Minelab 8000

[Aziz]

Hi all,

now added multi path definition feature. A coil can consist of several individual parts.
Move, scale and rotate on section is also implemented.

Dilatation and contraction of wire path referred to its reference is also important.
I have maybe implemented 50 % of the required features.

[Aziz]

Dilatation and contraction is very important as a coil bundle can't be really realised with scale only commands.
And I am also thinking of cubic spline interpolation feature for coils. A better coil geometry and accuracy can be realised.

Oh man!, it is more than 34 years ago I have done cubic spline interpolations (in the exam!).
This might be a good job for AI coding...

[Aziz]

Yep, I really need 3d-cubic spline interpolation. This is a must-have feature.
We can model complex fusion reactor coil arrangements with it..

There we have the next evolution and slight changes:
I have to distinguish between a wire path (physically existing wires, implemented in the current version) and a geometric path (which does not create any wires). From the geometric path definition, I can create the smooth wire path finally.

Let me think of it further.
Thinking. Changing. Implementing. Testing.

[Aziz]

WTF, how to contract and dilatate a path?

I have finally found the implementation of the dilatation and contraction algorithm part (already implemented in 2024).
This is beeing used for magnetic flux calculation of the single wire element.
dir = 0: calculate magnetic flux up to the center axis of wire element
dir = 1: up to the outside of the wire element (dilatation)
dir =-1: up to the inside the wire element (contraction)
pLeiter->LeiterR is the dilatation/contraction distance (wire radius in this case).

I think, I can reuse the code section.

      // 2024 neu: Winkelabhängigkeit wird berücksichtigt
      //
      VEKTOR _dse, _R1e, _R2e;
      double a1, a2, tan2a1, tan2a2, rx1, rx2;

      VekCopy(_dse, pLeiter->ds);
      EinheitsVektor(_dse);

      VekCopy(_R1e, _R1);
      EinheitsVektor(_R1e);

      VekCopy(_R2e, _R2);
      EinheitsVektor(_R2e);

      a1 = _PI_H - acos(-SkalarProdukt(_R1e, _dse));
      a2 = _PI_H - acos( SkalarProdukt(_R2e, _dse));
      tan2a1 = tan(a1);
      tan2a1 *= tan2a1;

      tan2a2 = tan(a2);
      tan2a2 *= tan2a2;

      rx1 = pLeiter->LeiterR * sqrt(1.0 + tan2a1);
      rx2 = pLeiter->LeiterR * sqrt(1.0 + tan2a2);

      VekAddSkalarMul(_R1, _R1, rx1*dir, _R1e);
      VekAddSkalarMul(_R2, _R2, rx2*dir, _R2e);
​

Don't ask me what I have did. I don't know anymore.
But it speeds up the implementation.

AI totally sucks! It can't do it.

[Aziz]

Well ok,

dilatation/contraction of a path needs a more accurate solution.

This elliptical coil is done with duplicate scale modifier. Note, that the bundle thickness scales too.

And this is done with dilatate/contract modifier. The bundle thickness stays same.

But the latter one produces inaccurate wire locations.
Back to the black board.
AI, why don't you do that?

[Aziz]

Hi all,

well, the very basic dilatation/contraction variant could still be enough to use it. Slight model inaccuracy on special shaped coils won't really matter much.
For circular coils, there won't be any inaccuracy.

The wire element start and end point locations are consistent.
We can define each wire path individually for more accuracy without using the dilatate and contraction function at all.

I'll look for another solution with better results.

[Aziz]

I am probably soon able to model the GPZ 7000 Super-D/X-coil. All this development effort was just made to be able to model any shaped coils.