Using Structural Members in Complex Families

[bimtroublemaker]

My fundamental question is "How do you nest structural elements in complex families and retain the ability to schedule and analyze the elements?"

The example that i will use is as follows:

I created a parameter driven ring truss. I managed to get the family into a project, but then i couldn't schedule the individual elements because the "SHARED" tick box in the structural beam and column .RFAs weren't checked.

I went back and ticked the boxes, reimported the structural members, and then tried to reimport the host family into the project. Now I get the "REVIT HAS JUST HAD A SERIOUS ERROR" message and the family doesn't import at all. This 'shared' family is also attached.

I have tried using both the generic mass and complex structural element templates to accomplsh this, niether works.

I haven't even had a chance to try structural analysis but i don't have very high hopes.

We are having some major problems trying to get Revit Structure to work properly and the boss is considering chucking it and going back to Bentley (a fate worse than death!)

I could build the families as simple masses with profiles pretty easily, but then is there a way for me to analyze the element by implanting structural lines?

I am frustrated as all he77...I need help....and i am going to start pouting soon.

[m20roxxers]

Unfortunately they have to be all inplace or component families for the analytical lines to transfer across.

Even though you have the option to draw them at the end of the day the software supports nodes, bars and panels only. Inplace can only support bars the rest are all tied to the catagory of the system.

Using a number of techniques you can use the pick button to add them to parametric shape families though and then manipulate the family using this technique. Works reasonably well in most cases.

Are you simply trying to analysis the truss itself or the supports required for the truss?

Depending on what you are doing you can use different methods. The truss tool can do quite alot for simple trusses.

How and with what package are you trying to analyze the truss? Are you planning on applying releases and forces in Revit? Some of these elements can be just as easily done via a dxf or dwg depending on the program for complex beam systems.

[bimtroublemaker]

Hi Roxers Thanks for the reply

I am using REVIT STRUCTURE 2010. My current goal is to develop an understanding of what the program will and won't do, and whats the best workflow for our projects. One part of my exploration involves seeing what I can use in a parametric family and what I can't.

Its not really about this truss model, but rather figuring out how revit will analyze a structure or what happens when I send info to our existing analysis software....i have a big task in front of me!

So let me check my understanding of what you are saying:

>>Unfortunately they have to be all inplace or component families for the analytical lines to transfer across.

By this you mean inplace structural components must be created in a project (.RVT) rather than in the family editor (.RFA)? Structural elements in families don't work?

>>Even though you have the option to draw them at the end of the day the software supports nodes, bars and panels only. Inplace can only support bars the rest are all tied to the catagory of the system.

So if I create structural elements in place, all I can get out of them are lines for analysis. I won't get the nodes that link beams to columns, thus no parameter driven fun. The rest of what is tied to the category?

>>Using a number of techniques you can use the pick button to add them to parametric shape families though and then manipulate the family using this technique. Works reasonably well in most cases.

Tried this before. Linked structural elements to the line work but when I changed the parameters for the line work, the structural elements didn't follow the family. I am an odd case I guess =o(

I tried doing some inplace family work to make a beam inside a project. I put a line down the middle of beam and made sure it was ANALYTICAL type. Unfortunately no scheduling information carried through (length, elevation, etc.). Is it possible to create in-place structural elements and then schedule them? What did I do wrong?

Many thanks for your assistance!

TBT

[m20roxxers]

By this you mean inplace structural components must be created in a project (.RVT) rather than in the family editor (.RFA)? Structural elements in families don't work?

Sorry I misspoke, what I mean is the component families of beams and columns work fine from an analytical perspective. However if you try and draw your own analytical lines in families these will not translate. This is due to the way beams and columns are end point driven to for a linear analytical element, anything outside of the this doesn't get taken into account.



So if I create structural elements in place, all I can get out of them are lines for analysis. I won't get the nodes that link beams to columns, thus no parameter driven fun. The rest of what is tied to the category??

Depends on the analytical package you use, all linear analytical elements are 2 nodes connected via a relationship. Technically a linear element is there for additional abilities to affect the node points by applying forces to the length.You should have no problems, again depends on the package but almost all work by creating these points. They just don't develop area's to place points on with inplace families.



I tried doing some inplace family work to make a beam inside a project. I put a line down the middle of beam and made sure it was ANALYTICAL type. Unfortunately no scheduling information carried through (length, elevation, etc.). Is it possible to create in-place structural elements and then schedule them? What did I do wrong?
TBT

Not too sure about the scheduling, while you will be able to create a schedule of the inplace element obviously you won't be able to create a parametric item that allows full counts of all items unless you build alot of functionality into it.

What sort of information are you looking for? Just the members and sizings/area's or something regarding the Analytical information.

ODBC exporting really has alot more data on this side of things depending on what you want to extract.

[dbaldacchino]

Hey there :)

I don't believe what you're trying is possible. More than a year ago I tried doing a custom Portal Frame family with analytical and it didn't work correctly (our engineers use Robot Millenium and it wasn't reading the analytical correctly). I opened a support request with Autodesk to confirm and they said that there were known bugs. The case hasn't been updated since so I don't know where they stand.

We have also tried nesting a structural column family in an overhead coiling door once, but the member won't flex as one would expect it. That would be very similar to the thing you're trying to do. I would suggest that you build a "layout" family to help you get your shape and size set correctly (a stick-figure of sorts) and then dress it up with the actual framing members using 3d snapping etc. I know, a pain for sure, but it's probably your only option at this point. Maybe build one section like you did in the family and array it. If the grouped elements give you a hard time when reading analytical info., then ungroup and try again. I don't think line-based families were meant tobe nested. If I remember correctly when you nest them and make them shared, they default to their family default length and that obviously defeats the purpose of building a complex parameteric family in the first place!