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Replacing truss with other truss, without redoing everything

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Anyone have a method of replacing one type of truss with another? When I do a drawing of a truss layout using one brand/model and then the rental house asks to swap out for another, I'd like not to have to redraw the rig.


I know that "replace with symbol" has been requested. Until then...


Thanks, Scott

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Nope, as soon as you replace the symbol (which changes the cross section from what I can see) it breaks all your connections.  I ran into this many times already.  I have not found an easy fix but you can just grab each piece individually and the snapping should work again.  if you replaced it correctly it should have all the same coords, so all you need to do is snap that connection again.  just make sure all your cross section ID's match or the connection wont happen.

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  • 2 months later...

I really hope 2019 makes Braceworks more usable in real world situations.    Stuff like truss substitutions is not an uncommon occurrence.    It doesn't take much for motors and connections to break/disconnect and you spend almost as much time tracking down all the ridiculous errors, re-inserting, re-attaching crap as the time it would take to calculate point loads manually.  When it works it's great,  but man when your in the thick of it trying to knockout updates and recalculate,  it sure doesn't take much to send it all sideways quick.

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I hope so as well. I'm working on a drawing right now that has over 270 10' sticks of truss. I have quotes for rentals and the vendor who carries another brand has a wicked price, but I'd have to change everything. Not that a direct replace function would work, they have 8' sticks for me.

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Also keep in mind that very few popular manufacturers have actually given vectorworks the cross section data, which means even if you have a brand switch, its likely you will have to use a custom cross section anyways... and without some numbers you cannot accurately rely on the numbers BW gives you.  It will be a fantastic platform when they figure out all the kinks 

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21 hours ago, SCParker said:

I hope so as well. I'm working on a drawing right now that has over 270 10' sticks of truss. I have quotes for rentals and the vendor who carries another brand has a wicked price, but I'd have to change everything. Not that a direct replace function would work, they have 8' sticks for me.


Right,  a 1 to 1 replacement isn't always going to work,  I think there is still a very real place for the truss PIO's in the workflow  (I am often running calculations in early stages in ballrooms to make sure we aren't designing ourselves into a corner).  But even with that,  if you change the PIO from say, 12x12 to 20.5x all the motors disconnect,  and off you go reconnecting...   I understand the argument that the PIO doesn't have cross-section info (which also isn't included for most US manufacturers anyway).   (though I think you can add it),  but provided the person doing the preliminary truss layout/rigging drawings isn't a complete idiot,  I don't see how rigid is completely useless,  if you understand the loads (center point and distributed) allowed on various spans of different sizes of truss,  how is a rigid load calculation that much different than using something like Harry Donovan's rules of thumb?   Which a lot of people have been using for years?  I'm usually looking for ballpark #s anyway to help determine if things need further investigation by people more qualified than I.   More of a starting point,  than the law. Feel free to correct me if I'm being dense.

Edited by Wesley Burrows
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Hey sir, I will quote directly from engineers here.


I reached out to our engineering team for some clarification and to see if they could explain why the calculations are showing what they are. In your calculation, all materials are stiff so there is no deflection in the system. This is because you have not selected a cross section for the hoist and there is no cross-section data for the TC12 today in Braceworks. If you place a load directly under a hoist normally all the load goes into this hoist. If this was a flexible system, some load would go into the dead hangs as well because of the chain lengthen from the hoist and the stiffness from the truss. However, there is no lengthen on a rigid frame so all the load goes into the

middle hoist. If you would add a user cross-section for the truss and the right stiffness for the hoists, you would get different results



Rigid is basically the worst calculation you can use.  With no deflection in the system whatsoever the weight distribution is not even close.  For instance in this scenario I had a 1050lb audio dead hang on a 10ft spanner truss.  taking the safety factor into account the calculation had 2200 lbs on the deadhang and next to nothing on the motors.


There is also a chain leveling function that needs to be worked in as well that will greatly effect your numbers.  In my biggest setup recently here at LVCC I had 3300 ft of truss with a huge number of motors.  I was using XSF truss (which wasnt loaded in at the time) and put load cells on key points and the numbers were consistently 30-40% heavier then were calculated.  BW is nice, but in many ways you really do need to really know whats going on.  The donovan thumbs are a good place to fall back to always but there are a lot of calculation safety factors built in for deflection, force, torsion force and bending force and momentum force that you HAVE to have accurate cross section data or its useless.

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oh yeah!  I would LOVE for everyone to stop using tomcat, A because they are twice as expensive as they need to be, and B they are a@@holes... but I digress... I know that you cannot make up cross section data, and I applaud you for not hiding that fact in a product... but without the data, the product is flawed... you CANNOT rely on the numbers that braceworks spits out with wrong information.  I have put the loads on load cells like I said and the true weights are far heavier.  even WITH a 2:1 safety factor built in.  loads do not transfer to dead hangs correctly, etc.  do not get me wrong, I really do love the product, but its serious flaws have made me just simply stop using it altogether until the data is in there for more than just a simple audio hang on a single motor with no trussing whatsoever.  has there been any chain cross section data uploaded at all or is all the chain still rigid?

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