The Quest for Speed in Revit
As contractors rush headlong into the Revit world to work alongside their architectural and engineering counterparts, one of the biggest hurdles to overcome is the speed of processing.
One of the primary reasons to use Revit as the model platform is the abundance of data held within the model. Whereas AutoCAD can provide a pictorial representation of the project, Revit provides an intelligent functioning model of the project. As a result, Revit models, as they contain so much more data, are typically many times larger than AutoCAD models. This is because Revit models are typically complete buildings rather than just AutoCAD ‘areas’. Revit models in the gigabyte size range are not uncommon.
When dealing with projects of this size, speed becomes a significant problem. Regardless of the processing power, RAM, and video capabilities of a computer, a gigabyte Revit model is going to present problems to productively work in.
The Copy/Monitor Function In Revit
Luckily, Revit has a built-in tool to deal with this situation - Copy/Monitor. Copy/Monitor (C/M) allows the user to cherry-pick components out of an existing model, copy them into another model, but also maintain a link back to the original so if it is changed, the user is notified and can act accordingly.
Revit models typically contain links. These are broken up into architectural, structural, engineering, etc. These links may be further broken down into, for example, engineering discipline links such as mechanical, plumbing, electrical, etc. Not everything in the model is important all the time. Unloading a link reduces the amount of data that Revit has to handle but loses EVERYTHING in the link. C/M is a tool that allows important components in the link to be maintained even when the link is unloaded.
C/M also has an additional benefit of allowing the user to start from their own template file (containing schedules, filters, view templates, title blocks, etc) that they use rather than having to recreate them in every project/model.
I’ve always recommended, regardless of the project or how a contractor intends to tackle it, that it is well worth spending time with the initially supplied models on a project to determine what you have, what level have they been developed to, what is in each model within the project and how the project is expected to progress. Time spent at the front-end of the project pays for itself many times over during the life of the project.
A Revit template is essentially your toolbox; a starting point for your contribution to the project. You can always add to this toolbox during the course of the project, but if there is a particular tool to use on every project, this should be in the template. Schedules, View Templates, Filters, Title Blocks, Annotation Tags, etc, should be part of the template.
Two Things Frequently Overlooked are Levels and Views
Levels and Views are project specific so having them in your template is not really useful. Revit requires a minimum of one Level in a project so they can all be deleted but, a useful method, is to rename the one Level in your template as something unique and easily identifiable so that when you C/M the actual project Levels, you can easily identify and delete the one from your template. Naming the Level - DELETE ME isn’t such a bad idea.
Levels in a project are typically very important. So step one, after creating a new project based on your template, is to link to the model with the best set of Levels, typically the architectural model. If the Levels you need are spread across multiple models, I would suggest linking and C/M each model separately.
Copy/Monitor (C/M) is a very powerful though potentially quirky tool. It resides on the Collaborate tab of the Revit menus. You need to be able to see the components you intend to grab, so a suitable View is necessary. For Levels, I always recommend an Elevation View.
To use Copy/Monitor, get to a suitable view, (Elevation in this case), and then use Copy/Monitor -> Link. Select the Link for the model containing the Levels. Revit will now present the C/M context menu from which you need to choose ‘Copy’.
Typically, multiple Levels are required, so rather than repeating C/M for each Level, you can choose the ‘Multiple’ box and then either drag a window around the complete model or select all the Levels you require.
If you do use the window selection, use the ‘Filter’ icon to deselect other things. From an elevation view of the architrave model, Levels, Floors, and Grids are all fair game. Avoid Walls and any Equipment from this view. Once you have made your selection, use the ‘Finish’ on the selection menu (NOT the ‘Finish’ with the green checkbox).
Revit will make copies of your selection and create links between your model and the linked model (resulting in the ‘link’ icon being placed beside the components). To complete the process, you must return to the ‘Copy/Monitor’ tab and select the green check mark Finish.
The next step is to create Views for the Levels. As there are now multiple Levels in the project, I typically find my template Level (DELETE ME) and delete it.
To create Views from the C/M Levels, from the View menu choose Plan Views -> Floor Plans. This will present a list of all of the Levels that do not have Views. Using the Shift key you can select all the Levels on the list and hit ‘ok’. You will see in the Project Browser Views for each Level have been created.
The next step will probably be relevant to walls. You don’t typically need all the walls in a project, just the ones around where you are working. Using one of the floor plans just created, find an area where the walls are important. Again, start the Copy/Monitor command, select the link, choose Copy and check the Multiple box. You can now drag a window around the walls you are interested in (eg. Electrical room).
Use the filter icon to ensure you only have the walls selected, use the selection Finish and then the Copy/Monitor Finish. Repeat as necessary to get all the walls you need. You can always come back at a later time and add more components to your selection. In the same way that trying to work in a large Revit model will slow things up, Copy/Monitoring too much can have the same effect. Be selective, maybe consider using multiple models yourself (eg. first-floor model, second-floor model, etc).
With the Levels, Floors, Grids, and Walls from the architectural model in place, you can now unload that model (from Manage Links) and then Link in the next applicable model, maybe the Mechanical model. You can now use the same technique to Copy/Monitor any relevant equipment and/or devices. Using Copy/Monitor to select the same thing (eg. walls) from two models is not normally a good thing.
With all the relevant components from the separate models Copy/Monitored, you can unload all the links and you are left with just what you are interested in, a much smaller model along with Revit monitoring your components against those in the originals so if they are moved, edited, deleted, you will receive a ‘Co-ordination Review’ warning message alerting you to a possible problem.
Copy/Monitor isn’t always the answer, or applicable, but it is a very powerful, and typically under-utilized tool, in the quest for speed in a Revit project.