How do I find if a line intersects a closed line (polygon)?

[Andreas_W_Paulsen]

I have one closed Polyline: "rectangle" and an open Polyline: "line".
Both Polylines may be Z aware.
What is the best way to find if the "line" intersects the "rectangle" in the XY plane?
That is I want a 2D (XY) test for intersection. I do not need the actual coordinates of any intersection(s).

[LeoDonahue]

ITopologicalOperator

[Andreas_W_Paulsen]

ITopologicalOperator

Call the Intersect method with esriGeometry0Dimension?
Does this take care of the 2D part of the intersection or do I have to strip away any z information first by copying the x and y value of the points?

[LeoDonahue]

From the docs:

If the Geometry includes z or m values, the z or m domains, z or m resolutions,  and z or m cluster tolerance properties must also be defined. The cluster  tolerance and resolutions can be quickly and easily set using SetDefault methods  on ISpatialReferenceResolution and ISpatialReferenceTolerance interfaces.

[WeifengHe]

If you do not need the actual coordinates of any intersection(s) as you said, you can also use IRelationalOperator methods to test the spatial relation between geometries.