Auditing Navisworks models for distant elements

In a recent post on the Beyond Design blog, Lee Mullin illustrates some techniques for fixing a Navisworks composite model that has elements extremely far from the main model. Some symptoms of this problem may include:

• Holes in elements or triangles missing when you render
• Section plane in foreground when you are navigating
• Jerky performance when navigating
• Model disappears when navigating
• Two faces apparently occupying the same space giving a jagged surface

Click here to read the rest of Lee’s blog post.

Graphics Cards - Optimus technology

Some of the newer laptops that are coming through often have a feature called Optimus technology enabled. More details can be found here on what Optimus technology is.

Whilst this is great technology, it can play havoc with your design software, often using the wrong card to driver the software. So what can you do to ensure that your software is using the better graphics card in your laptop? Whilst you could use the drivers to manage the software, often the results are not what you expect. Therefore, you need to boot into the bios and turn off the Optimus technology feature; this will disable the Intel card and force the Nvidia card to be used instead.

The Optimus technology acts as a switch between the 2 video cards. One screen would use Intel and the other Nvidia. When the laptop is not docked in a docking station, the Intel card is the preferred card to save on power consumption. Unfortunately, we don’t care about the power savings and want Revit to perform. Disabling the Optimus switching mechanism forces the computer to use the Nvidia card in all hardware profiles. It’d be nice if Optimus could auto-negotiate which card to use based on the power needs, but sadly is doesn’t.

Once you have disabled the Optimus technology you will need to do a couple of restarts to get windows to reinstall the Nvidia drivers. It should be noted that not all of  laptops have these dual card installed, but where you do have them, disabling Optimus, without doubt helps.

Why Windows in Revit Don’t Cut it.

Brok Howard, BIM manager for our St Louis office gives some advice on why windows don’t cut.

We ran into an issue last week where a window family was not cutting in plan as would be expected. For example purposes I will demonstrate what was happening and why this might happen with your window content. I will use the out of the box content that ships with Revit if you want to follow along. It also starts to address how this might be useful for some instances.

In the example below we have three windows, each at different sill heights.

The first one cuts as expected, the second is going through the sill and the third is above the cut plane of the view. The view is set to 4’-0” and in the elevation above I am showing where this is cut in the view.

Again, this would be as expected. If we move the cut plane in the view up, so it only cuts the second two windows, we no longer see the window below in plan.

No, for the interesting part of how windows work. The assumption we have made so far is that when you move the view range cut plan that is what is changing the way the window is being cut. Let’s investigate this further by opening up this family.

Opening the family and then looking at the Floor Line view shows us this.

Notice on the Properties pallet we do not see any information about a cut plane.

Now click where the Family:Windows drop down menu in the this section and change it to Floor Plan:Floor Line, now you are seeing the view propery settings.

Now click on View Range. You will find that the default Cut Plane for this view is set to 4’-0”, same as the model.

Let’s now change this to 7’-0”.

The other thing we are going to change is we are going to remove the symbolic lines in the family so we are seeing the real solid geometry.

And finally we are going change the default sill height to 6’-0”. You should end up with something that looks like this.

When we load this new family into the project we end up losing the second windows in plan. This is due to the fact that the symbolic lines were really what was being represented in plan, not the window. What we are seeing is the opening from the family.

Now, we will go back to the family and change the geometry to now show in plan by selecting them and changing the settings to show in plan.

Now we are seeing the family in its true modeled elements.

Note that now we are seeing the third window. Why are we able to see the window with the cut plane set to 4’-0”?

Because windows are not really cutting. They use the internal cutplane in the family in combination with symbolic lines.

But why is this? If you go to the Visibilty/Graphics Settings it clearly shows the option to cut them?

Now we will change the cut plane in the model to match the cut plane of the one in the family.

We see the geometry but not what you would think, now select one of the windows. All the detail is there, but we only see it as if it was not cutting.

Now change the default sill height in the family back to 3’-0” and the cut plane back to 4’-0” and reload the family back into the project. Now change the floor plan view range back to 4’-0”. What you get is this.

Until window families are really, truly cutable geometry this is what you will get. And if you have ever created window content from scratch, this will be important to keep in mind because you will need to make all your window geometry content not show in plan and not cutable, then use symbolic lines to make them show correct in plan.

This is the farthest family from BIM that I have found so far, it would be good if Autodesk addresses issues like then rather than create workarounds. But at least now you are equipped with the WHY on windows.

The 2nd Annual HOK BIMies

Lachmi Khemlani  from AECbytes provides a great overview of the 2nd Annual HOK BIMies, be sure to check it out! We really do love what we do at HOK. :-)

http://www.aecbytes.com/feature/2012/HOK_BIM_Awards.html

Clipping Issues in Navisworks

From the Beyond Design blog post, “Why does my model look sectioned?”

If you are experiencing clipping issues in Navisworks – especially with large models – you may have a spurious object far away from the main geometry. Your best option is to delete the extraneous element in the source model and reload it. If your composite model is just that large (airport, neighborhood, city…) then you might need to adjust the Clippng Planes under the Culling tab in File Options.

Read the complete article on the Beyond Design blog for more info.

Event: BIM in Modular and Prefab Construction

HOK’s own James Vandezande is the president of the New York City Revit Users Group (nyc-rug.com) and organizes popular monthly meetings around various BIM-related topics. The January 2012 meeting featured guest speaker Ian Atkins who shared some of his real-world experience in applying BIM to modular and prefabricated construction.

Feel free to watch the recording of the meeting (Ian’s presentation starts at 12:30 into the recording)…

Enabling Better 3D Coordination

Not too long ago, some in the industry thought that simply by exporting Revit models into Navisworks meant they were performing 3D coordination.¹ I firmly believe we are moving beyond this notion towards a more complete offering of coordinated inter-disciplinary model deliverables.

I was inspired to write this article from recent posts by Steve Stafford on RevitOpEd (“Designing Revit Content – What is Interference?”), and posts by Doug Bowers on Applying Technology to Architecture (“Clearance Zones in Revit Families – Part 1 and Part 2”). In their writings, Steve and Doug share some great tips and techniques for architects to generate more accurate clash detection results. Without reiterating their information on this blog, here are some of the key concepts:

• Overlapping windows will not generate a warning in Revit
• Know what families have 3D geometry and which consist of 2D linework
• The door swing shown in plan is only a 2D symbol, unusable for clash detection
• Clearance zones are not included in Revit door families because the rules can be different around the world

The main issue here is not necessarily about detecting interferences between 3D geometry, but one concerning model validation using implied spatial zones. I use the term ‘model validation’ because this type of checking has a range of uses including code compliance and maintenance clearance validation. Some facility owners are now starting to include such specifications in their BIM requirements. For example, writing the project execution plan for a recent project I found the following requirement:

“Clearances and access: All clearances and access to equipment, valves, etc. must be modeled in 3D and kept in a separate layer and labeled correspondingly.”

If your existing content library doesn’t include clearance zones, you might be in for some heavy duty family revisions as this project gets started.

As an alternative, an intelligent model checking platform can validate many of these rules (but not necessarily all of them). One such program in use at HOK is Solibri Model Checker (www.solibri.com). While this is worthy of future dedicated posts, the fundamental idea here is ‘intelligent model checking.’ What makes this tool intelligent? It utilizes IFC (Industry Foundation Classes) models that ‘understand’ the model parts. Navisworks does a great job in checking the raw 3D geometry, but the system cannot distinguish between various building elements - such as a wall and a door - without user interaction in the form of property search sets. In IFC, the data is generated from a compatible BIM platform and elements are classified according to international standards. As such, Solibri can understand a door and apply validation rules (ADA) to the door without the need to add them into the native door family.

Note 1: “3D Coordination“ is a defined BIM use in the “Project Execution Planning Guidelines.” Read more about BIM use definitions at the Penn State University website (bim.psu.edu). We also encourage you to follow a new blog by HOK’s Greg Schleusner: bimuse.blogspot.com

Taking Revit into the future…..

David Light HOK London explains how HOK has adapted Revit for touch screen technology.

http://www.worldarchitecturenews.com/index.php?fuseaction=wanappln.projectview&upload_id=18396

DRAWING (S) in_form

 

I am proud to say that I received a copy of Disegno (E) in_Formazione today or DRAWING (S) in_form. I was contacted by Massimiliano Lo Turco earlier this year asking for an interview on HOK’s experiences with BIM; as always, I obliged. The book is bilingual Italian & English & includes a wealth of knowledge on BIM strategy & software deployment.

More detail can be found here….

http://www.bimacademy.it/2011/10/disegno-e-in_formazione-disegno-politecnico

Viewing thumbnails when loading families

Victor Martinez BIM Manager at HOK New York says; if you are loading families and want to view the icons in detail mode, hold your CTRL key down and middle mouse scroll in the window, the view will go from this:

To this:

The more you scroll with the CTRL key pressed the larger the icons will appear: