Create new loft form

[AndrewButenko]

Hello!

I try use new loft form with 

fdoc.FamilyCreate.NewLoftForm(True, ref_ar_ar)

In the ref_ar_ar I add two array(Bottom and Top) of ReferencePoint. 

But I get form like a screenshot: 

 

I want get red line, but revit create line like a "wave".

Help me pleaase.

[jeremytammik]

Dear Andrew,

It is very hard to say anything at all based only on the screen snapshot you share.

Maybe you should share the relevant code snippet as well, or, better still, a full reproducible case.

Here are some discussions by The Building Coder on making use of NewLoftForm:

• Revit Form Creation API -- http://thebuildingcoder.typepad.com/blog/2009/07/revit-form-creation-api.html
• On Creating a Mass from 3D Points -- http://thebuildingcoder.typepad.com/blog/2012/03/on-creating-a-mass-from-3d-points.html
• DirectShape Topics -- http://thebuildingcoder.typepad.com/blog/2018/01/directshape-topics-and-happy-new-year.html

Cheers,

Jeremy

[AndrewButenko]

Hi Jeremy!

I create loft using next code: 

   Private Function CreateLoftForm(document As Autodesk.Revit.DB.Document) As Form
        Dim loftForm As Form = Nothing

        Dim rpa As New ReferencePointArray()
        Dim ref_ar_ar As New ReferenceArrayArray()
        Dim ref_ar As New ReferenceArray()
        Dim rp As ReferencePoint = Nothing
        Dim xyz As XYZ = Nothing


        Dim TransGlobal As Transaction = New Transaction(document)
        TransGlobal.Start("Create loft")




        xyz = document.Application.Create.NewXYZ(85.138522515, 45.303356517, 101.706036745)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)


        xyz = document.Application.Create.NewXYZ(85.383921301, 35.572182287, 101.706036745)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)


        xyz = document.Application.Create.NewXYZ(85.363870218, 35.083519311, 102.034120735)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)


        xyz = document.Application.Create.NewXYZ(84.757225743, 28.25298673, 102.034120735)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)


        xyz = document.Application.Create.NewXYZ(84.689869322, 27.761501607, 102.362204724)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)


        xyz = document.Application.Create.NewXYZ(83.219675545, 20.111233411, 102.362204724)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)


        xyz = document.Application.Create.NewXYZ(83.126540038, 19.735242886, 102.690288714)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)




        Dim cbp As CurveByPoints = document.FamilyCreate.NewCurveByPoints(rpa)
        ref_ar.Append(cbp.GeometryCurve.Reference)
        ref_ar_ar.Append(ref_ar)
        rpa.Clear()
        ref_ar = New ReferenceArray()


        xyz = document.Application.Create.NewXYZ(85.138522515, 45.303356517, 114.829397126)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)

        xyz = document.Application.Create.NewXYZ(85.383921301, 35.572182287, 115.157481116)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)

        xyz = document.Application.Create.NewXYZ(85.363870218, 35.083519311, 115.157481116)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)

        xyz = document.Application.Create.NewXYZ(84.757225743, 28.25298673, 115.485565105)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)

        xyz = document.Application.Create.NewXYZ(84.689869322, 27.761501607, 115.485565105)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)

        xyz = document.Application.Create.NewXYZ(83.219675545, 20.111233411, 115.813649095)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)

        xyz = document.Application.Create.NewXYZ(83.126540038, 19.735242886, 115.813649095)
        rp = document.FamilyCreate.NewReferencePoint(xyz)
        rpa.Append(rp)

        cbp = document.FamilyCreate.NewCurveByPoints(rpa)
        ref_ar.Append(cbp.GeometryCurve.Reference)
        ref_ar_ar.Append(ref_ar)
        rpa.Clear()
        ref_ar = New ReferenceArray()



        loftForm = document.FamilyCreate.NewLoftForm(True, ref_ar_ar)
        TransGlobal.Commit()
        Return loftForm
    End Function

As a result, I get:

I would like, that points would be connected not by "waves", but by lines. Is it possible?

[jeremytammik]

Dear Andrew,

I am sure it is possible.

Please solve this manually through the user interface first, then analyse the result with RevitLookup to see what kind of shape you really require..

Maybe you do not need a loft form but some other shape?

About Revit forms:

http://help.autodesk.com/view/RVT/2019/ENU/?guid=GUID-2B3F71CB-4274-457A-BF31-49280B3B0913

Afaict, a loft has smooth curves between the profiles:

• https://en.wikipedia.org/wiki/Loft_(3D)
• https://en.wikipedia.org/wiki/Lofting

If you want linear curves instead of non-linear ones, you should probably use a different shape.

Cheers,

Jeremy

[jeremytammik]

... Also, if you just need straight edges, a direct shape may be easier and more effective to generate:

http://thebuildingcoder.typepad.com/blog/2018/01/directshape-topics-and-happy-new-year.html/#3

Do you have a reason to prefer a loft form?

Parametrics, for instance?

Cheers,

Jeremy