BRepBuilder Class

A class that allows direct construction of geometry objects (solids, open shells, etc.).
Inheritance Hierarchy
SystemObject
  Autodesk.Revit.DBShapeBuilder
    Autodesk.Revit.DBBRepBuilder

Namespace: Autodesk.Revit.DB
Assembly: RevitAPI (in RevitAPI.dll) Version: 25.0.0.0 (25.0.0.0)
Syntax
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public class BRepBuilder : ShapeBuilder

The BRepBuilder type exposes the following members.

Constructors
 NameDescription
Public methodBRepBuilder Construct a BRepBuilder to use in constructing geometry.
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Properties
 NameDescription
Public propertyIsValidObject Specifies whether the .NET object represents a valid Revit entity.
(Inherited from ShapeBuilder)
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Methods
 NameDescription
Public methodAddCoEdge Add a co-edge associated to a previously added edge. A co-edge represents the use of an edge on one of the edge's faces. BrepBuilder allows at most two faces per edge, hence at most two co-edges per edge, and the co-edges must have opposite bCoEdgeIsReversed flags. The co-edges in a loop must be added in the order in which they occur in the loop (i.e., in their topological order).
Public methodAddEdge Add a new edge to the geometry being built. The BRepBuilder uses edges only to store edge geometry and to track pairs of co-edges that share an edge.
Public methodAddFace Creates an empty face in the geometry being built. Other BRepBuilder methods are used to add loops to the face.
Public methodAddLoop Creates an empty loop in a given face of the geometry being built. Other BRepBuilder methods are used to add co-edges to the loop.
Public methodAllowRemovalOfProblematicFaces Allow BRepBuilder to remove problematic faces (e.g., due to inaccurate edge geometry). If this option is enabled and BRepBuilder removes some faces, the output geometry's type will be OpenShell regardless of the expected type specified when the BRepBuilder was created.
Public methodCanAddGeometry A validator function that checks the state of this BRepBuilder object. Returns true if this BRepBuilder object is accepting b-rep data, false otherwise.
Public methodDispose
(Inherited from ShapeBuilder)
Public methodEqualsDetermines whether the specified object is equal to the current object.
(Inherited from Object)
Public methodFinish Complete construction of the geometry. The geometry will be validated and, if valid, stored in this BRepBuilder. Otherwise it will be deleted.
Public methodFinishFace Indicates that the caller has finished defining the given face.
Public methodFinishLoop Indicates that the caller has finished defining the given loop.
Public methodGetHashCodeServes as the default hash function.
(Inherited from Object)
Public methodGetResult Get the Solid built by this BRepBuilder. This will clear the built geometry stored in the BRepBuilder. This function will throw if this BRepBuilder hasn't completed building the b-rep. Use IsResultAvailable() to verify that this BRepBuilder contains a valid result.
Public methodGetResult(ExternalGeometryId, BRepBuilderPersistentIds) Get the ExternallyTaggedBRep built by this BRepBuilder. This will clear the built geometry stored in the BRepBuilder. This function will throw if this BRepBuilder hasn't completed building the b-rep. Use IsResultAvailable() to verify that this BRepBuilder contains a valid result.
Public methodGetTypeGets the Type of the current instance.
(Inherited from Object)
Public methodStatic memberIsPermittedSurfaceType A validator function that checks whether the surface object is of type supported as face surface by BRepBuilder.
Public methodIsResultAvailable A validator function that checks the state of this BRepBuilder object. Returns true if this BRepBuilder object has successfully built a b-rep.
Public methodIsValidEdgeId A validator function that checks whether the edge id corresponds to an edge previously added to this BRepBuilder object.
Public methodIsValidFaceId A validator function that checks whether the face id corresponds to a face previously added to this BRepBuilder object.
Public methodIsValidLoopId A validator function that checks whether the loop id corresponds to a loop previously added to this BRepBuilder object.
Public methodIsValidPersistentIdsMap A validator function that makes sure that all BRepBuilderGeometryIds in the input map can be found in this BRepBuilder object.
Public methodRemovedSomeFaces Returns 'true' if BRepBuilder removed some problematic faces from the output geometry, 'false' if not. If allowRemovalOfProblematicFaces was not called to enable removal of problematic faces, this function will return 'false'. Note that if some faces were removed, the output geometry's type will be OpenShell regardless of the expected type that was specified when the BRepBuilder was created.
Public methodSetAllowShortEdges Make BRepBuilder allow edges that it would normally disallow as being too short for Revit geometry.
Public methodSetFaceMaterialId Sets material id to a face.
Public methodToStringReturns a string that represents the current object.
(Inherited from Object)
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Example
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private void CreateDirectShapeFromCylinder(Document doc)
{
    // Naming convention for faces and edges: we assume that x is to the left and pointing down, y is horizontal and pointing to the right, z is up
    BRepBuilder brepBuilder = new BRepBuilder(BRepType.Solid);

    // The surfaces of the four faces.
    Frame basis = new Frame(new XYZ(50, -100, 0), new XYZ(0, 1, 0), new XYZ(-1, 0, 0), new XYZ(0, 0, 1));
    CylindricalSurface cylSurf = CylindricalSurface.Create(basis, 50);
    Plane top = Plane.CreateByNormalAndOrigin(new XYZ(0, 0, 1), new XYZ(0, 0, 100));  // normal points outside the cylinder
    Plane bottom = Plane.CreateByNormalAndOrigin(new XYZ(0, 0, 1), new XYZ(0, 0, 0)); // normal points inside the cylinder

    // Add the four faces
    BRepBuilderGeometryId frontCylFaceId = brepBuilder.AddFace(BRepBuilderSurfaceGeometry.Create(cylSurf, null), false);
    BRepBuilderGeometryId backCylFaceId = brepBuilder.AddFace(BRepBuilderSurfaceGeometry.Create(cylSurf, null), false);
    BRepBuilderGeometryId topFaceId = brepBuilder.AddFace(BRepBuilderSurfaceGeometry.Create(top, null), false);
    BRepBuilderGeometryId bottomFaceId = brepBuilder.AddFace(BRepBuilderSurfaceGeometry.Create(bottom, null), true);

    // Geometry for the four semi-circular edges and two vertical linear edges
    BRepBuilderEdgeGeometry frontEdgeBottom = BRepBuilderEdgeGeometry.Create(Arc.Create(new XYZ(0, -100, 0), new XYZ(100, -100, 0), new XYZ(50, -50, 0)));
    BRepBuilderEdgeGeometry backEdgeBottom = BRepBuilderEdgeGeometry.Create(Arc.Create(new XYZ(100, -100, 0), new XYZ(0, -100, 0), new XYZ(50, -150, 0)));

    BRepBuilderEdgeGeometry frontEdgeTop = BRepBuilderEdgeGeometry.Create(Arc.Create(new XYZ(0, -100, 100), new XYZ(100, -100, 100), new XYZ(50, -50, 100)));
    BRepBuilderEdgeGeometry backEdgeTop = BRepBuilderEdgeGeometry.Create(Arc.Create(new XYZ(0, -100, 100), new XYZ(100, -100, 100), new XYZ(50, -150, 100)));

    BRepBuilderEdgeGeometry linearEdgeFront = BRepBuilderEdgeGeometry.Create(new XYZ(100, -100, 0), new XYZ(100, -100, 100));
    BRepBuilderEdgeGeometry linearEdgeBack = BRepBuilderEdgeGeometry.Create(new XYZ(0, -100, 0), new XYZ(0, -100, 100));

    // Add the six edges
    BRepBuilderGeometryId frontEdgeBottomId = brepBuilder.AddEdge(frontEdgeBottom);
    BRepBuilderGeometryId frontEdgeTopId = brepBuilder.AddEdge(frontEdgeTop);
    BRepBuilderGeometryId linearEdgeFrontId = brepBuilder.AddEdge(linearEdgeFront);
    BRepBuilderGeometryId linearEdgeBackId = brepBuilder.AddEdge(linearEdgeBack);
    BRepBuilderGeometryId backEdgeBottomId = brepBuilder.AddEdge(backEdgeBottom);
    BRepBuilderGeometryId backEdgeTopId = brepBuilder.AddEdge(backEdgeTop);

    // Loops of the four faces
    BRepBuilderGeometryId loopId_Top = brepBuilder.AddLoop(topFaceId);
    BRepBuilderGeometryId loopId_Bottom = brepBuilder.AddLoop(bottomFaceId);
    BRepBuilderGeometryId loopId_Front = brepBuilder.AddLoop(frontCylFaceId);
    BRepBuilderGeometryId loopId_Back = brepBuilder.AddLoop(backCylFaceId);

    // Add coedges for the loop of the front face
    brepBuilder.AddCoEdge(loopId_Front, linearEdgeBackId, false);
    brepBuilder.AddCoEdge(loopId_Front, frontEdgeTopId, false);
    brepBuilder.AddCoEdge(loopId_Front, linearEdgeFrontId, true);
    brepBuilder.AddCoEdge(loopId_Front, frontEdgeBottomId, true);
    brepBuilder.FinishLoop(loopId_Front);
    brepBuilder.FinishFace(frontCylFaceId);

    // Add coedges for the loop of the back face
    brepBuilder.AddCoEdge(loopId_Back, linearEdgeBackId, true);
    brepBuilder.AddCoEdge(loopId_Back, backEdgeBottomId, true);
    brepBuilder.AddCoEdge(loopId_Back, linearEdgeFrontId, false);
    brepBuilder.AddCoEdge(loopId_Back, backEdgeTopId, true);
    brepBuilder.FinishLoop(loopId_Back);
    brepBuilder.FinishFace(backCylFaceId);

    // Add coedges for the loop of the top face
    brepBuilder.AddCoEdge(loopId_Top, backEdgeTopId, false);
    brepBuilder.AddCoEdge(loopId_Top, frontEdgeTopId, true);
    brepBuilder.FinishLoop(loopId_Top);
    brepBuilder.FinishFace(topFaceId);

    // Add coedges for the loop of the bottom face
    brepBuilder.AddCoEdge(loopId_Bottom, frontEdgeBottomId, false);
    brepBuilder.AddCoEdge(loopId_Bottom, backEdgeBottomId, false);
    brepBuilder.FinishLoop(loopId_Bottom);
    brepBuilder.FinishFace(bottomFaceId);

    brepBuilder.Finish();

    using (Transaction tr = new Transaction(doc, "Create a DirectShape"))
    {
        tr.Start();
        DirectShape ds = DirectShape.CreateElement(doc, new ElementId(BuiltInCategory.OST_GenericModel));
        ds.SetShape(brepBuilder);
        tr.Commit();
    }
}
See Also