Thursday, March 11, 2010

Accessing Project Parameters in Multiple Schedules

Thank you Domenic Serravite from IBI Group for discovering this undocumented feature!

You can access Project Information parameters in any schedule. For instance if you want to have a factor(coefficient) that is used in many different schedules and formulas this is the way. We will use unit planning as an example. You will want a Mass object with floor faces to start.

Manage-Project Settings-Project Parameters-Add
Name: Average Unit Size
Group Under: Identity Data
Type of Parameter: Number
Category: Project Information

Manage-Project Settings-Project Information
Fill out the new parameter Average Unit Size to a factor like 1000. This represents 1000 square feet.
Make a Mass Schedule
Include Gross Floor Area
Check the Include Elements in Linked Files box

Drop the list down to display Project Information

Average Unit Size will now be available
Make a calculated value called Number of Units
Put this formula in: Gross Floor Area / 1 SF / Average Unit Size

Now you can control centrally important information from one place. This can be done in Room and Area schedules as well.
Autodesk is aware that this is confusing and will sumbit it to the development team.

Wednesday, March 03, 2010

Coordinates, Base Points, Surveys, Linking and Other Confusing Things - Part 1

If you browse through the forums, blogs, how-to videos and books you will find a wealth of information on the above titled subject. And it's all conflicting. It's just about the most confusing subject you will encounter in Revit. I will now add my voice to the many others. The method I'm proposing can be boiled down to a common point which is graphically represented in all files. You will then line everything else up based upon that.

The architect must set this up BEFORE anything is done in Revit. No modelling, importing, linking, not anything.
Step 1. Set up the AutoCAD
AutoCAD survey drawings usually have 3D contours and 2D drafted information. The 2D stuff is at 0 Z elevation, the 3D is at it's actual height off of Sea Level. The 0,0,0 or Origin can be anywhere and sometimes it relates to something but sometimes not. We will be changing this.
Save as.
Give new name.
Move everything so the 0,0 is at the bottom left (don't adjust the Z). This could be at the property line intersection.
Make sure there is nothing outside of a 10 mile radius sphere from the 0,0,0. That means you will need to take a look in the Z.
Draw a circle on an individual layer at 0,0,0.
Rotate these to Project North. Make sure there is a North Arrow visible.
Break this file into two files, one with 2D plan info and the other with contours. You can use the wblock command or saveas.
Of course, you should audit and purge the AutoCAD file as well.

Step 2. Not in Revit yet...

Get the longitude/latitude information relating to the AutoCAD site file.
Open Google Earth and go to the address. Find the longitude/latitude of the corner of the site that corresponds with the 0,0, write it down.
The Google Plugin also works great as well. It will import the location to Revit's 0,0,0 as well as draw some Reference Planes and bring in a flat image. It will also give you the true north.

Step 3. Revit Architecture

Revit has a 10 mile diameter of where you can draw or even import. You cannot have anything outside of that.

Manage Place and Locations will assign the Longitude/Latitude numbers to your Revit 0,0 (Origin)
Revit 0,0,0 is found by default at the centre of the elevation markers. It's also the default location of the Project Base Point and Survey Base Point. The Revit origin can not be moved.

Make a view called AutoCAD Site Plan.
Import the 2D AutoCAD. Origin to Origin. Current View Only turned on. You cannot change Revit's origin. The origin can be found at the nexus of the elevation markers in plan. This point is dead centre on your screen when you start from a standard Revit Template.
Then Import the 3D AutoCAD Contours, Origin to Origin. Current View Only turned off. You won't see this file yet, it's above your view.
Go to elevation, move the contours down to level 1.
Go to the site plan view.
Confirm that your Survey Base Point(triangle with an x) is at the centre of the circle you drew in AutoCAD.
Click on the Project Base Point (a blue circle with an x). Click in the 'Angle to True North' and type the difference between your project north and the true north. You may have to type a negative in front of the degrees to get the expected results.
The Project Base Point and Survey Base Point will be in the same place. That's fine.
You may also want to draw two Reference Planes based on the centre of the AutoCAD circle which is also the origin. Name them something logical.
Adjust your elevation markers and datums to focus on where your building will be.
Start drawing grids and modelling etc.
Step 4. Other Linked Revit Files...
Start your new Revit Structure or MEP file.Very first thing you do is link the Revit Architecture file (which we just setup) Origin to Origin.
Check that the Z has come in correctly.
Adjust your elevation markers and datums to focus on where your building will be.
Draw Grids and Levels over top of the linked Revit Architecture as needed.
Start drawing grids and modelling etc.
About Exporting back to CAD...
When exporting back to AutoCAD the origins of both AutoCAD and Revit will line up as long as you have used the default location of the Project Base Point.

Monday, March 01, 2010

Book Review: Revit 2010 Family Standards and Best Practices

Revit 2010 Family Standards and Best Practices (Take the Dysfunction Out of Your Families)
By Shawn Zirbes & Integrated Content Solutions, Inc.
205 pages
Right on the front cover the book states that ICS is a Premier member for Autodesk Seek. I don't want to start off negative but as of today the content on Autodesk Seek is not something to brag about.
Autodesk Seek is a good framework for the distribution of content. That's why it's so disappointing that many of the families are useless. But this isn't a review of Autodesk Seek.

This book has lots of good tips, tricks and best practices. The more unique tips are highlighted in red. The MEP connectors section is quite well developed. There are good naming conventions proposed throughout. Family testing methods are explained (makes me wonder if they're used at Autodesk Seek?). In the beginning of the book there are some nice graphic scenarios on Sketch Mode and Masking Regions. It seems that this tales off and some chapters are very sparse. I was looking forward to the formulas chapter but was disappointed to find that it was virtually just cut and pasted from the Revit Families Guide with no extra examples, tips or otherwise. Overall I would say that this book takes the best segments from the Revit Families Guide and Revit Model Content Guide, adds a few extra tips and organizes them into a tidy little pocket guide.

Here's a link to the Amazon page: