Post-Tension Cable Idea for Revit! (wish)

[asaastad]

I've been avoiding them too. A tool would be nice but it's hard to model them too precisely with sweeps especially if the radius of a bend is curved so it creates a helical curve. I've done some stuff for some monorail beams and what I ended up doing was modeling the concrete down to the blockouts at the tendon ends and just made 2d groups for the elevation and plan view of each tendon. I came up with some solutions for modeling the tendons but it wasn't worth the extra time to have them in 3d when our main concern was getting the concrete detailed right.

I think the main wish I would have in addition or before a post-tensioning tool would be the ability to create model lines than have end points that can be drug in any direction instead of just within the plane it was created on, that way in addition to creating post tension cables we could do sweeps for object with similar curves like railings and spiraled stringers, etc.

[tvanryn]

jhniopek's example has helped a lot, but it looks more appropriate to steel detailing. I will hopefully be able to complete my version next week, which is a more schematic approach (I don't need to see the pan). I plan to create a line-based family with a live end, a dead end and a duct. It will have the ability to be flipped, and each part will be able to be turned on or off. For curved areas I am hoping to just be able to join the sections with lines and splines. I also want to build a chair height family that is basically just a big dot that I can position along the duct. This will all be 2D and text. I will post it when complete.

Tom

Oops, I forgot. I'm also going to try to create another family that will allow me to show PT's in a beam elevation view. Lot's of experimenting there.

[gkite]

A parametric 3D family is desperately needed however, the parabolic shape of the cables presents a real challenge in getting them to flex properly. I firmly believe that this is an item that the factory should have at the top of their to-do list.

[tvanryn]

Okay, here is what I came up with for my first really simple PT family...

This line-based family is made up of three components:
PT Head
PT Cable
PT Tail

Each can be turned on or off as needed. For example, when I have a cable that has a curved section I simply turn off the head of one cable and the tail of another, and use a spline Detail Line to link the two pieces. There is also a direction tool that will flip the head and tail.

The Chair Height Dots are another family. They are just a solid-filled region that can be placed directly on the PT family.

All of the text is simply text boxes.

If anyone has questions, or would like to tweak this, please feel free. I just ask that you post improvements for everyone to share!

Tom

[wrartes]

Any new advance on this matter.

[djn]

I think at minimum Revit should have tools for putting PT in Tendons in a 2D mannner, and then the could work on creating the more complex 3D tendons. Having nothing is a disgrace. Right now it would be almost impossible to create a 2D family that would take care of tendons through offsetting columns and around openings with the correct edge offsets, bending radius and tendon angle.

[khanson-3b]

I have tried and tried to make a 2d tendon component w/ no luck. What I would like to see is a multiple line tool like they had in autocad, that could be used to do a quick filled region, so that you can create something quick and easy that looks different from a line.

[irchrismm]

As of right now, we are doing all the 3D elements in AutoCAD, and having it imported into Revit. Unfortunately we are slow to respond to Revit, and only a couple of us have tried to pursue it. Now it is coming more and more a requirement to provide full 3D drawings to be added to the BIM. So, like everyone else, we are looking at either getting a program that is external to export to Revit, or make one ourselves. So far, I have not found anything that will work, and keep all the data that would be required for Bill of materials, and Stressing information to be included. ADAPT has a deal that says it can do PT, but all the Demo's and text on their site is all rebar related. AutoCAD takes forever.

[m20roxxers]

For realistic PT in 3D I would recommend Rhino and Grasshopper, though it does not do analysis, it is extremly flexible for 3D presentations.

[vonfmetz]

I appreciate the discussion so far. I like the pt cable example but do you not use cables pulled both ways? I am currently trying to manipulate pt cable family to have the option at both ends.