Autodesk Certified Professional in AutoCAD for Design and Drafting Practice Exam

Which of the following are valid clipping objects when clipping a viewport?

1. A circle and a line

2. An arc and an open polyline

3. An ellipse and a closed polyline

4. A rectangle and a text object

The correct answer is: An ellipse and a closed polyline

When clipping a viewport in AutoCAD, the valid clipping objects must be shapes that can define a boundary for the viewport. A closed polyline is a valid option, as it creates a complete enclosure that can be used to restrict the view of the objects within the viewport. In this context, an ellipse can also be used as a clipping boundary since it represents a closed shape that can define a curved area in the viewport. Together, these two objects form a valid clipping boundary. Other combinations, such as a rectangle with a text object or a circle with a line, do not form valid clipping boundaries for viewports since they either lack closure or have components that cannot define a limit to a viewport's visible drawing area. The use of an arc with an open polyline is also not valid because an open polyline does not complete a boundary necessary for effective clipping. Therefore, the combination of an ellipse and a closed polyline stands out as the valid choice for creating a clipping object in AutoCAD viewports.