CustomTool Pick

[Vincent Ullmann]

Hey List,

currently i try to develop a little CustomTool.
Most of it works fine, except one annoying Issue.
I use the Pick-Command to get a current Location under my Cursor
As demonstrated in the attached picture, when the cursor is near the 
Edge between Object and ViewportBackground there seems to be an Error.

Does anyone know how to avoid this?

in_ctxt.GetMousePosition( cursX, cursY );
CLongArray l_points;    l_points.Add( cursX);   l_points.Add( cursY );
CRefArray pickObjs;

in_ctxt.Pick( l_points, siPickSingleObject, siPickRaycast, L"", CRefArray(), 
pickObjs );                
if( pickObjs.GetCount() != 0 && X3DObject(pickObjs[0]).GetType() == L"polymsh"  
)
{
        // Try to get a Object
        CLine worldRay;
        in_ctxt.GetWorldRay(cursX, cursY, worldRay);
        CVector3   rayO = worldRay.GetOrigin();
        CVector3   rayD = worldRay.GetTangent();
        
        X3DObject pickObj(pickObjs[0]);
        PointLocatorData locs = 
pickObj.GetActivePrimitive().GetGeometry().GetRaycastIntersections(1, 
(double*)&rayO, (double*)&rayD, siSemiLineIntersection );
        pickObj.GetActivePrimitive().GetGeometry().EvaluatePositions(locs, -1, 
0, (double*)&worldPos);                  
}               
else
{
        in_ctxt.GetWorldPosition(       cursX, cursY, worldPos  );
}<<attachment: LocUnderCursor_snap.jpg>>