Dimensioning

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  • Dimensioning

    I have what I feel is certainly an easy question. Two actually.

    1) I'm measuring 2 planes parallel to each other. I want to report the Minimum distance between those planes and the Maximum distance. How so please?

    2) I've measure a circle. I want to report the Minimum size AND the Maximum size. I don't want to re-measure and recalling the feature into a contructed circle doesn't give me the option to change the evaluation method. How so please?

    Thanks in Advance.
    Last edited by cmmjdl; 10-02-2019, 03:51 PM.

  • #2
    Which version of PC-DMIS are you using?

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    • #3
      1: Is a bit more of a challenge. You can take the easy route: Best-fit planes should be a midplane when comparing all the form error of each plane, so if you measure a distance between both planes, relative to perpendicular axis, then add 1/2 the flatness variation error for each plane, you will get your max. if you do the same and subtract 1/2 the flatness error for each plane, you will get your min distance.
      Otherwise the harder method would be to extract the max/min z value of each planar point and distance them.
      Here's some sample code for easy route:
      Code:
          WORKPLANE/XPLUS
      PLN1       =FEAT/CONTACT/PLANE/DEFAULT,CARTESIAN,OUTLINE
                  THEO/<-0.4857,1.4608,0>,<0,0,1>
                  ACTL/<-0.4857,1.4608,0>,<0,0,1>
                  TARG/<-0.4857,1.4608,0>,<0,0,1>
                  ANGLE VEC=<1,0,0>,SQUARE
                  SHOW FEATURE PARAMETERS=NO
                  SHOW CONTACT PARAMETERS=NO
      PLN2       =FEAT/CONTACT/PLANE/DEFAULT,CARTESIAN,OUTLINE
                  THEO/<-1.1137,1.2155,2.5>,<0,0,1>
                  ACTL/<-1.1137,1.2155,2.5>,<0,0,1>
                  TARG/<-1.1137,1.2155,2.5>,<0,0,1>
                  ANGLE VEC=<1,0,0>,SQUARE
                  SHOW FEATURE PARAMETERS=NO
                  SHOW CONTACT PARAMETERS=NO
      DIM DIST1= 2D DISTANCE FROM PLANE PLN1 TO PLANE PLN2 PAR TO   ZAXIS,NO_RADIUS  UNITS=IN,$
      GRAPH=OFF  TEXT=OFF  MULT=10.00  OUTPUT=BOTH
      AX    NOMINAL       +TOL       -TOL       MEAS        DEV     OUTTOL
      M       2.5000     0.0020     0.0040     2.5000     0.0000     0.0000 -----#---
      DIM LOC1= LOCATION OF PLANE PLN1  UNITS=IN ,$
      GRAPH=OFF  TEXT=OFF  MULT=10.00  OUTPUT=BOTH  HALF ANGLE=NO
      AX    NOMINAL       +TOL       -TOL       MEAS        DEV     OUTTOL
      FL      0.0000     0.0020     0.0000     0.0000     0.0000     0.0000 #--------
      END OF DIMENSION LOC1
      DIM LOC2= LOCATION OF PLANE PLN2  UNITS=IN ,$
      GRAPH=OFF  TEXT=OFF  MULT=10.00  OUTPUT=BOTH  HALF ANGLE=NO
      AX    NOMINAL       +TOL       -TOL       MEAS        DEV     OUTTOL
      FL      0.0000     0.0020     0.0000     0.0000     0.0000     0.0000 #--------
      END OF DIMENSION LOC2
                  ASSIGN/MAXDIST=DIST1.M.MEAS+(LOC1.FL.MEAS/2)+(LOC2.FL.MEAS/2)
                  ASSIGN/MINDIST=DIST1.M.MEAS-(LOC1.FL.MEAS/2)-(LOC2.FL.MEAS/2)
      F1         =GENERIC/POINT,DEPENDENT,CARTESIAN,$
                  NOM/XYZ,<DIST1.M.MEAS,DIST1.M.MEAS,0>,$
                  MEAS/XYZ,<MAXDIST,MINDIST,0>,$
                  NOM/IJK,<1,0,0>,$
                  MEAS/IJK,<1,0,0>
      DIM LOC3= LOCATION OF POINT F1  UNITS=IN ,$
      GRAPH=OFF  TEXT=OFF  MULT=10.00  OUTPUT=BOTH  HALF ANGLE=NO
      AX    NOMINAL       +TOL       -TOL       MEAS        DEV     OUTTOL
      X       2.5000     0.0020     0.0020     2.5000     0.0000     0.0000 ----#----
      Y       2.5000     0.0020     0.0020     2.5000     0.0000     0.0000 ----#----
      END OF DIMENSION LOC3
      Last edited by louisd; 10-03-2019, 10:13 AM.

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      • louisd
        louisd commented
        Editing a comment
        outta time for #2, but you can construct a circle by referencing the hit values of the first circle, define it as a bore and set BF method to min circumscribed.
        repeat. invert to a bore, ref same circle hits and set BF method to max inscribed

    • #4
      1) Depends on what you really mean by DISTANCE, MIN and MAX - distance is deceptively simple in theory, while in reality quite hard/impossible to measure.


      1a) If the planes are perfectly flat, you could shoot four lines perpendicular to the midplane, at the four corners, create pierce points in both planes and check Point-to-Point distance at those four corners.

      1b) You could create a mid plane of the planes, level to that and find the hits that are closest/most distant. No guarantee though, that the MAX points of the two planes are really opposite each other (same for MIN) if the planes are not flat.

      1c) If the planes are opposing, you can construct a max inscribed (slot) or min circumscribed (stud?) WIDTH feature from them. Quite tricky to get both MAX and MIN, though.

      Variant a) depend on the planes being flat, variants b) and c) depend on where you put your hits.

      Do note that the result of a distance dimension (dist, max, min) depends on the order of the features, and the relative size/placement of the features, when the planes are not perfectly flat, or not parallel, or not the same size, or not placed exactly opposed to each other.

      2) Use the SIZE dimension. With that you can get both max inscribed and min circumscribed in the same dimension. Needs version 2017 or later (IIRC).
      Last edited by AndersI; 10-03-2019, 04:09 AM. Reason: Forum or Edge browser destroying formatting
      AndersI
      SW support - Hexagon Metrology Nordic AB

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      • #5
        2.1) Heads-up here, SIZE might or might not work as expected, depending on PC-DMIS version.
        PC-DMIS CAD++ 2o19 R1 SP11

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