Cone problem

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Cone problem

    I often have to measure short cones / large diameter.
    I noticed than measuring or constructing a cone with a length of 1 mm gives strange results, and if I change from 1 to 2 mm, results arebetter.
    I can't post a real case here, but I created a case which shows the problem.
    I constructed a BF cone from 2 ellipes (circles with a little defect !). I used BF because I can't easily construct a circle from hits in this case.

    Code:
    ELL1       =FEAT/CONTACT/ELLIPSE/DEFAULT,CARTESIAN,IN
                THEO/<0,0,0>,<0,0,1>,300.05,300,<1,0,0>
                ACTL/<0,0,0>,<0,0,1>,300.05,300,<1,0,0>
                TARG/<0,0,0>,<0,0,1><1,0,0>
                START ANG=0,END ANG=0
                SHOW FEATURE PARAMETERS=NO
                SHOW CONTACT PARAMETERS=NO
    ELL2       =FEAT/CONTACT/ELLIPSE/DEFAULT,CARTESIAN,IN
                THEO/<0,0.005,1>,<0,0,1>,300.5,300.45,<1,0,0>
                ACTL/<0,0.005,1>,<0,0,1>,300.5,300.45,<1,0,0>
                TARG/<0,0.005,1>,<0,0,1><1,0,0>
                START ANG=0,END ANG=0
                SHOW FEATURE PARAMETERS=NO
                SHOW CONTACT PARAMETERS=NO
    SCN3       =FEAT/SET,CARTESIAN
                THEO/<0,0,0.5>,<0,0,1>
                ACTL/<0,0.0025,0.5>,<0,0,1>
                CONSTR/SET,BASIC,ELL1.HIT[1..20],ELL2.HIT[1..20],,
    CON1       =FEAT/CONE,CARTESIAN,OUT,LENG,NO
                THEO/<0,-0.7246,-666.5177>,<0,0.0010375,0.9999995>,1.3115,299.9538,300.5441
                ACTL/<0,-0.7253,-666.5189>,<0,0.0010385,0.9999995>,1.3118,299.9537,300.5442
                CONSTR/CONE,BF,SCN3,,
    CE1        =FEAT/CIRCLE,CARTESIAN,IN,NO
                THEO/<0,-0.0326,0.5>,<0,0.0010375,0.9999995>,300.2499
                ACTL/<0,-0.0326,0.5>,<0,0.0010385,0.9999995>,300.2499
                CONSTR/CIRCLE,CONE,CON1,HEIGHT,0.5,REF_POINT = ORIGIN,REF_VECTOR = ZPLUS
    F2         =GENERIC/PLANE,DEPENDENT,CARTESIAN,$
                NOM/XYZ,<0,0,0.5>,$
                MEAS/XYZ,<0,0,0.5>,$
                NOM/IJK,<0,0,1>,$
                MEAS/IJK,<0,0,1>
    V3         =LOOP/START,ID=YES,NUMBER=20,START=1,SKIP=,
                  OFFSET:XAXIS=0,YAXIS=0,ZAXIS=0,ANGLE=0
                  ASSIGN/V4=UNIT(ELL1.HIT[V3].XYZ-ELL2.HIT[V3].XYZ)
                  ASSIGN/V5=DOT(ELL2.HIT[V3].XYZ-F2.XYZ,F2.IJK)
                  ASSIGN/V6=DEG2RAD(180-ANGLEBETWEEN(V4,F2.IJK))
                  ASSIGN/V7=ELL2.HIT[V3].XYZ+((V5*V4/COS(V6)))
    F3           =GENERIC/POINT,DEPENDENT,CARTESIAN,$
                  NOM/XYZ,<V7.X,V7.Y,V7.Z>,$
                  MEAS/XYZ,<V7.X,V7.Y,V7.Z>,$
                  NOM/IJK,<0,0,1>,$
                  MEAS/IJK,<0,0,1>
                  ASSIGN/V9[V3]=V5
                LOOP/END
    SCN6       =FEAT/SET,CARTESIAN
                THEO/<0,0.0025,0.5>,<0,0,1>
                ACTL/<0,0.0025,0.5>,<0,0,1>
                CONSTR/SET,BASIC,F3[1..20],,
    CE2        =FEAT/CIRCLE,CARTESIAN,IN,LEAST_SQR,NO
                THEO/<0,0.0025,0.5>,<0,0,1>,300.25
                ACTL/<0,0.0025,0.5>,<0,0,1>,300.25
                CONSTR/CIRCLE,BF,2D,SCN6,,
                OUTLIER_REMOVAL/OFF,3
                FILTER/OFF,UPR=0
    CE1 is the circle constructed from cone at 0.5 mm of origin, and with ref vector as ZPLUS. Why does the vector of the circle isn't <0,0,1> ?
    CE2 is constructed from intersection of a line between hits of each ellipse and a plane F2 at Z0.5 mm.
    The center seems to be right (half of the Y defect of Ell2), and the center of CE1 is far from it...
    Could it be a bug ? If I change the Z of ELL2 to 10, both centers are close together.
    (I know that CE2 doesn't represent exactly the intersection of a cone and a plane, so it's logical that results can be different, but not like this !!!!!)

  • #2
    SCN3 Y actual value vs theo 0/0.0025
    SCN6 Y are the same 0.0025/0.0025
    My guess

    Comment


    • #3
      Strange, trying to replicate I only got this far, when the numbers started to differ from yours - you may have to show all hidden numbers in the ellipses, too? And the exact constructions used… And PC-DMIS version...

      Code:
      ELL1       =ELEM/KONTAKT/ELLIPS/STANDARDVÄRDE,REKTANGULÄRA,INRE
                  TEOR/<0,0,0>,<0,0,1>,300.5,300,<1,0,0>
                  MÄTT/<0,0,0>,<0,0,1>,300.5,300,<1,0,0>
                  MÅL/<0,0,0>,<0,0,1><1,0,0>
                  STARTVINKEL=0,SLUTVINKEL=0
                  VISA ELEMENTPARAMETRAR=NEJ
                  VISA KONTAKTPARAMETRAR=NEJ
      ELL2       =ELEM/KONTAKT/ELLIPS/STANDARDVÄRDE,REKTANGULÄRA,INRE
                  TEOR/<0,0.005,1>,<0,0,1>,300.5,300.45,<1,0,0>
                  MÄTT/<0,0.005,1>,<0,0,1>,300.5,300.45,<1,0,0>
                  MÅL/<0,0.005,1>,<0,0,1><1,0,0>
                  STARTVINKEL=0,SLUTVINKEL=0
                  VISA ELEMENTPARAMETRAR=NEJ
                  VISA KONTAKTPARAMETRAR=NEJ
      SCN3       =ELEMENT/GRUPP,REKTANGULÄRA
                  TEOR/<0,0.0025,0.5>,<0,0,1>
                  MÄTT/<0,0.0025,0.5>,<0,0,1>
                  KONSTR/GRUPP,ALLMÄN,ELL1.HIT[1..ELL1.NUMHITS],ELL2.HIT[1..ELL2.NUMHITS],,
      KON1       =ELEMENT/KON,REKTANGULÄRA,YTTRE,LÄNGD,NEJ
                  TEOR/<0,-0.3133,-1313.3429>,<0,0.0002373,1>,1.0837,300.2369,300.4846
                  MÄTT/<0,-0.3082,-1313.3284>,<0,0.0002334,1>,1.0826,300.237,300.4845
                  KONSTR/KON,BA,SCN3,,
      CIR1       =ELEMENT/CIRKEL,REKTANGULÄRA,INRE,NEJ
                  TEOR/<0,-0.0016,0.5>,<0,0.0002373,1>,300.3625
                  MÄTT/<0,-0.0015,0.5>,<0,0.0002334,1>,300.3625
                  KONSTR/CIRKEL,KON,KON1,HÖJD,0.5,REF_PUNKT = NOLLPUNKT,REF_VEKTOR = ZPLUS
      Last edited by AndersI; 09-12-2019, 07:53 AM.
      AndersI
      SW support - Hexagon Metrology Nordic AB

      Comment

      Related Topics

      Collapse

      Working...
      X