I once heard a term for Revit called “dog piling”. This is where people put a bunch of families outside the building as kind of a library to copy from since revit doesn’t really have tool pallets of any sort. Why would a dog need to pile bones if he could right click and create another one instantly?!
In this writeup I am going to discuss some of the lessons I have learned over the past few years about managing MEP content on a large project. Some of this content I created from scratch and some I downloaded from manufacturers. On this project I was in charge of managing the HVAC and Plumbing content.
Creating content from scratch:
Custom content will need to be created since there are still manufacturers that are not providing content. This will probably always be an issue with BIM especially if the project requires custom equipment. Autodesk has a good tutorial on this but it’s pretty outdated. It would still be valuable to go through it and get the basics so you can build on it. There are also other sources: blogs, youtube, etc.
Link to Autodesk Revit MEP Family Tutorials:
Downloading content from manufacturer’s:
There are many manufacturers providing Revit families these days. I have a list in a previous blog post with links to all the website of manufacturer’s providing content. (The link to AUGI is probably more up to date)Some manufacturers have better content than others but it is often easier to start with these than it is to start from scratch.
Below are a few things to watch out for with families in no apparent order:
*AIA-E202: Some projects are required to be modeled to a certain level of detail based on this document.
*Level of detail: Families with too much detail can drastically slow down a large model. Especially if you have a hundreds or thousands of instances. On small projects this is not as big of a deal. Find a balance between modeling all the details of a part or just modeling the general shape. Also, round shapes take more PC power to calculate than square shapes!
*Display in Medium vs Fine Detail: Sheet views are typically set to Medium Detail. If the manufacture has not taken this into consideration then it might not show the proper symbol on plan (Valves, Diffusers, Lights, etc.)
*Connector properties: Test the duct and pipe flow to make sure these are calculating in the right direction. Also that they are on the right system. (see image)
*Flow Arrows: I put flow arrows on equipment that only show up in fine detail so the designers don’t put them backwards. This way the will not plot on the sheets that are set to Medium Detail. (see image)
*Maintenance Clearance: I used the same Mechanical Equipment Sub-Category name for all my maintenance clearances. This way we only had to uncheck one place to turn them all off in Visibility Graphics.
*Hosted vs Non-Hosted: The big hosted vs non-hosted debate saga continues…. My personal preference is non-hosted and if we have to use hosted use a reference plane over a linked surface. There are many sources on the internet where this issue is debated heavily so go there since I’m not looking to get involved :)
*Navisworks: If you are using navisworks keep in mind that each extrusion becomes an element that is clashed. For example, if you have a pendant light family that has 4 horizontal extrusions for the light shape you will get 4 clashes if its intersecting a duct. There might be a way to filter these out in NW.
*Materials: Are you going to be rendering this model? If so you might need more detail in your families and materials applied so the renderings turn out better.
*Model Category: Depending on how you are controlling visibility and how you want the family to work the Model Category could be pretty important.
*Type vs Instance Parameters: Be sure to think through where you use type and instance parameters. Some of the manufacturers might not do this how you will need it in your project since it can vary.
i. Type Catalogs: More family types will make your working model larger. Only bring in what types you need!
Connector Properties and Flow Arrows
I decided it would be a better idea to create a blank project and set up a view where you can layout the different families and family types. The purpose is to test families before they are distributed to the team and inserted into the project models. You can put all the families for the project into one test model or split them up by discipline depending on project size and the amount of content.
It is probably a good idea to use the same template used for the project models rather than the out of the box template.
HVAC Test Model
Plumbing Test Model
Things to test:
*Display at different detail levels on plan, in section and 3D
-Medium Detail is typical for sheet views
-Fine Detail is typical for working views
*Parametric families should flex properly
*System connector properties calculate flow and be on the right system type
*Hosted/Non-Hosted families host properly
*Tags display properly – I input some of the type parameter data the tags are reading before I distributed them. For example diffusers and the GRD schedule.
*Setup a small room with a ceiling to test hosted families if you are going this route. Otherwise reference planes will work. (ex. diffusers, receptacles, etc)
Create Library documents for designers:
*Create PDF’s of the different families and family types for the engineers to reference. This is helpful on a large project with hundreds of different families. Sorting through them in the properties pull-down can be a daunting task. If they have a PDF to reference they can go to the project browser and find the type name to insert. (see image)
*Be sure to communicate to the designers that they should not change Type Properties without notifying you!