[AeroCat]

Figured I could do a search and find the answer to this, but I didn't.

I'm trying to join two connectors to eliminate extraneous nodes and I have a couple of instances where I can't join two connectors. I have made sure that where they meet does not need to be merged and they share a common node. When I click on join, it just tells me that no connectors were joined.

What would keep me from being able to join connectors?

[AeroCat]

Just watched the Meshing Forensics webinar and Carolyn said that there are three reasons that you might not be able to connect two connectors:

1. Nodes need merged
2. It will destroy topology (If you have three connectors sharing a node for example)
3. If you have duplicate connectors on one side or the other

Are there any other causes?
Can I tell how many connectors utilize a node?

[cnsidero]

Yes, there is at least one more instance (that I can think of). You can't join the first and last connectors of an unstructured domain's edge. A visual might help.

I created a domain with a hole in the middle. See 1st image. Notice the internal edge begins-ends at the node on the right.

Now I decide I want to join the four hole connectors into two - one on the left and one on the right. The pair on the left will join but the not the right pair because the beginning-ending of the internal edge is at their common node location. See 2nd image.

In this case the work around is join the connectors first then add them to the edge. For an existing domain remove the edge with Edit>Add/Remove Edges, join the connectors, then re-add the edge with Edit>Add/Remove Edges.