The Fit Cylinder functionality now has a new mode which works allows user to extract cylinder by only clicking a point of the point cloud modeling the cylinder to extract.
The One Click Mode works by following the points pertaining to the cylinder from both direction from the point clicked until the end of the cylinder is encounter (for example when an elbow or a pressure vessel is encounter) or until there is not enough points to continue (for example if part of the cylinder is occluded).
Here is a short video showing how easy it is to extract cylinder of various diameter just by one click :
Functional Tip : Note that the one click mode tool works only when a point is clicked (i.e. : you need to snap on a point of the point cloud in order to extract cylinder.
Performance Tip : For minimizing extraction failure choose a point which is near a part of the cylinder represented by a lot of point cloud's points and is as far as possible as other component(s) connecting to the cylinder to extract, if any.
The Maximum RMS Error setting can have an important impact on the precision extracted. The maximum RMS error is related to the distance of the points from the extracted cylinder. During the fit cylinder operation the points whose distance is less than the maximum distance between the point and the surface of the potential cylinder model are deemed pertaining to the cylinder, and thus used during the modelling of the cylinder.
The video below shows how the Maximum RMS Error can affect the precision of the extracted cylinder.
http://communities.bentley.com/cfs-file.ashx/__key/CommunityServer-Components-PostAttachments/00-00-26-82-19/FitCylinderONeClickRMSError.wmv
Performance Tip : There is a compromised to be made when setting the Maximum RMS Error. A big value will optimize the chance of finding a cylinder, at the cost of less precision, while a small value will optimize the precision of the cylinder extracted, at the higher failure rate.