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Does anyone know an easy way to project all the points in a group to a plane?

AndersI
I have a group of points (a plane for example) and I want to project them all to a plane (simplest case == WORKPLANE). Is there some smart way to do it all at once (a.k.a. "the JEFMAN way") or is it only possible with a loop? I haven't found anything yet...

The object of this is to create a secondary tangent plane perpendicular to the primary by the following method:

- measure the secondary plane
- project all points up/down to the primary (WORKPLANE)
- construct a tangent plane from the original plane points + the projected points (guaranteed to be perpendicular to the primary as that is our projection direction)

As a follow-up question: How can I use an ARRAY variable in the same way as .HIT[...] in the construction of a tangent plane?
  • If only there was a copy/paste with pattern, as a theoretical feature. Or a copy/paste with pattern as a reference offset to the features...
  • in reply to Kp61dude!
    Being one of the persons who modded the ToPoints script, I'm not really sure it does the right thing in every situation (Running ToPoints on the hits of a cone and then constructing a new cone from that does not produce identical cones). Also, I'm looking for something that doesn't produce a command line for each point - think of scanning thousands of points, for example...
  • in reply to EmilySue
    The Adjust Filter only exists for sphere, cone and cylinder, otherwise the cut plane option of that command might have done the trick.
  • in reply to JEFMAN
    The problem in the second q. is that I can't construct a new feature from a variable array, and I'm not allowed to change the hit data in a group (at least I haven found a way to do it).
  • in reply to JEFMAN
    Unfortunately the hits of a 2D BF line still have their 3D values, the 2D is only applied to the line itself, as far as I can tell.
  • To give you an idea of what this is supposed to accomplish, here's [part of] my test program and some pictures. Just four points, creating a plane that is *not* perpendicular to the primary, projecting the four points and then creating a tangent plane (of all the points) that *is* perpendicular to the primary, touching the 'furthest' of the points of the plane: 

    
PNT2       =FEAT/CONTACT/VECTOR POINT/DEFAULT,CARTESIAN
            THEO/<38,0,-6>,<0,-1,0>
            ACTL/<38,-1,-6>,<0,-1,0>
            TARG/<38,-1,-6>,<0,-1,0>
            SNAP=NO
            REPORT VEC=<0,0,1>,UPDATE VEC=<0,0,1>
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO
PNT3       =FEAT/CONTACT/VECTOR POINT/DEFAULT,CARTESIAN
            THEO/<38,0,-29>,<0,-1,0>
            ACTL/<38,1,-29>,<0,-1,0>
            TARG/<38,1,-29>,<0,-1,0>
            SNAP=NO
            REPORT VEC=<0,0,1>,UPDATE VEC=<0,0,1>
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO
PNT4       =FEAT/CONTACT/VECTOR POINT/DEFAULT,CARTESIAN
            THEO/<180,0,-6>,<0,-1,0>
            ACTL/<180,-1,-6>,<0,-1,0>
            TARG/<180,-1,-6>,<0,-1,0>
            SNAP=NO
            REPORT VEC=<0,0,1>,UPDATE VEC=<0,0,1>
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO
PNT5       =FEAT/CONTACT/VECTOR POINT/DEFAULT,CARTESIAN
            THEO/<180,0,-29>,<0,-1,0>
            ACTL/<180,1,-29>,<0,-1,0>
            TARG/<180,1,-29>,<0,-1,0>
            SNAP=NO
            REPORT VEC=<0,0,1>,UPDATE VEC=<0,0,1>
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=NO

PLN2       =FEAT/PLANE,CARTESIAN,OUTLINE,NO
            THEO/<109,0,-17.5>,<0,-1,0>
            ACTL/[COLOR=#FF0000]<109,0,-17.5>,<0,-0.9962406,-0.0866296>[/COLOR]
            CONSTR/PLANE,TANGENT,PNT2,PNT3,PNT4,PNT5,,
            MATH_TYPE/CONSTRAINED_MINMAX,BF

[COLOR=#008080]$ this is the part I want to accomplish as one (or a few) single commands, acting on the all the points at the same time. Just think of this on a scanned plane with thousands of points...

PNT6       =FEAT/POINT,CARTESIAN,NO
            THEO/<38,0,0>,<0,0,1>
            ACTL/<38,-1,0>,<0,0,1>
            CONSTR/POINT,PROJ,PNT2,
PNT7       =FEAT/POINT,CARTESIAN,NO
            THEO/<38,0,0>,<0,0,1>
            ACTL/<38,1,0>,<0,0,1>
            CONSTR/POINT,PROJ,PNT3,
PNT8       =FEAT/POINT,CARTESIAN,NO
            THEO/<180,0,0>,<0,0,1>
            ACTL/<180,-1,0>,<0,0,1>
            CONSTR/POINT,PROJ,PNT4,
PNT9       =FEAT/POINT,CARTESIAN,NO
            THEO/<180,0,0>,<0,0,1>
            ACTL/<180,1,0>,<0,0,1>
            CONSTR/POINT,PROJ,PNT5,[/COLOR]

[COLOR=#008080]$ end of problematic area[/COLOR]

PLN3       =FEAT/PLANE,CARTESIAN,OUTLINE,NO
            THEO/<109,0,-8.75>,<0,-1,0>
            ACTL/[COLOR=#0000FF]<109,-1,-8.75>,<0,-1,0>[/COLOR]
            CONSTR/PLANE,TANGENT,PNT2,PNT3,PNT4,PNT5,PNT6,PNT7,PNT8,PNT9,,
            MATH_TYPE/CONSTRAINED_MINMAX,BF




  • in reply to AndersI
    Oh, I was so confused before this picture. I thought you were trying to create a plane perpendicular to the scan points. Now, I get it. You want to force your tangent plane to be square to the primary, ie to be a simulated datum reference plane.

    For a feature that is nominally square to the primary/DRF, you can accomplish this by finding the point with the MAX value (in Y for the example given, or T for any surface) and then use that point as the Y value of a generic plane. Then set the generic plane vectors to your given chosen vector, eg (0,-1,0) for the given example.

    For a non-square surface, you would need to find the max T value, and then again, set the generic IJK to exactly the surface's nominal vector, and use the MAX point as the XYZ of the generic plane.
  • in reply to AndersI
    That won't work, as I don't have my Y direction yet - this is the secondary datum which shall decide the Y rotation and the Y zero. And, as you can see in the picture, the actual direction of the plane is not the correct direction to look for a MAX.

    I agree that your method in most cases will be "good enough", but I'm trying to replicate "correct", i.e. the same results as putting the part on the plate (which of course is impossible, as I can't touch the full surface with a CMM, or even a scanner...).
  • in reply to EmilySue
    Gotcha. It amazes me sometimes that what seems like a straight forward concept in our brains is SO math intensive. :-/

  • Edit: Ignore me - I'm talking rubbish.

    I'll leave what's below though so you can see my (stupid) train of thought.


    I'm on an older version so don't have Tangent construction options so I'm not 100% sure how they behave, but the following might have some merits...


    This works when the 2nd plane is flat, but probably won't be perfect on an imperfect plane.

    However I'm thinking combined with your tangent construction (or possibly even a high point plane?) it might work. 

    
NT1       =FEAT/CONTACT/VECTOR POINT/DEFAULT,CARTESIAN
            THEO/<50,0,-5>,<0,-1,0>
            ACTL/<50,-1,-5>,<0,-1,0>
            TARG/<50,0,-5>,<0,-1,0>
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=YES
              AVOIDANCE MOVE=AFTER,DISTANCE=25
            SHOW HITS=NO
PNT2       =FEAT/CONTACT/VECTOR POINT/DEFAULT,CARTESIAN
            THEO/<150,0,-5>,<0,-1,0>
            ACTL/<150,-1,-5>,<0,-1,0>
            TARG/<150,0,-5>,<0,-1,0>
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=YES
              AVOIDANCE MOVE=AFTER,DISTANCE=25
            SHOW HITS=NO
PNT3       =FEAT/CONTACT/VECTOR POINT/DEFAULT,CARTESIAN
            THEO/<150,0,-20>,<0,-1,0>
            ACTL/<150,1,-20>,<0,-1,0>
            TARG/<150,0,-20>,<0,-1,0>
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=YES
              AVOIDANCE MOVE=AFTER,DISTANCE=25
            SHOW HITS=NO
PNT4       =FEAT/CONTACT/VECTOR POINT/DEFAULT,CARTESIAN
            THEO/<50,0,-20>,<0,-1,0>
            ACTL/<50,1,-20>,<0,-1,0>
            TARG/<50,0,-20>,<0,-1,0>
            SHOW FEATURE PARAMETERS=NO
            SHOW CONTACT PARAMETERS=YES
              AVOIDANCE MOVE=AFTER,DISTANCE=25
            SHOW HITS=NO
PLN2       =FEAT/PLANE,CARTESIAN,TRIANGLE,NO
            THEO/<100,0,-12.5>,<0,-1,0>
            ACTL/<100,0,-12.5>,<0,-0.9912279,-0.1321637>
            CONSTR/PLANE,BF,PNT1,PNT2,PNT3,PNT4,,
            OUTLIER_REMOVAL/OFF,3
            FILTER/OFF,WAVELENGTH=0
LIN1       =FEAT/LINE,CARTESIAN,UNBOUNDED,NO
            THEO/<100,0.5,0>,<0,-1,0>
            ACTL/<100,0.5,0>,<0,-1,0>
            CONSTR/LINE,PROJ,PLN2,PLN2,1
A1         =ALIGNMENT/START,RECALL:STARTUP,LIST=YES
            ALIGNMENT/ROTATE,YMINUS,TO,LIN1,ABOUT,ZPLUS
            ALIGNMENT/END
SCN1       =FEAT/SET,CARTESIAN
            THEO/<113.769,20.747,-7.5>,<0,0,1>
            ACTL/<113.769,20.497,-7.5>,<0,0,1>
            CONSTR/SET,BASIC,PLN1,PNT1,PNT2,PNT3,,
            ASSIGN/MINPOINTINDEX=MININDEX(SCN1.HIT[1..SCN1.NUMHITS].Y)
HIPNT      =GENERIC/POINT,DEPENDENT,CARTESIAN,$
            NOM/XYZ,<0,0,0>,$
            MEAS/XYZ,<0,SCN1.HIT[MINPOINTINDEX].Y,0>,$
            NOM/IJK,<0,-1,0>,$
            MEAS/IJK,<0,-1,0>
2NDRYPLANE =FEAT/PLANE,CARTESIAN,TRIANGLE,NO
            THEO/<0,0,0>,<0,-1,0>
            ACTL/<0,-1,0>,<0,-1,0>
            CONSTR/PLANE,PRTO,COPLANAR=NO,LIN1,HIPNT
A2         =ALIGNMENT/START,RECALL:A1,LIST=YES
            ALIGNMENT/TRANS,YAXIS,2NDRYPLANE
            ALIGNMENT/END



    By projecting the 2nd plane into the workplane to create a line, you get the i&j components but no k component. (THIS IS ABSOLUTELY NO DIFFERENCE TO ROTATING TO THE PLANE ITSELF!!)

    You can then rotate to this vector, then find max or min construct a plane perpendicular to it.

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