获取墙的一个侧面，并且将上的点坐标转换到XOY面在墙侧面上的坐标系 - EaBIM

一个客户问在Revit 2011上如何获得一个墙的侧面，而且把侧面坐标转到XOY平面在墙面上的坐标系。对于同一个墙（长宽高相同），任意旋转墙至不同的角度，获取的坐标值是相同的。

我的一篇博客也提到Revit 2012 提供的HostObjUtils类的方法，可以用HostObjUtils.GetSideFaces() 来快速获取侧面。

Revit 2011 没有提供HostObjUtils 类，所以只能是逐个遍历墙上的几何体，面，线。这个方法在2012，2013仍然适用，不过需要写更多的代码。

下面是完整的一个例子获取选定的墙的侧面，并且获取这个面上的Edge的在XOY是墙面的坐标系下的向量。另一个看点是如何做坐标转换，演示了如何使用Transform类。

[vb] view plaincopy
Imports Autodesk.Revit.DB
Imports Autodesk.Revit.UI
Imports Autodesk.Revit.Attributes
Imports Autodesk.Revit.ApplicationServices
Imports Autodesk.Revit.UI.Selection
<TransactionAttribute(Autodesk.Revit.Attributes.TransactionMode.Manual)>
Public Class CommandName
Implements IExternalCommand
Public Function Execute(ByVal commandData As ExternalCommandData, ByRef message As String, ByVal elements As ElementSet) As Result Implements IExternalCommand.Execute
Dim doc As Document
doc = commandData.Application.ActiveUIDocument.Document
'Pick a wall
Dim sel As Selection = commandData.Application.ActiveUIDocument.Selection
Dim ref1 As Reference = sel.PickObject(ObjectType.Element, "Please pick a wall to get its side face")
Dim wall As Wall = ref1.Element
Dim opt As Options = New Options()
opt.View = doc.ActiveView
Dim obj As GeometryObject
Dim solid As Solid
Dim face As Face
Dim planF As PlanarFace
Dim wallDirection As XYZ
Dim LocationCurve As LocationCurve = wall.Location
Dim line As Line = TryCast(LocationCurve.Curve, Line)
If (line Is Nothing) Then
Return Result.Failed
End If
wallDirection = line.EndPoint(0) - line.EndPoint(1)
Dim sideFace As PlanarFace
Dim transf As Transform
'Form a transform, to translate it to the face to the XOY.
transf = Transform.Identity
transf.BasisX = wallDirection.Normalize()
transf.BasisY = wall.Orientation.Normalize()
transf.BasisZ = transf.BasisX.CrossProduct(transf.BasisY)
Dim ptResult1 As XYZ
Dim ptResult2 As XYZ
Dim pt As XYZ
Dim ptString As String = Nothing
For Each obj In wall.Geometry(opt).Objects
If (TypeOf (obj) Is Solid) Then
solid = TryCast(obj, Solid)
'Go through each face
For Each face In solid.Faces
planF = TryCast(face, PlanarFace)
If (Not (planF Is Nothing)) Then
If (planF.Normal.DotProduct(wallDirection) < 0.0001 And Math.Sin(planF.Normal.AngleTo(wall.Orientation)) < 0.001) Then
'get the side face.
sideFace = planF
transf.Origin = sideFace.Origin
'now you can convert the points in the sdie face to the user coordiantes. the result is like it.
For Each edArr As EdgeArray In sideFace.EdgeLoops
For Each ed As Edge In edArr
pt = ed.Tessellate()(0)
ptResult1 = transf.OfPoint(pt)
pt = ed.Tessellate()(ed.Tessellate().Count - 1)
ptResult2 = transf.OfPoint(pt)
ptString += (ptResult1 - ptResult2).X.ToString() + " ; " + (ptResult1 - ptResult2).Y.ToString() + " ; " + (ptResult1 - ptResult2).Z.ToString() + vbCrLf
Next
Next
End If
End If
Next
End If
Next
TaskDialog.Show("pts", ptString)
Return Result.Succeeded
End Function
End Class

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