hexagon logo
Register Sign in
  • Replies 16 replies
  • Subscribers 221 subscribers
  • Views 174 views
  • Users 0 members are here
Options
Related

Problem with symmetry

Vladimir
Hello colleagues
My problem is measuring symmetry, at the moment my A_A axis is a line of midpoints at 3.45 (point J) and 21.8 (point H). This is the center of the coordinate system x=0
I built planes from two opposite sides, created a set of them and measured the symmetry, but I got very strong deviations, although the x of this plane is not so bad.
I'm afraid it's an alignment issue, as the part itself is much more complex than what I've shown, but I hope I'm just not measuring the symmetry correctly.
​
  • Have you tried creating the A-A axis from planes instead of lines?
  • in reply to TonyYaka
    no, because the coordinates of points J and H are exactly indicated in the drawing
  • something...

    FEAT/SET created from planes doesn't work for symmetry in XactMeasure.
    Probe opposing points on each of the planes.
    Use those points to create your FEAT/SET.
  • Create widths of the planes instead. Then create a common datum from A-A1. One of the datums really should be named something else than A.

    I am also questioning the use of two points as a common datum, since it seems that is not the intended usage of the part... but that could be answered by the designer.
  • something...

    FEAT/SET created from planes doesn't work for symmetry in XactMeasure.
    Probe opposing points on each of the planes.
    Use those points to create your FEAT/SET.

    I tried to do this, but the results were even worse 
    PNT_L_1    =FEAT/POINT,CARTESIAN
            THEO/<-6.1,2.231,26.215>,<-1,0,0>
            ACTL/<-6.048,2.23,26.214>,<-1,0,0>
            MEAS/POINT,1,WORKPLANE
              MOVE/CLEARPLANE
              HIT/BASIC,NORMAL,<-6.1,2.231,26.215>,<-1,0,0.0000833>,<-6.048,2.23,26.214>,USE THEO=YES
            ENDMEAS/
PNT_L_2    =FEAT/POINT,CARTESIAN
            THEO/<-6.1,7.132,24.159>,<-1,0,0>
            ACTL/<-6.228,7.129,24.16>,<-1,0,0>
            MEAS/POINT,1,WORKPLANE
              HIT/BASIC,NORMAL,<-6.1,7.132,24.159>,<-1,0,0.0000833>,<-6.228,7.129,24.16>,USE THEO=YES
            ENDMEAS/
PNT_L_3    =FEAT/POINT,CARTESIAN
            THEO/<-6.1,4.179,21.389>,<-1,0,0>
            ACTL/<-6.194,4.177,21.388>,<-1,0,0>
            MEAS/POINT,1,WORKPLANE
              HIT/BASIC,NORMAL,<-6.1,4.179,21.389>,<-1,0,0.0000833>,<-6.194,4.177,21.388>,USE THEO=YES
            ENDMEAS/
PNT_L_4    =FEAT/POINT,CARTESIAN
            THEO/<-6.1,1.235,23.689>,<-1,0,0>
            ACTL/<-6.066,1.234,23.69>,<-1,0,0>
            MEAS/POINT,1,WORKPLANE
              HIT/BASIC,NORMAL,<-6.1,1.235,23.689>,<-1,0,0.0000833>,<-6.066,1.234,23.69>,USE THEO=YES
            ENDMEAS/
PNT_R_1    =FEAT/POINT,CARTESIAN
            THEO/<6.1,3.906,26.934>,<1,0,0>
            ACTL/<6.118,3.906,26.933>,<1,0,0>
            MEAS/POINT,1,WORKPLANE
              MOVE/CLEARPLANE
              HIT/BASIC,NORMAL,<6.1,3.906,26.934>,<1,0,-0.0000833>,<6.118,3.906,26.933>,USE THEO=YES
            ENDMEAS/
PNT_R_2    =FEAT/POINT,CARTESIAN
            THEO/<6.1,1.016,23.865>,<1,0,0>
            ACTL/<6.01,1.016,23.865>,<1,0,0>
            MEAS/POINT,1,WORKPLANE
              HIT/BASIC,NORMAL,<6.1,1.016,23.865>,<1,0,-0.0000833>,<6.01,1.016,23.865>,USE THEO=YES
            ENDMEAS/
PNT_R_3    =FEAT/POINT,CARTESIAN
            THEO/<6.1,3.275,21.295>,<1,0,0>
            ACTL/<6.043,3.276,21.295>,<1,0,0>
            MEAS/POINT,1,WORKPLANE
              HIT/BASIC,NORMAL,<6.1,3.275,21.295>,<1,0,-0.0000833>,<6.043,3.276,21.295>,USE THEO=YES
            ENDMEAS/
PNT_R_4    =FEAT/POINT,CARTESIAN
            THEO/<6.1,6.104,23.793>,<1,0,0>
            ACTL/<6.006,6.106,23.794>,<1,0,0>
            MEAS/POINT,1,WORKPLANE
              HIT/BASIC,NORMAL,<6.1,6.104,23.793>,<1,0,-0.0000833>,<6.006,6.106,23.794>,USE THEO=YES
            ENDMEAS/
SCN2       =FEAT/SET,CARTESIAN
            THEO/<0,3.635,23.917>,<-1,0,0>
            ACTL/<-0.045,3.634,23.917>,<-1,0,0>
            CONSTR/SET,BASIC,PNT_L_1,PNT_R_1,PNT_L_2,PNT_R_2,PNT_L_3,PNT_R_3,PNT_L_4,PNT_R_4,,
DIM SYM1= SYMMETRY OF SET SCN2 TO LINE LIN_AA    UNITS=MM ,$
GRAPH=OFF  TEXT=OFF  MULT=10.00  OUTPUT=BOTH
AX    NOMINAL       +TOL       -TOL       MEAS        DEV     OUTTOL
M        0.000      0.010      0.000      8.162      8.162      8.152 -------->​
  • Create widths of the planes instead. Then create a common datum from A-A1. One of the datums really should be named something else than A.

    I am also questioning the use of two points as a common datum, since it seems that is not the intended usage of the part... but that could be answered by the designer.

    Yes, I would try that, but I can't figure out why when creating a width, I never see anything in the element selector


  • I managed to do this with lines built from points, apparently, but this only works on the same level with the AA centerline, I need to take a closer look at my alignment. 
    PNT3       =FEAT/POINT,CARTESIAN
            THEO/<6.1,0,20>,<1,0,-0.0000833>
            ACTL/<6.068,0,19.999>,<1,0,-0.0000833>
            MEAS/POINT,1,WORKPLANE
              MOVE/CLEARPLANE
              HIT/BASIC,NORMAL,<6.1,0,20>,<1,0,-0.0000833>,<6.068,0,19.999>,USE THEO=YES
            ENDMEAS/
PNT6       =FEAT/POINT,CARTESIAN
            THEO/<6.1,0,24>,<1,0,-0.0000833>
            ACTL/<6.032,0.001,24.001>,<1,0,-0.0000833>
            MEAS/POINT,1,WORKPLANE
              HIT/BASIC,NORMAL,<6.1,0,24>,<1,0,-0.0000833>,<6.032,0.001,24.001>,USE THEO=YES
            ENDMEAS/
PNT11      =FEAT/POINT,CARTESIAN
            THEO/<-6.1,0,20>,<-1,0,0.0000833>
            ACTL/<-6.1,-0.001,19.999>,<-1,0,0.0000833>
            MEAS/POINT,1,WORKPLANE
              MOVE/CLEARPLANE
              HIT/BASIC,NORMAL,<-6.1,0,20>,<-1,0,0.0000833>,<-6.1,-0.001,19.999>,USE THEO=YES
            ENDMEAS/
PNT12      =FEAT/POINT,CARTESIAN
            THEO/<-6.1,0,24>,<-1,0,0.0000833>
            ACTL/<-6.068,-0.002,24.001>,<-1,0,0.0000833>
            MEAS/POINT,1,WORKPLANE
              HIT/BASIC,NORMAL,<-6.1,0,24>,<-1,0,0.0000833>,<-6.068,-0.002,24.001>,USE THEO=YES
            ENDMEAS/
LIN1       =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
            THEO/<6.1,0,20>,<0.0000674,0,1>
            ACTL/<6.068,0,19.999>,<-0.008818,0.0000823,0.9999611>
            CONSTR/LINE,BF,3D,PNT3,PNT6,,
            OUTLIER_REMOVAL/OFF,3
            FILTER/OFF,WAVELENGTH=0
LIN2       =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
            THEO/<-6.1,0,20>,<0.000056,0,1>
            ACTL/<-6.1,-0.001,19.999>,<0.0081343,-0.0003252,0.9999669>
            CONSTR/LINE,BF,3D,PNT11,PNT12,,
            OUTLIER_REMOVAL/OFF,3
            FILTER/OFF,WAVELENGTH=0
SCN1       =FEAT/SET,CARTESIAN
            THEO/<0,0,22>,<-1,0,0>
            ACTL/<-0.017,-0.001,22>,<-1,0,0>
            CONSTR/SET,BASIC,LIN1,LIN2,,
DIM SYM1= SYMMETRY OF SET SCN1 TO LINE LIN_AA    UNITS=MM ,$
GRAPH=OFF  TEXT=OFF  MULT=10.00  OUTPUT=BOTH
AX    NOMINAL       +TOL       -TOL       MEAS        DEV     OUTTOL
M        0.000      0.200      0.000      0.016      0.016      0.000 #--------​
  • from my experience i think the symmetry callout in pcdmis is broken, it doesnt work correctly...
  • in reply to KatmandudaMeow
    I agree. I have never been able to get it to work correctly ether.
  • in reply to Vladimir
    I would think opposing points should be the same value in the Z axis. In CAMIO software, the opposing points for a midplane must be the exact opposite from each other. Try making all your Z values at 24. This is just my advice, I'm still learning myself.
© 2024 Hexagon AB and/or its subsidiaries. Privacy Policy | Cloud Services Agreement