The previous version has wrongly convert position from 3ds coordinate system to WPF coordinate system. The difference is that the X axis now points to the right instead of the left and the Z axis points to the viewer and not away from it. This version by default uses new coordinate system, but if your application depends on the old one, you can simple set this property to true. But note that this can only be a temporary solution.

[ObsoleteAttribute("This property is valid only for backward compatibility and will be removed after version 4.2")]
public bool UseOldCoordinateAxis { get; set; }