Surprising results from Face.Intersect(face) method

[ciganek]

This has been mentioned in this post from 2016 but maybe it's worth bringing up again as 2018 hasn't resolved the issue yet.

As far as I can tell, the Face.Intersect(face) method always returns FaceIntersectionFaceResult.Intersecting - or I am not implementing it correctly. When I run the code below in a view with a single wall and single floor, each face to face test returns an intersection. Can someone please verify (maybe 2019)?

public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
{

var list = new FilteredElementCollector(commandData.Application.ActiveUIDocument.Document, commandData.View.Id).WhereElementIsNotElementType().Where(e => e is Wall || e is Floor);

foreach (var f1 in list.First().get_Geometry(new Options()).OfType<Solid>().First().Faces.OfType<Face>())
{
foreach (var f2 in list.Last().get_Geometry(new Options()).OfType<Solid>().First().Faces.OfType<Face>())
{
if (f1.Intersect(f2) == FaceIntersectionFaceResult.Intersecting)
{

if (System.Windows.Forms.MessageBox.Show("Intersects", "Continue", System.Windows.Forms.MessageBoxButtons.OKCancel, System.Windows.Forms.MessageBoxIcon.Exclamation) == System.Windows.Forms.DialogResult.Cancel) return Result.Succeeded;
}
}
}

return Result.Succeeded;
}

[ankofl]

Hi @ciganek 

You can try this code (GitHub CustomCSG) . It finds the intersection of two PlanarFace lying in the same plane and returns a List<PlanarFace>

PlanarFace planarOne = null; // select your first PlanarFace
PlanarFace planarTwo = null; // select your second PlanarFace

List<PlanarFace> booleanPlanarFaces = planarOne.ExecuteBooleanOperation(planarTwo, BooleanOperationsType.Intersect);

Result of running CustomCSG.dll.CommandCaller by AddinManager in sample project ProjectToView.rvt