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Best Practices for Modeling a Steel Frame

Question asked by Aaron Gradeen on Dec 6, 2019
Latest reply on Dec 13, 2019 by Sergio Monti

I would like to hear people's opinions on the most time effective way of modeling a relatively small steel structure. Let's say it's a mezzanine. There are two ways to do it in my mind. One focuses on fast 3D modeling and the other focuses on fast drawing production I believe. 

1) Create the entire structure in a single part as a weldment. 



- incredibly simple to drive the entire structure with a 3D sketch. This makes the structure easy to modify in terms of overall dimensions or footprint. 

- The trim to body command is available so it is very easy to trim bolted beam to beam connections with a weld gap

- Weldment cut list reliably shows all beam cut lengths

- Sketch driven pattern can be used to locate base plates.

-When creating bolt holes, it's easy to specify specific bodies which contain the bolt hole. 

- You can use the combine command to create bodies which are the actual weldments (i.e. beams with angle clips or gusset plates welded on)

-Easy to change the elevation of weldments using the locate profile feature



- All individual parts reside as a body in the single weldment part. To create drawings of the individual parts (actual weldments) requires a drawing view where you have to select the body of interest. This takes a lot of time. 

- You essentially cannot reuse parts in this case. 

-Tough to automate custom properties of bodies in the cut list. I.e. drawing title can easily be programmed to be the part file name when parts reside in an assembly. You obviously don't have that option in this case.


2) Create an assembly which is driven by a 3D driving sketch



- you can reuse parts. 

-Easy to use replace model or save as to quickly reproduce drawings of similar beams. 

-Potential to use APIs to automate the drawing process for each individual part. 



-Cannot trim to bodies using external references. 

-Mating everything can be quite time consuming.  

-Having in context references in assemblies (i.e. holes in beams referenced to separate angle clip parts) can easily lead to potential reference errors in my experience. 


The assembly obviously isn't really a weldment so I have a hard time arguing for method 1 but I can see the benefits for ease of modeling. How would you model the structural frame below if you knew it was subject to design changes as you were modeling? 

Constructive comments are greatly appreciated.