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8.6 Crank Slider Animation Caveats


Two caveats are applicable with the Crank Slider animation;
  1. The slide axis must be on the same relative horizontal axis as that formed by the line segment of the crank rotation and crank alignment parts when at their “zero” position. If there is a horizontal offset, the animation will not be correct.

    The code currently contains some commented out code to try to work out any horizontal displacement between the slider axis and crank rotation/crank alignment axis. This is far from finished and has been commented out to enable me to release this version of the scripts. There is an alternative way, which is to require an additional point on the slider to be selected but my gut instinct says that this is a cop out and surely there is a derivation of the horizontal displacement using trigonometry.

  2. If using the current viewing plane to derive the axis of rotation, make sure the correct one is active when the animation is run. “Interesting” animations can result otherwise.





8.7 Conclusion

Anyone is welcome to fold, mutilate or spindle these scripts to suit their own means.

If someone wants to work out the necessary logic for calculating the horizontal displacement related to the Crank Slider animation, please do so!

Please let me know if you encounter any issues with the scripts by posting to this thread.

Regards,

David
I wonder if there will be an exact solution for this area at set 8829:
[attachment=7588]

I tried to find it by hand but it seems my brain capacity is limited  Confused

/Max
(2022-02-24, 17:04)Max Martin Richter Wrote: [ -> ]I wonder if there will be an exact solution for this area at set 8829:


I tried to find it by hand but it seems my brain capacity is limited  Confused

/Max

There's some challenging angles in there (LDraw model obtained from Technicopdia) :

[Image: part_align_test_8829.png]

My code is (in effect) simply drawing circles in 2D space. Solving it for this model looks like it would need some kind of (having Google-d it earlier today) Jacobian Inverse Kinematics solver. Way beyond the capabilities of the part alignment script.

David
(2022-02-24, 22:22)David Manley Wrote: [ -> ]There's some challenging angles in there (LDraw model obtained from Technicopdia) :

My code is (in effect) simply drawing circles in 2D space. Solving it for this model looks like it would need some kind of (having Google-d it earlier today) Jacobian Inverse Kinematics solver. Way beyond the capabilities of the part alignment script.

Yikes.  Huh 1994 was certainly quite the year for this kind of stuff!

But as long as there's only a single solution, then it should be solvable just with triangles…shouldn't it? I'm sort of tempted, but I think I'll take a little break from Technic for the moment. :-)
It would be quite enough, to have solution for this.
I wonder how this was done 1994.
/Max
(2022-03-05, 12:20)Max Martin Richter Wrote: [ -> ]It would be quite enough, to have solution for this.
I wonder how this was done 1994.
/Max

I would imagine hand drawn (maybe on a computer, maybe not) since LDD pro didn't exist.
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