Skeletonization occurs on only active topology but considers all topology. That is, any inactive topology of a model is unable to be skeletonized but is not outright ignored for skeletonization purposes. This fact can be used to perform spatial skeletonization. For example, if you only wish to skeletonize a portion of your model, you can temporarily deactivate the topology you wish to be immune to skeletonization, remembering of course, to reactivate it after you have completed the skeletonization process. Any points where inactive topology ties in to the active topology will not be compromised. To better explain this, consider two series pipes that are not merged by series pipe removal. Under most circumstances two series pipes that meet the following conditions will be skeletonized:

The two series pipes still may not be skeletonized if any inactive topology could be affected by the execution of the skeletonization action. For example, if the two series pipes have an additional but inactive pipe connected to their common node, and if the series pipe removal action was allowed to proceed, the common node would be removed from the model, and the inactive topology would become invalid. This is prevented from occurring in Skelebrator.