Revit MEP

Revit MEP

Wednesday, January 23, 2008

IFC Import to Revit MEP

Revit MEP provides Industry Foundation Classes (IFC) import based on the latest International Alliance for Interoperability (IAI) IFC 2x3 data exchange standard. (If you import a file that uses an earlier standard [IFC 2x or 2x2], Revit MEP supports the format and imports it properly.)

When you import an IFC file, Revit MEP creates a new file based on the default template.

You can load your own IFC class mapping files and override the categories and subcategories for imported IFC objects.

Make sure you import the geometric data needed for the Revit MEP capability that you plan to use.

To import an IFC file:

  1. Click File menu => Import/Link => IFC.
  2. In the Import dialog, navigate to the IFC file to import.
  3. Select the IFC file, and click Open.

Revit MEP creates a new file based on the default template.

Revit IFC Export to AutoCAD MEP

You can export Revit MEP building modeling information to the Industry Foundation Classes (IFC) file format.

About the IFC File Format

The Industry Foundation Classes (IFC) file format was developed by the International Alliance of Interoperability (IAI). IFC provides an interoperability solution between different software applications. The format has established, international standards to import and export building objects and their properties.

IFC improves communication, productivity, delivery time, and quality throughout the life cycle of a building. It reduces the loss of information during transmission from one application to another, with established standards for common objects in the building industry.

Revit MEP and IFC

Revit MEP provides IFC import and fully certified export based on the latest IAI IFC2x2 data exchange standard. When you export a Revit MEP building information model to IFC format, the information can be used directly by other building specialists, such as structural and building services engineers.

For example, building information models developed with Revit MEP are saved to the RVT file format. You can export the building model using the IFC format to an IFC-certified application that does not use the RVT file format. The drawing can be opened and worked on in the non-native application. Similarly, in Revit MEP you can import an IFC file, create a RVT file, and work on the building model in Revit MEP.

IFC uses architecturally meaningful containers to describe real-world building objects. Those containers include parameters that have meaningful values. Many standard Revit MEP elements have corresponding IFC containers. These do not require any specific user action to export them. (For example, Revit walls export as IFCwalls.)

To see how to import this IFC file into AutoCAD MEP, see my blog at

Monday, January 21, 2008

Worksharing Monitor for Revit MEP 2008

If your Revit MEP is on subscription, you can download the new Revit 2008 Worksharing Monitor Extension from your subscription website.

The Worksharing Monitor facilitates the use of Revit software in a worksharing environment, in which multiple people work on one project. For workshared projects, the Worksharing Monitor answers questions like the following:
  • Who is currently working on this project?
  • Is my local copy of the project up to date?
  • When will my Save to Central operation finish?
  • Has my request to borrow elements been granted?
  • Are any issues interfering with my work on a Revit project?

NOTE: The Worksharing Monitor is not useful for standalone Revit projects, which do not use worksharing to divide the work for a project among several people.

To install and run Worksharing Monitor for Revit 2008, you need to have at least one product from the Revit 2008 product family installed on your computer. You must have a 2008 version installed, with SP2 or SP3 (also known as WU or web updates). Available products include:

• Revit® Architecture 2008, SP2 or SP3
• Revit® Structure 2008, SP2 or SP3
• Revit® MEP 2008, SP2 or SP3

Tuesday, January 01, 2008

Managing RAM Memory in Revit

A friend of mine (Tony Isenhoff of Eppstein Uhen) and I were discussing how RAM is utilized by Autodesk applications. As you work in your application, RAM is used, and in many cases is not returned to the OS when it's no longer needed. The problem arises when you start to reach the 2 GIG limit for a Process in 32 Bit Windows or you simply start to run low on memory.

But if you simply Minimize the application window, wait a second or two then Maximize your application, the RAM is given back and you can continue working.

Tony confirmed this in Revit by opening one of their larger projects using Revit Architecture, and opened 3-4 views, and watched the memory usage go up, then minimized. Below are the results:

Before minimize:

After minimize:

I also confirmed this in Revit MEP and AutoCAD MEP.

So when working in Revit and you get a message that you're running low on memory, try minimizing the application window!

We always knew that having multiple views open can also affect performance, but we were pretty surprised at actually how much RAM is used.

One view open: 784,380 k
Two views open: 817,520 k
Three views open: 847,220 k
Four views open: 872,896 k

So closing views that are not being used is also very important.

Coordination Review

Coordination review is the process by which models are resynchronized to see if there are changes to the linked architectural model. So if the level to level height changes, or levels are renamed, or rooms are deleted, Coordination Review will show you the changes that need to be made. When the file is opened, the user will be prompted of the architectural changes that were made, and show them to you.

To see the coordination issues, select Coordination Review from the Tools menu, and select the appropriate linked file. When the Coordination Review window opens, the issues will be listed, and you can select the appropriate action. You will rename, move, and delete elements in your model to follow suit with the architects linked file. To copy newly added rooms, you must use the tool in Copy/Monitor. You are not notified when new rooms are added, so make it practice to open Copy/Monitor, and click Copy Rooms when a updated model is received.

Element Borrowing vs. Workset Ownership

In Revit MEP, it might be easier to work using Element Borrowing Mode rather than using Worksets. Worksets create an environment where users retain ownership of entire worksets, and permission must be granted for other users to make changes to elements in that workset. For example, if a user owns the MEP Equipment workset, and a user needs to relocate a piece of equipment, or even just change the Mark of the equipment, the user must first request permission in Revit, notify the owner that they are requesting permission, and the owner must grant permission. But by using ‘Element Borrowing Mode’, elements are borrowed ‘on the fly’, and provides a much more fluid workflow.

There is no setting to use Element Borrowing Mode, it is just a matter ensuring that the appropriate worksets have no owner. With no owner, the elements in the workset are borrowed automatically as needed. Clicking Save to Central automatically relinquishes ownership of the borrowed element(s) so that another user may make modifications as necessary.

In Revit MEP, users should be aware that even though they are not directly modifying an element, they may end up borrowing elements unwittingly. As users work in the model, they may be inadvertently borrowing more and more elements, and preventing others from doing the same. This is because Revit MEP not only uses elements, but uses elements that make up systems. Systems can contain multiple elements. Whenever a change is made to an element that is part of a system, the system information must be pushed upstream to keep everything synchronized. So a user modifies the flow at a diffuser, the flow information is pushed through the duct system as far as it is connected. When this happens, that user not only borrows that diffuser, but also becomes borrower of all the other components upstream of that component. If another user were to attempt to modify the flow of any of the other terminals at the same time, that user would receive an Error message, alerting that the owner of those elements needs to save to central. This can also happen when multiple VAV boxes are connected upstream to a common air handler. If a user were to modify the flow on a diffuser in one area of the building, the flow from the ductwork all the way back to, and including the AHU would be borrowed, which would prevent any other users from making changes to any elements, even though the user may be working on a completely different portion of the building.

One solution to this is to ‘break’ the ductwork of two systems before an AHU and create 2 separate systems and thereby separating the data that users will be updating to a full system. Now you have two systems that don't push information to each other which allows two users to work on them at the same time without having to borrow elements. Use this option to create this gap to control how far information will update.

Strategically segregating the data in the model can help ensure that multiple users can work side-by-side. When all updates have been made, the ducts may be easily stretched back together to complete the system.