Space Frame Structure

[Anonymous]

Hi all,

I'm looking to build a space frame which can be exported to Dlubal RSTAB which determines the force in each member of a space frame under given load conditions. The quickest way to build a complex space frame in RSTAB is to build it in Revit and import it.

The shape of the frame is complex and so I have modelled the shape of the surface as an in-place mass and then divided it. I then created a custom pattern family which incorporates the space frame geometry. This pattern is then loaded back into the mass hence creating the space frame structure. The problem I have is RSTAB only imports structural members. Because the space frame members are created using extrusions etc in the pattern based family it does not register them as structural members.

Is there any way to import circular hollow sections into a pattern based family? Or does anyone have any ideas how to model the space frame such that RSTAB registers the members are being structural?

Thanks in advance!!

Murray 😄

[ToanDN]

Use adaptive family and change the category to structural frame, then place it in the mass nodes and repeat it.

[Anonymous]

Hi there,

Thanks for your prompt reply. Use adaptive family for what sorry? Creating the roof itself or the pattern? Apologies, I am relatively new to the whole creating custom families business.. 

[ToanDN]

I was thinking not using pattern based to populate the space frame, but use an adaptive structural frame and repeat it on the divided surfaces. But I am retracting it because you may want a special pattern for the design. Edit your pattern based generic family and see if you can change it to structural framing category. If it can then you are good to go.

[Anonymous]

Yeah that's the problem, because the surface of the roof is a rather complex shape this wouldn't be possible. How do I change the category of a family? 

[ToanDN]

I think there is a misunderstanding. What I said has nothing to do with the complexity of the shape of the roof, but how you design the pattern of the space frame. Can you share a screen shot how it looks?

To change a family category, edit the family, click on the yelow button above or below (i am not in front of the 'puter) the edit family type button, then select the new category.

[Anonymous]

Sorry I am a little confused. Here is a photo of what i've got so far. The shape is not final, but won't be far from this. Also, for some reason the space frame is appearing upside down, but you get the idea. What is your thoughts?

[Anonymous]

Also... I've placed the pattern family in the pattern as shown in the photo, but when trying to change the category there is limited options. Any ideas? 😞 

[ToanDN]

That is a very simple pattern and I think either way I mentioned earlier should do. I can show you when I get back to my computer.

[Anonymous]

That would be much appreciated 😄 thank you for all your help again!

[ToanDN · Accepted solution]

Upon starting the example file I realized you cannot change any adaptive based family (generic pattern based, curtain pattern based, generic adaptive, mass) to the Structural Framing category.  So you need a different approach:

1. Create a conceptual mass, divide the surface and set UV properly

2. Create a generic pattern based family with only Model Lines

3. Assign the generic pattern based family to the mass divided surface

4a. Place structural frame using pick line and pick the skeleton manually

4b. Alternately, you can employ Dynamo to place them more automatically (I don't know how yet)

It is more work than I had anticipated due to the category limitation but it's doable.  2017 File attached. 

[Anonymous]

Hi Toan,

I have created it this morning and it has worked perfect. You are a genius! Thank you ever so much for all your help 

Murray