<0,0,0>,$
            NOM/IJK,<0,0,1>,$
            MEAS/IJK,<0,0,1>,$
            DIAMETER/1,1.1
DIM LOC1= LOCATION OF SPHERE SPH1
AX    NOMINAL       +TOL       -TOL       MEAS        DEV     OUTTOL
D       1.0000     0.2500    -0.2500     1.1000     0.1000     0.0000 ------#--
END OF DIMENSION LOC1
            DATDEF/FEATURE=SPH1,A
            DISPLAYPRECISION/6
FCFLOC1 =POSITION : CIR152_1,CIR152_2,CIR152_3,...
            FEATCTRLFRAME/SHOWNOMS=NO,SHOWPARAMS=NO,SHOWEXPANDED=NO
              SIZE TOLERANCES/33,DIAMETER,0.375,0.005,-0.005
              PRIMARY DIMENSION/POSITION,DIAMETER,0.01,MMC,A,MMC,,
              NOTE/FCFLOC1
            FEATURES/CIR152_1,CIR152_2,CIR152_3,CIR152_4,CIR152_5,
                                CIR152_6,CIR152_7,CIR152_8,CIR152_9,CIR152_10,
                                CIR152_11,CIR152_12,CIR152_13,CIR152_14,
                                CIR152_15,CIR152_16,CIR152_17,CIR152_18,
                                CIR152_19,CIR152_20,CIR152_21,CIR152_22,
                                CIR152_23,CIR152_24,CIR152_25,CIR152_26,
                                CIR152_27,CIR152_28,CIR152_29,CIR152_30,
                                CIR152_31,CIR152_32,CIR152_33,,
            ASSIGN/V1=GETTEXT("DRF_SHIFTX",1,{FCFLOC1})
            ASSIGN/V2=GETTEXT("DRF_SHIFTY",1,{FCFLOC1})
            ASSIGN/V3=GETTEXT("DRF_SHIFTZ",1,{FCFLOC1})
            ASSIGN/V4=GETTEXT("DRF_ROTATIONX",1,{FCFLOC1})*-1
            ASSIGN/V5=GETTEXT("DRF_ROTATIONY",1,{FCFLOC1})*-1
            ASSIGN/V6=GETTEXT("DRF_ROTATIONZ",1,{FCFLOC1})*-1
            FORMAT/TEXT, , ,HEADINGS, , ;NOM,MEAS, , , , , 
DIM BEFORE= LOCATION OF CIRCLE CIR152_1
AX     NOMINAL        MEAS
X     10.153721   10.154507
Y    -27.402826  -27.405035
Z     -8.032519   -8.025360
END OF DIMENSION BEFORE
ALIGN1     =ALIGNMENT/START,RECALL:PREVIOUS,LIST=YES
              ALIGNMENT/ROTATE_OFFSET,V4,ABOUT,XPLUS
              ALIGNMENT/ROTATE_OFFSET,V5,ABOUT,YPLUS
              ALIGNMENT/ROTATE_OFFSET,V6,ABOUT,ZPLUS
              ALIGNMENT/TRANS_OFFSET,XAXIS,V1
              ALIGNMENT/TRANS_OFFSET,YAXIS,V2
              ALIGNMENT/TRANS_OFFSET,ZAXIS,V3
            ALIGNMENT/END
DIM AFTER= LOCATION OF CIRCLE CIR152_1
AX     NOMINAL        MEAS
X     10.151373   10.152161
Y    -27.394485  -27.396694
Z     -8.041472   -8.034312
D      0.376500    0.377383
END OF DIMENSION AFTER
            COMMENT/REPT,
            "Xshift:  "+V1
            "Yshift:  "+V2
            "Zshift:  "+V3
            "Rotation X:  "+V4*-1
            "Rotation Y:  "+V5*-1
            "Rotation Z:  "+V6*-1

The FCF output with datum shift is:


Using a sphere as the only datum seems to allow all 6 degrees to float. There is some small round-off error due to the numbers being used limited to the current DISPLAYPRECISION (not much).

Now what? Trying to actually use this has me baffled. I'd like to simulate the FCF output having the transformed measured coordinates evaluated against the model nominal values. The BEFORE dim has the nominals I want but the AFTER dim has the measured I want (like the FCF output). Inserting & Recalling alignments, Updating Dependent Commands (answering both yes and no) leaves me feeling like I've found my way into a rabbit hole. Maybe Profile dims behave differently?

I'm aware that some settings may influence the results: Update Dependent Commands (warning), UpdateBelowChangedAlignmentDuringExecution (registry), Ignore CAD to part (F5 settings), Allow Fine Tuning of Alignment (F5 settings). I'd really like to get this working inline without resorting to any type of external automation if possible. Can someone throw me a bone here? There's gotta be a way to get some mileage out of this.
Parents
  • I first worked on this several months ago and drew a blank but kept coming back. Tried radians - no luck. Tried using the "set" coordinates in different ways - no luck. Tried anchoring to different features - no luck. I know the developers aren't knuckleheads and there had to be some method to the madness. I can't explain why the datum shift values aren't presented in the order used (by me). But it seems to work at least for measured values. The part I had in mind for this came and left long ago. All of what I work on these days are tied to datum structures which don't give me any leeway for shifting things around. Can't say what kept drawing me back. Stubbornness, I would guess.
Reply
  • I first worked on this several months ago and drew a blank but kept coming back. Tried radians - no luck. Tried using the "set" coordinates in different ways - no luck. Tried anchoring to different features - no luck. I know the developers aren't knuckleheads and there had to be some method to the madness. I can't explain why the datum shift values aren't presented in the order used (by me). But it seems to work at least for measured values. The part I had in mind for this came and left long ago. All of what I work on these days are tied to datum structures which don't give me any leeway for shifting things around. Can't say what kept drawing me back. Stubbornness, I would guess.
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