BIM & BEAM

Concrete Beam Hidden Line Display Parameter

In Autodesk Revit Structure, we can get different hidden lines by setting a parameter called: Display in Hidden Views

Use the following case to explain how to:

There is a floor and a T shape beam under the floor (See Figure 1).

                                                (Figure 1)

Select the beam and click edit family. In beam family editor, open family category and parameters dialog, for parameter "Display in hidden views", there are 3 options (See Figure 2):

1. Edges Hidden by Beam Itself

2. Edges Hidden by Other Members

3. All Edges

 

                (Figure 2)

Let's apply the 3 parameters and compare the differences:

1. Edges Hidden by Beam Itself, only show beam edges in hidden line which are hidden by beam itself (See Figure 3)

                                                (Figure 3)

2. Edges Hidden by Other Members, only show beam edges which are hidden by floor (other member) (See Figure 4).

                                                (Figure 4)

3. All Edges, represents edges including 1 & 2 (See Figure 5):

                                               (Figure 5)

You can also find this parameter in concrete column family editor as well.

Revit Structure 2010 Slanted Column Parameters

Slanted columns are becoming more and more common in larger high-profile structures. The architectural forms that engineers are being required to support are getting more complex.

Engineers and drafters can now create slanted columns using the same column families they have used for vertical columns, which include not only physical characteristics, but also analytical as well.

The avi: http://revit.downloads.autodesk.com/download/Structure2010/Blog/Slanted Columns Parameters.avi will demonstrate how to utilize the tool and explain the parameters within the element properties to show how they will affect the location of the slanted columns to the supported members.

These new Slanted Column properties include the following:

- Column style parameter

• Slanted – Angle Driven
• Slanted – End Point Driven

- Column Cutback

    Beam/Column Joins editor

- Column Joins parameters

• Top/Base Attachment Type
• Top/Base Attachment Distance
• Top/Base Attachment Referenced End
• Top Geometry Treatment
• Base Geometry Treatment
• Offset From Attachment at Base
• Offset From Attachment At Top

- Column Attachments parameter

• Move Top With Grids
• Move Base With Grids

- Cross Section Rotation parameter

 

Black Level vs. Blue Level

When importing structural model, the levels show black as Fig1. In the project browser, Level 3 & Level 4 will not show up.

 

What's the difference between black and blue levels? How to turn the levels from black to blue?

The black indicates the level is not mapped to any floor plan, while the blue means the level is mapped with a floor plan.

To map a floor plan to a level, here are the steps,

• Go to the View tab> Create panel> Plan Views> Structural Plan

• From the New Plan dialog, select the levels for which you want to create new Floor Plan Views.

 

Go back to South View, the black levels turn to blue, and in the project browser, the Level 3 & Level 4 will show up.

  

“Do Not Break At Inserts” type parameter for a wall foundation with continuous footing

Hi All,

Just want to share a little tips & tricks with you.

One of my users was trying to create some openings touching the bottom of a wall foundation with continuous footing. The methods that he used to create the openings were:

1) Wall Opening tool

2) Edit Profile on Wall Sketch

He then went to the Wall Foundation Type Properties and try to use the "Do Not Break At Inserts" parameter:

 

However, as illustrated below he realized that regardless of whether this "Do Not Break At Inserts" is checked or not, he did not see a difference in its behavior. So both of his previous methods of creating openings by thinking that would be an insert and the footing would not break at them if they broke the bottom of the wall, but it appeared to have no effect:

So what does this parameter actually do?

This user approach and thinking was good, except that currently the Wall Opening or Edit Profile on Wall Sketch tools will not be affected by this "Do Not Break At Inserts" parameter.

Currently, this "Do Not Break At Inserts" parameter would only work if the openings are created by using the Windows and Doors .rfa family, for example:

3) Door-Opening.rfa

4) Window-Square Opening.rfa

5) Opening-Door.rfa (as Generic Model)

6) Opening-Window-Square.rfa (as Generic Model)

Thanks

Wai

What effect this Cap family parameter has on a Structural Foundation family?

In the last several months, I got some emails from customers asking what effect this Cap family parameter has on a Structural Foundation family?

 

This parameter is designed to determine the elevation of the bottom of the footing.

If Cap is selected, the Bottom Elevation will be taken from the "Topmost Bottom-facing Face".

If Cap is not selected, Bottom Elevation will be taken from the "Bottommost Bottom-facing Face".  To see this, refer to the following picture:

 

 From the below picture which is captured from the project file, we can easily find that the value of  "Elevation at Bottom" is different between the "Cap" checked and unchecked.

Slab Edge Hidden Lines Display

Back in February/March 2008, during our Revit Structure 2008 Beta testing period, there was a discussion among our Beta testers (from different countries) about the slab edge hidden line display. In fact, the standard or culture of displaying slab edge hidden lines on plan could be different from country to country.

For example, many USA companies have a standard to show the inside (or bearing) line to be displayed for slab edges.

However, some other countries users have also told us that their standard is to display both/all lines which is:

 

I would like to share a technique with you in Revit Structure 2009 of which one of our QA expert Joe Charpentier has explained in the Beta discussion forum an option, to be invoked via the Revit.ini file, that can change the display of hidden lines. Quote:

"By default, the inside (or bearing) line will be displayed for slab edges.

In the official release of Revit Structure 2009, we are providing an option, to be invoked via the Revit.ini file (typically located at C:\Program Files\Revit Structure 2009\Program), that can change the display of hidden lines.  This is similar in behavior to the "Show hidden lines" options for beam families.

Add the following section heading and variable names to the Revit.ini file, if it doesn't exist already:

[Graphics]
HiddenSlabEdge=All

Possible values for HiddenSlabEdge variable:
"All"  - Show all lines from a slab edge
"Itself"  - New default behavior, the "Bearing" or lower edges
"Other" - The edge intersecting with the slab, (Beta 1 and 2 Behavior)
"None" - Show no hidden lines for Slab edges (r2008 behavior)

Note that this is not set for the project, but for the session of Revit.  That is, if you open a file with a certain variable setting, that will not prevent the project from being displayed differently if opened in a different install with a different setting."

Thanks

Wai

Is it possible to import accurately an "almost orthogonal" DWG/DXF Line into Revit?

Some users have reported that when they tried to import/link a dwg/dxf file representing the property boundary (where one of the boundary is accurately measured with 90 degrees, 0 minutes and 30 something seconds; or there is a deviation of 3/8” over the length of the site) provided by the property surveyor, Revit will treat and round up those angles as exactly 90 degrees.

They would like to know how they might set up their models to account for this level of accuracy, or explain the thinking behind this rounding up by Revit.

Here is the technical explanation.

Revit requires almost-vertical and almost-parallel lines (where "almost" is defined as 0.02 degree off or something like that) to be made exactly vertical or horizontal in order for our Geometry engine to work properly. This code applies to the imported lines as well. That’s why when importing a DWG/DXF with “almost orthogonal” or “very sharp angle” line, Revit will somehow “straighten” it for the Geometry engine purposes.

For now, here is a workaround that for users to input exactly the 90 degrees, 0 minutes and 30 something seconds:

1-     Import the DWG/DXF in Revit (yes, I know that some of “almost orthogonal” line will become “straightened”)

2-     Go to Site > Property Line > Create property lines by sketching

3-     In sketch mode, use Pick Lines tool and select all the imported DXF lines.

4-     Finish sketch

5-     Click on the Revit generated Property Line and then on the option bar Edit Table

6-     Now you can do the adjustment by inputting/adding back the 30 something seconds into the original “almost orthogonal” line. (See below jpgs)

Structural framing underneath a warped slab

Some users have asked me what is the best and quick way to place a beam or beam system to a warped slab (Figure 1)?

(Figure 1)

Currently, a slab cannot host a beam or beam system. However, if users have already added the columns, they can then attach the columns to the underside of the slab (Figure 2).

(Figure 2)

Then in the Plan or {3D} view, users can use the regular Beam tool with "3D Snapping" option checked in order to layout quickly the perimeter girder beams (Figure 3).

(Figure 3)

Finally in the Plan view, user can add the Beam System with "3D" option checked in order to populate the joists to achieve the desired goal (Figure 4).

   

(Figure 4)

Adjusting beam elevation based on slab thickness

When using the Beam tool to layout the framing on plan, by default the current Level has already been selected by Revit as the Work Plane. Therefore, if user draws the beams, they will be referenced to the Level itself only (Figure 1).

(Figure 1)

Also, user has to manually adjust the beams Properties Start Level Offset and End Level Offset so that the position of beams will match the thickness of Slab. By consequent, if the thickness of Slab changes, the beams will not follow or auto-adjust with the Slab (Figure 2).

(Figure 2)

Currently, Revit Structure doesn't have a direct feature to "attach" beams to slab. However, there is a solution to quickly draw beams that will associate with the Slab instead of the Level which is to use the 3D Snapping option when drawing the beams on plan (Figure 3). This option allows Revit to select automatically the underside face of the Slab geometry as Work Plane and places the beams underneath it. As a result, if the thickness of Slab changes, the beams will follow and auto-adjust with the Slab (Figure 4)

(Figure 3)

(Figure 4)

P.S. I know that some customers use the method of drawing the Ref. Plane by assigning it as the Work Plane, then aligning and locking it to the bottom of Slab. This method would work fine as long as the Slab is horizontally flat, but if user decides to make it sloped then the constraint will break and the beams will no longer follow the Slab.

Custom shape of stair stringer

One of my structural users specializing in industrial building type has sent me an email saying that he needs to model some exterior stairs with C-Channel stringers. However, he realizes that currently Revit Structure provides rectangular simple shape of stringer only (Figure 1).

(Figure 1)

Currently, Revit Structure doesn't have the ability to create custom shape of stringers. However, there are several workarounds to achieve that and the one that I would like to show you is an alternative use of Railing tool. Here are the steps:

- First, you need to turn off the Stair Stringer by setting the Right Stringer and Left Stringer parameter value to None (Figure 2).

(Figure 2)

- You can then turn on the visibility of Railing category that was turned off by default in Visibility/Graphics (Figure 3).

(Figure 3)

- You can now select the Railing geometry and go to the Properties in order to modify the Rail Structure type parameter. In the Edit Rails dialog box, you can assign your custom profile ex. C-Channel Profile and then adjust the Height and Offset so that it will be at same location as the stringers (Figure 4).

(Figure 4)

- In order to trim the bottom or top of the "fake" stringers, you can select and edit each Railing sketch by splitting the sketch line and assign the slope to "Flat" (Figure 5).

(Figure 5)