I'm trying to merge some coincident nodes, but FEMAP won't do it! I get the message: Node Combination Not Merged to prevent Element corruption. I cannot see how this merging would corrupt any of those elements with coincident nodes. The nodes have equal coordinates.
Check the Output Coordinate Systems assigned to the nodes, FEMAP will not merge nodes that have different Output Coordinate Systems. Do List -> Model -> Nodes and list the nodes in question and check their Output CSys's. You need to make them consistent to Merge, so use Modify - Update Other - Output Coordinate System and set them all to be the same.
Be careful if any loads or constraints were defined using these Coordinate Systems, this could change your model! This is why we don't automatically merge them.