brep vs. mesh

Replies to This Discussion

Permalink Reply by Fan Zhang on March 20, 2011 at 8:18pm

Btw, this is what I have tried:

 

Private Sub RunScript(ByVal outerhex As List(Of Curve), ByVal innerhex As List(Of Curve), ByRef units As Object)
    'your code goes here…

    Dim num As int32 = outerhex.Count()
    Dim i As int32
    Dim surface_list As New List(Of mesh)
    For i = 0 To num - 1

      Dim outercurve As Curve = outerhex(i)
      Dim innercurve As Curve = innerhex(i)
      Dim curves As New list(Of Curve)
      curves.add(outercurve)
      curves.add(innercurve)

      Dim startpt As point3d = outercurve.PointAtEnd
      Dim endpt As point3d = innercurve.PointAtEnd

      Dim surface_array() As brep = rhino.Geometry.Brep.CreateFromLoft(curves, startpt, endpt, LoftType.Straight, False)

      Dim newbrep As brep = surface_array(0).DuplicateBrep
      Dim newmesh As mesh
      newmesh = mesh.CreateFromBrep(newbrep)



      surface_list.Add(newmesh)

    Next

    units = surface_list

  End Sub

 

 

 

 

The error message is:

 

Error: Value of type '1-dimensional array of Rhino.Geometry.Mesh' cannot be converted to 'Rhino.Geometry.Mesh'

Permalink Reply by David Rutten on March 21, 2011 at 1:49am

When you mesh a Brep, you actually get an array of meshes. So this:

 

newmesh = mesh.CreateFromBrep(newbrep)

 

is illegal. You cannot assign an array of Meshes to a single Mesh. Try the following:

 

Private Sub RunScript(ByVal outerhex As List(Of Curve), _

                               ByVal innerhex As List(Of Curve), _

                               ByRef units As Object) 

    
  Dim meshes As New List(Of Mesh)
  For i As Int32 = 0 To outerhex.Count - 1
    Dim curves As New List(Of Curve)
    curves.Add(outerhex(i))
    curves.Add(innerhex(i))

    Dim loft() As Brep = Brep.CreateFromLoft(curves, Point3d.Unset, Point3d.Unset, LoftType.Straight, False)

    If (loft Is Nothing) Then Continue For

    If (loft.Length = 0) Then Continue For

    Dim loftMeshes As Mesh() = Mesh.CreateFromBrep(loft(0))
    If (loftMeshes Is Nothing) Then Continue For

    If (loftMeshes.Length = 0) Then Continue For

    'Now merge all partial meshes into a single mesh

    Dim loftMesh As New Mesh

    For Each partialMesh As Mesh in loftMeshes

      loftMesh.Append(partialMesh)

    Next

    meshes.Add(loftMesh)
  Next

  units = meshes
End Sub

 

--

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by David Rutten on March 21, 2011 at 1:51am

Typically meshes take less memory than breps, especially since breps use a secondary mesh to draw themselves in shaded modes. Though if you switch to wireframe preview this won't happen.

 

If memory is really a problem, and if you have a 64-bit OS, you can try Rhino5 64-bit. It can handle enormous files.

 

--

David Rutten

david@mcneel.com

Poprad, Slovakia

 

Permalink Reply by Fan Zhang on March 21, 2011 at 10:06am

WOW, it is hundreds of times faster now! Thanks so much David, You are amazing!!!

 

For the same project, I have another question. Right now the loft gives me a surface without thickness. If I want to make it into hexes with thickness, would I need to extrude each of the six surface, trim them and join? Or is there any better way to do this?

 

Thanks again for your help!