Collision free path planning for Coordinate Measuring Machines (CMMs) is an important task in automatic inspection planning. The goal is to generate an efficient and collision-free path between two adjacent points in the inspection sequence. Two interference detection methods based on swept volumes are discussed. The first method extrudes the silhouette boundary of the probe as a 2D profile to create a swept volume then performs a Boolean intersection; the second method exploits raster graphics hardware to provide efficient interference computation in image space using the depth buffer. A heuristic collision avoidance algorithm is then employed to make a detour around the interference volume. The effectiveness of the methods is verified by experiments to demonstrate collision-free path generation for parts with complex geometry.