Rhino.Geometry.Brep.IsPointInside() shows opposite bool result

[AYuA]

When I use Rhino.Geometry.Brep.IsPointInside() with the Brep made by Rhino.Geometry.Brep.CreateOffsetBrep(), it shows the different result from the normal one.

Is this bug? or I am missing something?

I will upload GH file.

IsPointInside.gh (14.7 KB)

[AYuA]

This also shows oppposite result…

IsPointInside.gh (12.9 KB)

[eirannejad (Ehsan Iran-Nejad)]

Are you expecting a point of {0, 0, 20} to be inside a box of 10x10x10 extruded from a point at Z of -10? The top of the box is at Z==10

[AYuA]

Yes !! it just tow boxes I made are the same. but when do [IsPointInside(), the result become inverse. i was wondering why.

[AYuA]

Sorry now I understand.
The brep extrudes from a surface has a inversed normals.
its a default behavior ?