I have built 7 identical tubes and placed them at the correct geometrical coordinates. Now I want to connect these tubes with rigid connections (or other types of connection, problem remains the same).

I looked for a 'CONNECT' function but could only find the CLOSE LOOP function. And I don't understand how it works.

This is what I do:

I have 6 tubes, tube 1 is nodes 5010-5060, tube 2 is nodes 5110-5160, tube 3 is nodes 5210-5260, etc
Each tube is at its correct absolute coordinates positioned in space.
I try to set up a new connection between for instance node 5020 (tube 1) and 5120 (tube 2).
I enter the node numbers 5020 and 5120 and click on CLOSE LOOP. I am now asked for new global coordinates for node 5110 (???), which I just don't understand. Entering or canceling now messes up my model.

What do I do wrong, or (better) how do I connect two existing nodes without changing their absolute coordinates?
I tried several other things like creating a new section and then changing node numbers but that messes up my model too.

I just can't believe this isn't possible, so what am I overlooking?

Any help strongly appreciated right now!

“Include piping files” command in the environment menu is the proper command. Browse, select the file and open the required file. Then click on the file in the highlighted list. Now change the N to Y below the read now option as required. Say the individual files are created and saved. The co ordinate option is for entering the co ordinate of the first node of each file. With this the position of the first node in the space is fixed. Otherwise the starting node has 0,0,0 as the co ordinate.
Another method if you want to attach one file with another file, make the node number same in both the files for ONLY the joining nodes. Without giving the co ordinate values these files will be joined. All the other nodes should have different numbers.

Shiny Mathew: thanks for taking time and effort to answer my question. But the problem I was dealing with is not related to different files but to different parts in the same file. And the parts I want to connect to do not have nodes at the same coordinates. So I really want (and have to) enter a new section, connecting two existing nodes.

My workaround I found myself was making a new routing of rigids with nodes coinciding with the nodes where I want to make the connection.
Then, using the CNODE option of RESTRAINTS, couple the nodes of the tubes with the rigids.

This seems to work. However, it introduces (in my case) a lot of extra nodes with additional administration (and chance on errors). And these extra nodes are hard to see since they have the same coordinates as the node they are coupled with.

Meanwhile I got an alternative solution from a support engineer I will post separately.

I received this reply from a support engineer (and I got it quick!):

"My suggestion to the user is to first find a distance between the nodes where the rigid elements will go. Then use the insert button to insert an element (put a check in Rigid selection box) from lets say 5010 to 5020 specifying its length as determined using the distance tool. This way a rigid element will be inserted between 5010 and 5020 nodes."

I tried the method described above and it indeed leads to a new connection using two existing nodes. So far so good.

But I would suggest to COADE to reconsider this situation and introduce a new 'CONNECT' function which connects two existing nodes without having to calculate or enter the distance between the nodes (and use their original position). The function for retrieving coordinates and calculate distance between 2 given nodes is already available in CAESAR, it is just a matter of transferring these data to the input fields.

Unless I'm misunderstanding this description, this is what "close loop" does. I really don't like this function because if you have a geometry error in the model, "close loop" will blindly determine what length is necessary to connect the two (specified) nodes and put that in the delta fields. This is rather like putting a band-aid over a pot hole.

Not completely. Close Loop works that way in a model with only one (connected) piping part. I had 7 not connected parts in my model. That's the situation where I could not use Close Loop and had to set manually the dimensions to get things right.