Revit Structure Tutorial – Problems drawing Channels and Angle

Have you ever found that when using sections such as Channels and angles the default insertion is on the centroid of the structural member? This can be very frustrating and makes accurate placement of these members very time consuming.

There is a fairly simple way of fixing this problem and adjusting the family files so the sections draw and behave in a more rational way and in this short tutorial I will reveal all!

The above image shows the problem while drawing an angle, you can see that the reference plane was my intended steel centre but the angle is drawn at a strange location. This location is actually the centroid of the steel section but is not very useful for the technician! In the below example you can see the default Autodesk angle profile with two parameters that control the centroid and insertion position. These are the x and y parameters.

What I have done for the angle is edited the x and y parameters to equal half of the section width and depth so that the section is drawn down my desired centre line. This then makes it easy to control the lateral justification as you can see in the below image:

To edit the x and y parameters effectively you will need to edit the type catalogue TXT file. This is found in the same location as your Revit Family file (.rfa). In order for the type catalogue TXT file to work it has to have exactly the same name as the rfa. See image below:

To make life easier, I like to edit the text file in Microsoft Excel as the data is then presented in neat columns and you can use formulae and other tools to help develop type catalogues very quickly. As you can see from the example below, I have used a simple formula to calculate the centre of the sections.

Once this is done you can simply save the excel sheet as a CSV (comma delaminated) file and then rename this to text file (.txt).

As this may be the first time some of you have edited a type catalogue I have made a short YouTube Video to assist your understanding.



Autodesk Project Falcon

Autodesk Project Falcon is a technology preview of wind tunnel simulation software that is free to download from Autodesk Labs. It is branded, not surprisingly, at the manufacturing and product design areas but I have been looking at this for early conceptual studies on unusual structural shapes to help understand the effects of wind speed, eddies and implied wind pressures.

The best thing about project Falcon is the ease of use, open it up, import an STL file and use the on screen tools to set wind direction, speed and wind axis. You will then see a conceptual 2D analysis as shown above on my conceptual structure. You can then move the 2D plane across the structure to study wind speeds and pressures at different locations around the structure. If you have time, you can set Falcon to show flow lines using the 3D simulation which takes into account the whole shape rather that a 2D slice. I first tested the tool out on a number of simple shapes just to get an understanding of how the software works. I created the shapes in AutoCAD using solids and then created STL files by typing STLOUT at the command prompt.

You can take models directly from Revit if you have the STL output loaded or save as an ACIS solid and then open in AutoCAD.

Anyway, if you have time I urge you to take a look at this. Apart from being really good fun it may help Engineers understand the way pressures can build up around complex shapes on structures.



Structural Columns – Family Category and Parameters

Now we are all back into the full swing of things after the Christmas break I thought I would share some in-depth information relating to the parameters of structural column families. As you may already be aware, Revit Structure will automatically cut back steel beams to columns but will make in situ beams connect and become monolithic with columns. Sometimes hidden detail will be drawn within the family and other times Revit Structure seems to generate its own hidden lines! In this post I will show some of the parameters relating to Structural Columns to hopefully allow a greater understanding of how column and beam families behave within a project. Let us start with the Family Category and Parameters dialog box.

The family Parameters shown are dependent on the Structural Material Type that is selected. The below example shows the difference between the Steel, Timber and Precast Concrete and Concrete material types, it is also worth noting that these material types only affect the behaviour of the column and has nothing to do with the physical material.

Hidden detail can be automatically generated for Concrete and Precast columns but will need to be drawn with detail lines for the Steel, Timber and Other Material Types. These properties can be very useful if your column has fairly complex geometry and you want to control what hidden lines to show. You have the ability to select from the following when using Concrete or Precast material types:

  • All Edges
  • Edges Hidden by column itself
  • Edges Hidden by Other Members