We seem to have a problem with Arc10 with some CAD drawings - this problem did not occur on Arc 9.3.1 or any other earlier versions - we've actually tested the same CAD drawings on different Arc versions.
When using the polyline (or polygon) feature class from CADs (DWG) the arc segment at the end of a CAD polyline feature appears as a line pointing towards the CAD drawing's origin (i.e. X=0, Y=0). The problem always involves a curved section at the end of the polyline feature and never a curved section in the middle of a polyline... If we export the CAD polyline/polygon to shape files/geodatabase feature classes the lines translate as parts of the whole feature - and to get rid of them - we need to actually split each individual line separately and then delete the "imaginary" line part and then re-draw the arc segment that they were intended to show - which is extremely time-consuming. In pre-Arc10 versions these "imaginary" lines are not visible - nor do they get exported to shape files/geodatabase feature classes as parts of features.
The problem can perhaps best be described visually - I've attached 2 screen prints, one of the polyline feature class viewed in ArcCatalog 9.2 (looking/behaving as it should) and one of the polyline feature class in ArcCatalog 10 showing the said lines pointing towards the CAD drawing's origin. The effect is quite "striking"...
Anyone out there with a similar problem - urgent help needed 🙂