Seperating AutoCAD surfaces with two seperate entities in one object

sbouwens — Thu, 11 Aug 2022 12:13:33 GMT

Hello,

I'm currently working on a .net project related to slicing surfaces based on several boundaries. However, i've encountered a problem with this challenge. The problem occurs when a autocad surface is sliced in the middle, and a new surface with two or more seperate bodies is created, as seen in the image below. Slicing this outside surface then results in an eNoIntersections error. Hence, it is needed to seperate the outside surface into two seperate entities . Then only the surface that intersects with the boundary can be selected an no error should occur.

The code snippet (VB.NET) that currently performs the task of slicing the surface is attached below:

Dim surfaceInsideBounds = DirectCast(sliceObject, Autodesk.AutoCAD.DatabaseServices.Surface) Dim sliceResults As SurfaceSliceResults = surfaceInsideBounds.SliceBySurface(SweptSurface) Dim surfaceOutsideBounds As Autodesk.AutoCAD.DatabaseServices.Surface = sliceResults.NegativeHalfSurface surfaceOutsideBounds.SetDatabaseDefaults() surfaceOutsideBounds.Layer = sliceObject.Layer surfaceOutsideBounds.Color = sliceObject.Color btr.AppendEntity(surfaceOutsideBounds) trans2.AddNewlyCreatedDBObject(surfaceOutsideBounds, True)

The surface inside the boundary and outside the boundary needs to be preserved in this process.

I'm looking for a similar method as described in Separate Solid Complexes into Separate Solids - AutoCAD DevBlog

with solid.SeparateBody(), but then for AutoCAD Surfaces. Can anyone provide some help?

With kind regards,

Stan Bouwens

Re: Seperating AutoCAD surfaces with two seperate entities in one object

sbouwens — Wed, 24 Aug 2022 09:17:24 GMT

I'm currently stuck with the idea of exploding the surface with seperate bodies, and then unioning the parts that intersect with each other. Somewhere between lines 20-31 it somehow goes wrong.

For Each oid In userSelectionIds Dim surfaceToSplit As Autodesk.AutoCAD.DatabaseServices.Surface = TryCast(acTrans.GetObject(oid, OpenMode.ForWrite), Autodesk.AutoCAD.DatabaseServices.Surface) Dim surfDBOBJColl As New DBObjectCollection Using acDBObjColl As New DBObjectCollection() surfaceToSplit.Explode(acDBObjColl) For Each DBObject In acDBObjColl If DBObject.GetType() = GetType(Autodesk.AutoCAD.DatabaseServices.Surface) Then surfDBOBJColl.Add(DirectCast(DBObject, Autodesk.AutoCAD.DatabaseServices.Surface)) ElseIf DBObject.GetType() = GetType(Autodesk.AutoCAD.DatabaseServices.Region) Then Dim surface As New Autodesk.AutoCAD.DatabaseServices.Surface() surface.SetDatabaseDefaults() surface = Autodesk.AutoCAD.DatabaseServices.Surface.CreateFrom(DirectCast(DBObject, Autodesk.AutoCAD.DatabaseServices.Region)) surfDBOBJColl.Add(surface) Else ed.WriteMessage(vbLf & "Exploded entity is not a Surface or a Region") End If Next End Using For Each motherSurface In surfDBOBJColl ResetJoin: For Each toJoinSurface In surfDBOBJColl If toJoinSurface = motherSurface Then Continue For Dim intersectEntity As Entity() = motherSurface.BooleanIntersect(toJoinSurface) If intersectEntity IsNot Nothing Then motherSurface.BooleanUnion(toJoinSurface) surfDBOBJColl.Remove(toJoinSurface) GoTo ResetJoin End If Next Next For Each joinedSurface In surfDBOBJColl joinedSurface.Layer = surfaceToSplit.Layer joinedSurface.Color = surfaceToSplit.Color btr.AppendEntity(joinedSurface) acTrans.AddNewlyCreatedDBObject(joinedSurface, True) Next surfaceToSplit.Erase() Next acTrans.Commit()

Can anyone provide me some guidance on joining surfaces together that overlap?

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Seperating AutoCAD surfaces with two seperate entities in one object

Re: Seperating AutoCAD surfaces with two seperate entities in one object