Trying to find documentation for Vector Field Class.

Replies to This Discussion

Permalink Reply by Ángel Linares on August 8, 2012 at 6:59am

Found with reflector: GH_Field, GH_LineCharge and so on. ;) I Suppose that I must search in GH SDK :)

Permalink Reply by David Rutten on August 8, 2012 at 9:28am

For now yes. I'll upload new SDK documentation someday soon.

--

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Vicente Soler on August 8, 2012 at 11:57am

Nice find, it's seems pretty straight forward to use. This code should do something random, no inputs required:

 


Dim size As New interval(0, 10)
Dim bx As New box(plane.WorldXY, size, size, size)
Dim rnd As New random(666)
Dim field As New gh_field
Dim crvlist As New list(Of curve)

For i As Integer = 1 To 100
Dim pc As New gh_pointcharge
pc.Charge = rnd.NextDouble
pc.Location = bx.PointAt(rnd.NextDouble, rnd.NextDouble, rnd.NextDouble)
field.Elements.Add(pc)
Next

For i As Integer = 1 To 500
Dim p As New point3d(bx.PointAt(rnd.NextDouble * 0.5 + 0.25, rnd.NextDouble * 0.5 + 0.25, rnd.NextDouble * 0.5 + 0.25))
Dim pts As point3dlist = field.SolveSteps(p, 0.1, 30, gh_differentialsolver.RungeKutta4)
Dim crv As nurbscurve = nurbscurve.CreateInterpolatedCurve(pts.ToArray, 3)
crvlist.add(crv)
Next

a = crvlist


Permalink Reply by Ángel Linares on August 8, 2012 at 12:01pm

I'm playing with it too :) Have you tried to input a merged field into a custom VB component in GH? It always gives me an error talking about that reference value is a List of GH_Fields and I cannot convert it into GH_Field.

:)

Permalink Reply by Vicente Soler on August 8, 2012 at 12:07pm

Try this:

    field.Elements.AddRange(x)

 

Permalink Reply by Ángel Linares on August 8, 2012 at 12:27pm

Didn't work :S "La expresión no genera ningún valor" at AddRange line.

Dim field As GH_Field
Dim origin As Point3d
Dim force As Vector3d
Dim pt_list As List(Of Point3d)
Dim iterations As Integer = I

field = field.Elements.AddRange(F)

origin = P
For i = 0 To iterations - 1
pt_list.Add(origin)
force = field.TensorAt(origin)
origin = force + origin
Next

Pa = PolylineCurve.CreateControlPointCurve(pt_list)

Permalink Reply by Ángel Linares on August 8, 2012 at 12:36pm

The file I'm playing with.

Attachments:

• test.gh, 3 KB

Permalink Reply by Vicente Soler on August 8, 2012 at 12:46pm

This should work:


Dim field As New GH_Field
Dim origin As Point3d = p
Dim force As New Vector3d
Dim pt_list As New List(Of Point3d)
Dim iterations As Integer = I
'Dim part_path As PolylineCurve

field.Elements.AddRange(F)
For i = 0 To iterations - 1
pt_list.Add(origin)
force = field.TensorAt(origin)
origin = force + origin
Next

Pa = PolylineCurve.CreateControlPointCurve(pt_list)


 

Permalink Reply by Ángel Linares on August 8, 2012 at 1:13pm

Ok...here it is (thanks Vicente for your help), the code for a component that draws the path of a moving particle. 

Dim field As New GH_Field
Dim origin As Point3d = Nothing
Dim force As New Vector3d
Dim pt_list As New List(Of Point3d)
Dim iterations As Integer = I
Dim particle As New GH_PointCharge

particle.Location = P
particle.Charge = 1

origin = particle.Location()

If origin = Nothing Then Return

'Dim part_path As PolylineCurve
field.Elements.AddRange(F)
field.Elements.Add(particle)

For i = 0 To iterations - 1
pt_list.Add(origin)
force = field.TensorAt(origin)
origin = force + origin
Next
Pa = PolylineCurve.CreateControlPointCurve(pt_list)

End Sub

Permalink Reply by Ángel Linares on August 8, 2012 at 3:39pm

An updated version with some extras.

Attachments:

• Particles 001.gh, 6 KB

Permalink Reply by Vicente Soler on August 8, 2012 at 3:51pm

I'm not sure but I think what you are trying to do is the same that can be done using the gh_field.solvestep and gh_field.solvesteps methods. These use more math savvy methods like euler and runge-kutta to solve the differential problem, instead of just adding a tiny increment and iterating.

Permalink Reply by Ángel Linares on August 8, 2012 at 3:57pm

I've tried that methods...and the results are more like field lines (I suppose that David made it to solve field lines drawing). Try using then...I have try and the results are no the same (particles never return when energy is lost). Perhaps I need to try it harder :P

X.solvestep gives you a vector...not very usefull.

X.solvesteps gives you a point (but moving that points didn't look like particles in a field...perhaps I need more time to see how this works)

I'm rendering some images now. When finished I'll uoload the file with the euler solver configured instead the iterative one.

In the other hand, I have to revise the code because the vector addition have some "conceptual" problems.

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