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How to make alignment based on reference touch lines and points


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Dear GOM experts.

I need to locate 3d mesh according given 4 touching lines and 2 touching points.

How can i locate the mesh in the space with these constrains?

At the beginning i can use 3 point prealignment to make rough alignment, or do best fit.

But what next ? I can see there are touching lines, cylinders but is it possible to use them as an input for further alignment?

Let me know if there is already any tutorial describing such case.

Part shall be mesured using these 6 references:



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thanks Nanno

For "Lines" i tried to use Touch Point (edge) but it was not possible to calculate RPS alignment. Always one item failed calculation. But when i used Touch Cylinder with diameter "0.0" calculation was successful and alignment looks correct now.

Is Your link correct ? When i go there i can see "User roles do not match." message.

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Hey Adam,

if you have access to our training space, you can have a look here: (eLearning) 695 Single Airfoil Measurement and Inspection  In this eLearning we are discussing alignments which have exactly the same aim as the scenario you described.

Some additional information to complete the answer:

  1. With the use of a local coordinate system you can define the edge directions for the alignment
    • image.thumb.png.39eadb82f4c1e32c4b41db53cd699b27.png
    • image.thumb.png.e6fb62216fe145788181bb29d9f61847.png
  2. When all RPS-points are constructed you can hand them over to the calculation of the RPS alignment
    • Take care to limit the points according the correct direction (e.g. 3x Y', 2x X' and 1x Z')
    • The limitation needs to follow the correct coordinate system (in the shared example it is a local coordinate system D|E|F, can be defined via 'Edit Global Constraints')
    • image.thumb.png.b049dbd88531205bad7765c17349ad9f.png
  3. Check the result/convergence of your RPS
    • All RPS points in use will have an ideal nominal element and the related actual. For the six points of the shared example the have to have now remaining deviation along the limiting direction. The remaining two dimensions of those points are allowed to be different to zero.
    • Here are the checks in the local coordinate system D|E|F of the example (3x Y', 2x X' & 1x Z' == 0.0mm):
      • image.thumb.png.469c216f9e4751d7318265ee2890a1f8.png


Hope this helps! 🙂

Gruß, Jens

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