I REALLY Need Some Help With Understanding the UCS and Custom Connections
Hi Dave,
Thank you for posting your request here.
You might find useful this dedicated class presented at Autodesk University:
You will find the video, the handout and the additional materials there.
I hope it will help you.
Best regards,
Emy
Emy Nestor
Many thanks for taking the time to respond Emy it is much appreciated however, the documentation does not really discuss the UCS other than in the third example where it says that it needs to be moved to the posts system line - after doing this I note that the orientation of my UCS is different to that which is in the documentation and if I further try to draw a polyline as requested it does not start at the system post line where I placed the UCS rather it starts at where the original UCS was before I moved it.
All very confusing stuff.
I only want to be able to have an item, a right angle bracket that can be in either 12 o'clock, 3 o'clock, 6 o'clock or 9 o'clock positions.
I started with the bracket in the 6 o'clock position and this seems to work with no problems.
However, either drawing the 12 o'clock position from scratch or mirroring the 6 o'clock or rotating the 6 o'clock I always end up with the bracket upside down and back to front when placing as a new connection.
I appreciate items have their own internal UCS that can be altered however, I do not understand what's behind this and I believe that I can only draw my wireframes without using mirror\rotate commands as these somehow interfere with generated sections and connections.
I find I need to draw my wireframes from new and apply sections in specific view directions so as not to have to alter the sections position.
I also have an anomaly with the UCS\origin when changing certain views see the following screenshots:
Top View showing Z axis coming out the screen
Then go to South East view with Z axis going up the screen as expected
Now a FRONT view showing the Z axis either coming out the screen or going away from the screen, either way it's not what I expected
And now back to a SE view showing the Z axis in a different orientation from the SE Z axis two pictures above again, not what I expected.
I am finding it impossible to keep track of these changes without any rules to understand why it won't do what I want it to or expect.
I appreciate that it is my stupidity that is stopping me from getting this hence my request for a link to a detailed tutorial that explains these anomalies and not only how to change the UCS but why it is being changed?
Muleman,
Thanks for your input, I do appreciate that I have to create separate joints relative to their orientation.
In this instance I am trying to create a joint between two C sections using a 90 degree angle bracket at the twelve o'clock position or if you like the top connection of a jamb to a header.
This first image shows the joint created with the bracket inside the vertical C section and attaching to the underside of the headers flange.
This next picture is of the joint above being used in different drawing you'll note how the bracket is reversed whereby the flange connection is now outside of the C section and is therefore useless and not what I want.
I have tried changing both the bracket and vertical C sections internal UCS but it always shows the bracket outside as in the second picture.
I have no idea what I am doing wrong or for that matter how to fix this issue.
Hi,
How was the side rail drawn in your second image (full model)? If it was drawn using the Purlins macro (SEPurlin) then that is your problem. There is a known issue with applying user custom connections to beams drawn with this macro. The positions get confused. Try deleting the joint box around the purlins so they are independant and applying your joint again. It works fine for me on two manually drawn sections.
Aleck Giles, Structures Consultant, Graitec
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HI,
As previously stated elsewhere User Connections have nothing to do with the UCS. They are controlled by the internal UCS of the driver objects selected - mostly Driver 1. It is not possible to change the internal UCS of a beam after it has been created.
Therefore a joint at the Start of a beam to a passing main beam would likely be considered at a different orientation to a joint at the End of the same beam. Unless a joint is symmetrical it is not likely you will be able to get the same joitn to work at both ends of a beam.
If you want the same joint at the top and bottom of your post you will probably need to make 2 user connections. If you draw some posts bottom up and others top down you will have to guess which joint will work when you place them. If you are consistent and draw all posts bottom up then you should be safe calling the two joint versions "Top" and "Bottom" and using them accordingly.
Aleck Giles, Structures Consultant, Graitec
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Guys, many thanks for all your help on this matter and special thanks to @muleman1 for taking the time to create a screencast - very helpful for the reverse beam situation, not something we've had to do but certainly worth considering for certain situations.
So, I am really happy to say that I have it working now, given the advice and help I've received here.
Where I was going wrong was when creating the joint in the 12 o'clock position I was selecting the drivers incorrectly, in my mind I had the vertical section as the Column or Driver 1 and the horizontal as the Beam or Driver 2. Once I had swapped these around to the Beam being Driver 1 and the column being Driver 2 it worked perfectly.
This change hadn't fully sunk in as when I moved onto the joint in the 6 ' o'clock position I was still selecting the vertical section as the column and needless to say it didn't work correctly but again swapping the Drivers around done the trick.
The 3 and 9 o'clock positions were relatively easy, re-drawing the bracket in a top view, rotating and folding it relative to where it was to be placed in the least amount of moves had them working in no time.
Anyway, here's the output
Again, many thanks for your help and advice I'll no doubt be back for more!