New 'Vector Fields' component

[jamesleesaunders]

Summary

Create new 'Vector Fields' d3-x3d reusable component. Arrows representing flow direction. Also known as Quiver Plot or Velocity Plot.

Detail

Vector fields have many important applications, as they can be used to represent many physical quantities: the vector at a point may represent the strength of some force (gravity, electricity, magnetism) or a velocity (wind speed or the velocity of some other fluid).

Examples

• https://mathinsight.org/vector_field_overview
• https://goo.gl/images/WTSRZq
• https://goo.gl/images/zek2UY
• https://github.com/mjkaufer/3DVectorFields/
• http://bl.ocks.org/adrianturcato/cf665b7cca9f6057691a

Relevant Files

/src/component/vectorFields.js
/src/chart/vectorFieldChart.js

[jamesleesaunders]

http://onedayitwillmake.com/blog/2011/09/getting-the-angle-between-two-3d-points/

[jamesleesaunders]

@andreasplesch @JordanDelcros are you able to help me with a problem? I am trying to calculate the yaw, pitch and roll rotation angles needed to rotate a vector arrow between 2 points.

Using x3dom and Vector3 libraries.

I have put my attempts at vector calculations up on Observable here https://beta.observablehq.com/@jamesleesaunders/vector-fields but now all confused.

Any ideas?

[andreasplesch]

x3dom has a quaternion.rotateFromTo method to get the rotation, quaternion.toMatrix to convert and a matrix4f.getEulerAngles method to extract Euler angles. Hope this helps, Andreas

…

---on the phone---

On Sun, Jan 20, 2019, 10:53 AM James Saunders ***@***.*** wrote: @andreasplesch <https://github.com/andreasplesch> @JordanDelcros <https://github.com/JordanDelcros> are you able to help me with a problem? I am trying to calculate the yaw, pitch and roll rotation angles needed to rotate a vector arrow between 2 points. Using x3dom and Vector3 libraries. I have put my attempts at vector calculations up on Observable here ***@***.***/vector-fields but now all confused. Any ideas? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#47 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AF4p61BpHRRfvgdPZBCRsws3N1vNVjclks5vFJDxgaJpZM4ZVT_e> .

[jamesleesaunders]

Thanks @andreasplesch those methods look right up my street!
I'll have a play!

var point1 = new x3dom.fields.SFVec3f(0, 1, 0);   // By default cones are pointing up
var point2 = new x3dom.fields.SFVec3f(2, 1, 3);  // Point you want cone pointing towards
var qDir = x3dom.fields.Quaternion.rotateFromTo(point1, point2);

var rot = qDir.toAxisAngle();
[
   0: {x: -0.7071067811865472, y: 0, z: 0.7071067811865472}, 
   1: 0.9553166181245093
]
var transform = document.getElementById('transform');
transform.setAttribute('rotation', rot[0].x+' '+rot[0].y+' '+rot[0].z+' '+rot[1]);

var matrix = qDir.toMatrix();
[
   _00: 0.7745419205884382
   _01: 0.5345224838248488
   _02: -0.33818711911734267
   _03: 0
   _10: -0.5345224838248488
   _11: 0.2672612419124243
   ...
   _31: 0
   _32: 0
   _33: 1
]

var euler = matrix.getEulerAngles();
[
   1.0197622048947006,
   0.34498984341480937,
   -0.604060432799328,
   -2.1218304486950927,
   2.7966028101749836,
   2.537532220790465"
]

[jamesleesaunders]

Last few niggles:

• Update Vector fields component example with better data example.
• If scale > 0 crosshair axis acts funny.
• If vector coordinate numbers infinite then things go wrong.
• Observable Reference Error: x3dom not defined.
• Add unit tests for Vector component and chart.

[jamesleesaunders]

https://www.geogebra.org/m/KKB2Ndez

[jamesleesaunders]

https://mathematica.stackexchange.com/questions/110397/plotting-a-3d-vector-field-on-2d-plane

[jamesleesaunders]

https://math.stackexchange.com/questions/2870805/why-is-the-curl-of-a-function-which-looks-like-a-vortex-zero