The Revit Clinic

Visible/Invisible?

Controlling visibility in a family can be interesting.  Do you want certain geometry to only display when a certain condition is met in your family?  If so, then today’s post is for you. 

I would like to talk about using a parameter in the family to control the visibility of an object using an If/then formula.   If/then statements are very powerful as formulas inside a family.  You can do all kinds of interesting and very cool things with them.   The way you use an If/then statement can vary with the type of parameter that you are using.  A parameter can be anyone of these types:

• Text
• Integer
• Number
• Length
• Area
• Volume
• Angle
• Slope
• Currency
• URL
• Material
• Yes/no

Anyone of these types can use an If/then statement in a formula to control its value.  Today, I want to talk about the Yes/No type and its use of If/then statements. 

Yes/No parameters are controlled a little bit differently than the other types.  The other types need a complex expression to determine the value of the parameter, while Yes/No only requires a statement.  If the statement is True then the value for the parameter is Yes (checked).  If the statement is False then the value for the Parameter is No (unchecked).

Let’s take a look at an example:

 

In this example, I have created a Yes/No Parameter in a family and created formula in the parameter that says if the parameter Length is equal to 4’ then the BoxVisible Parameter will be Yes. 

Your formulas can be much more complex than this if you want, but this is basically how it is done. 

The next step is to link the Yes/No parameter to the geometry that you want to control.  To do this, you will select the geometry in the family and open its element properties.  Next to is Visible parameter select the little box in the column with a heading of “=”.  You can then select your Yes/No parameter from the list.

 

Just like that you have created an If/then statement and a parameter to control the visibility of a piece of geometry in a family.  Go ahead and try it out.

Early bird gets the worm

While waiting to get lunch the other day, I bumped into one of our AEC User Researchers and she forwarded me information about some interesting things going on at AU.  I wanted to share it with you. 

Want to help improve the Autodesk AEC products you use every day and get an early opportunity to try out future releases?

This is your chance to participate in user research sessions at AU (or in the future) that will give us a deeper understanding of how you use our products and what we can do to improve them.

We conduct user research throughout the year, so we're  interested in hearing from you even if you can't participate at AU.

To learn more, you can either: Visit us  Online: http://www.autodesk.com/aecusability or in person:

• AEC Usability Center (Zeno room 4601 in the AEC Campus on  the 4th floor) for AutoCAD Architecture, AutoCAD MEP, Civil 3D, Revit  Architecture, Revit MEP, and Revit Structure
• Exhibit Hall Collaborative Project Management Usability  Booth (#354) for Autodesk Buzzsaw and Autodesk Constructware.

Thanks for your support. We look forward to seeing you there! 

James McElroy, on behalf of the AEC User Experience Team.

Cutting to Solve

Today I wanted to share a a troubleshooting tip with regard to Revit.  Sometimes, Revit objects get "stuck" for a lack of a better word.  Maybe the object isn't displaying they way it does it other projects or a setting change does not seem to affect the geometry on the object.  There is a great little Product Support tip that you can try to solve these problems. 

Try to Cut and Paste the object back into the same place.

This little trick has success because it in effect refreshes the Revit object and rebuilds its connection in the database.  I wouldn't try it with an entire model, but if you have a few objects not looking correct or cannot figure out why that error message is still listed in your Review warnings dialog box, try this.

Removing Slivers (Spaces)

You may have noticed when setting up energy data in a Revit project there is a parameter “Sliver Space Tolerance”.  So what exactly is a sliver space and even more important what exactly is this parameter telling Revit to do with it?

First we need to define what a sliver space is, why it is important, and finally how this parameter can help us.  A sliver space is one of those small areas in your building model where you would not typically place a room object.  Say for example a plumbing chase wall, or an area between a new and existing construction where a wall was framed out leaving a gap between new and old.  These kinds of spaces are sliver spaces.  Not every project ends up with these kinds of spaces, but many do.

 
Now that we know what a sliver space is, why is it important?  When the analytical model (gbXML file) is created for use in energy analysis software, the way a wall is defined as interior or exterior depends on adjacent room objects.  If a wall has rooms on both sides of it, the wall is defined as an interior wall.  If a wall has a room on only one side of it, the wall is defined as an exterior wall.  In the energy analysis interior and exterior walls transfer heat/energy at different rates, so for accurate results it is important to define these walls correctly.  This is where the sliver space now plays a role.  As Architects we typically would not place a room object into a chase, or a space between new and existing construction, there is no need for this.   However without a room in those sliver spaces the analytical model ends up with chase walls defined as exterior.  This incorrect assignment of wall will compromise the accuracy of the energy analysis.

Understanding what a sliver space is and how it affects the analytical model give some insight to what the “Sliver Space Tolerance” parameter does for us.  Setting this tolerance to a value above the width of any sliver spaces you might have in the project will allow Revit to ignore spaces smaller in width than the tolerance setting when creating the analytical model.  If the tolerance setting is correct you do not have to worry or go back and place “rooms” into these spaces in order to get an accurate analytical model of your project.

As long as we are talking about getting a good analytical model, I should mention there might be other small spaces (that are too large to be considered sliver spaces) that can cause walls to incorrectly be identified as exterior.  Look for small areas you would not typically place a room object into.  A closet or an elevator shaft would be an example.  These areas are going to be too wide to be considered sliver spaces but still need to be accounted for so you do not leave “voids” in the analytical model.  You will need to place room objects into these spaces in order to get an accurate analytical model.  Don’t forget to use some kind of filter if you don’t want these spaces appearing in schedules.

Understanding these sliver spaces (and other small spaces) can lead to better and more accurate analytical models.  Spending the extra time upfront to account for these spaces can lead to a greater reward when it comes to analyzing your building.

A Post from Jeff Hanson.  Thanks Jeff!

Greening up

As the Green Build conference is starting this week, I thought it would be good to talk a little bit about Autodesk’s tools that can help you make your designs sustainable. 

Last week, I was able to take some sustainability training on how Autodesk products can help with make projects Green.  I was most interested in how Revit fits into the mix and took away some interesting information. 

Green Building Studio is a whole building energy analysis tool that allows you to run design alternatives to see how using different building angles on your site, types of glass, or if using low flow toilets will have an effect on the energy that your building uses.  It is a powerful tool that can be used early in the design process so that you can make decisions that have a positive impact of your buildings sustainability.  You can export your building model from Revit right into Green Building Studio and create these alternatives (without changing your Revit model) with a free plug in once you create a account.  Green Building is a web service so there is no software that is needed (minus the Revit plug in).  

Ecotect is a recent acquisition of Autodesk’s.  Ecotect is very cool.  I think that puts it best.  According to the Ecotect website though:

“ECOTECT is a complete building design and environmental analysis tool that covers the full range of simulation and analysis functions required to truly understand how a building design will operate and perform. It finally allows designers to work easily in 3D and apply all the tools necessary for an energy efficient and sustainable future.”

The most interesting thing about these tools is how early in the design process they can be used.  When I was working for Architects, we tended only to think about the energy a building was using near the end of the process.  We didn’t look at energy usage early in conceptual design.  These tools allow you to look at the impact of your design at the earliest stages where simple changes can have the most impact.

You can study the impact of the buildings orientation on the solar gain of your facade quickly.  You can see just what you would need to do to make your building have a zero carbon foot print.  You can perform an acoustical analysis of that large conference room and see how someone at the end of the table would be able to hear the presentation.  It’s not just about sustainability but about understanding the impact of the decisions you are making. 

I really recommend that you take a look at these tools.  They can help you to make a decision that makes your building a little more Green.

Are you Certifiable?

The other day I took the certification exams for Revit Architecture.  There are two exams to take to become professionally certified, a Associate exam and a Professional exam.  I am happy to say that I was able to pass both on the first try without any problems.  It would have been a sad day had I actually not passed the tests! 

The tests are timed, but I had more than enough time to answer and review the questions a second time.  The Associate test is written, mostly multiple choice and the professional exam is practical, meaning that you complete a exercise in Revit and then answer a question about it.  I would recommend anyone that wants to validate their skills with Revit Architecture go ahead and take these exams.  

Since we are so close to AU, I have another reason why is AU cool.  At this years AU you can become certified for Free!!.  Thats right I said free.  I love free things.  (especially food!)

Check out the Autodesk University Certification site for more information by clicking here.

Now for a quick tip

Do you know what the parameter highlighted in the image below does?

It allows a curtain wall to cut an opening in a wall if the curtain wall is drawn on top of the wall.  This parameter is turned off by default in Revit so if you want a curtain wall to create a opening in a wall, turn it on.  This can prevent warnings from appearing when you attempt to draw a curtain wall over a regular wall.

Ask the Experts at AU!

Have you wanted to talk to Autodesk Product Support face to face?  Not to yell at them of course, but to really pick their brain about something Revit Architecture related that you are wondering about?

I'm here to tell you today that you have a chance to do just that.  Are you attending AU? 

This year at AU there will be a Ask the Experts booth on the exhibit floor where you can ask myself, Don Falkowski, and Cedric Vassaotti Revit Architecture questions.  We will be taking your questions live and even showing the answers in Revit.   

This is your chance to ask those questions you have been wondering about face to face.  We will be ready and waiting on the exhibit floor in the booth on Wednesday, December 3rd, from 8 am to 10 am so get their early. 

There will be one more chance on Thursday, December 4th from 11:30 am to 2 pm to  talk to Product Support. This time, will have a product expert from AutoCAD, Revit Architecture, Inventor, and Civil 3D on hand.

AU is always exciting and this year you have a chance to Ask the Experts yourself face to face. So join us at Subscription Exhibit Booth #150.  Enjoy!

Custom Fill Pattern anyone?

Have you ever needed a specific look for a fill pattern and nothing in the standard Revit PAT files fits the bill?  You need a “custom” fill pattern.  So off to the help file you go to find out how to create a custom fill pattern.   You find out you can import a custom PAT file, great news.  Then you look to see how a custom PAT file is created and it looks like some kind of foreign language.

PAT files are simply text files written in a specific way to tell Revit basically when to lift the pen up and place the pen down when drawing the pattern.  The instructions in the text file make up a series of lines or dots we see as the fill pattern.  Without a lot of experience in creating these files, or a lot of time to experiment with trial and error, writing a PAT file “by hand” can be a daunting task.

If you still have AutoCAD (I know, I know), you can use the LSP file downloadable below to help you create a custom PAT file just by drawing what you want it to look like.  The LISP allows you to draw the pattern using basic AutoCAD elements, line, point, circle, arc, etc… in a 1 unit by 1 unit box.  Then the LISP translates what you draw in the box into a PAT file.  Now you can import the PAT file into Revit to create the custom fill pattern you need.

Download HatchMaker.lsp

Remember if you want to use your custom PAT file as a model fill pattern you need to modify the text file to let Revit know it can be used as a model pattern.  Open the PAT file in a text editor and add this line before the pattern definition.

;%TYPE=MODEL

Now save the file.  It is as simple as that.  Now the PAT file can be used to create a model pattern.

This Tip comes to you from the desk of Jeff Hanson.  Thanks Jeff!

Sticky Array

The other day, before I started teaching my class at the Boston Architectural College, a student from a previous class asked me a Revit question.  It took a few minutes and help from another professor (Jeff Hanson, one of my guest posters) to figure it out. 

The problem she was having was that while attempting to arrange geometry in a family, the geometry would not array vertically in the family but would only array in plan. 

Try creating a solid extrusion in a plan view in a family, and then switch to elevation view and create an array that copies the extrusion up.  You won’t be able to do it right away.  

The problem is cause because the solid extrusion is locked to the reference plane on the Ref. Level where you created it.  There is a quick fix to this problem.  You can disassociate the geometry from the work plane.  The trick here is that it is not totally clear where you do this. 

The key is the Edit Work Plane… button.

Once you click this button on the options bar (with the geometry selected) 

You can click the Dissociate button in the dialog box to remove the work plane from the geometry so to speak.  Once this is done just click Ok and now you can array the geometry in elevation. 

A Quick Tip on Memory

Computer Memory is an interesting thing.  It seems like you can never have enough.  Memory with Revit can be a difficult nut to crack. 

Revit uses memory for a variety of tasks.  Often the most memory intensive tasks are related to creating output.  As in, Rendering, exporting, and plotting.  The bigger your project the more need you have to free up memory on your machine before you do these tasks. 

A good way to begin to free up memory is to close any hidden windows that you have open in Revit.  You can do this via the Windows pull down menu.  I ran accross a nice little tip today on another blog that could save you a few mouse clicks and make this easier.  

Check out this post by Mike Hacker from Revit @ Waterman at http://revit-waterman.blogspot.com/2008/10/close-hidden-windows.html 

 

This is a nice way to make Close hidden windows a little easier  and to free up some additional memory on your machine when you need it.