BIM Basics: Know These 4 Things Before Starting Your BIM Model
Do you have a point cloud file that needs further processing and conversion? If you need 2D architectural drawings and/or a 3D BIM model made from your scan data, then these 4 steps will be of great value moving forward.
Below is a comprehensive list of information needed to begin creating the right deliverable for a client.
1) Scanned Structure Information
The first thing one needs to know is who the client is and why they need a 3D BIM Revit model.
Some good questions to ask are:
A. What is the purpose of the project?
B. Why does the client need a 3D Revit model?
C. What value are they looking to get out of a BIM model?
If you are looking to learn more about why this step is important, check out our post 3D BIM Modeling with the End User in Mind.
Next, gather details that pertain to the property itself.
A. What type of property is it?
Commercial building or residential home?
Factory or empty warehouse?
B. What about the size of the structure? In square feet or square meters?
C. Is this a bridge or another type of structure? If so, think in terms of length/height.
To continue exploring why knowing the type of property you are going to model is important, check out our post: Understanding How Varying Property Types Affect 3D BIM Modeling.
2) How Detailed Should You Be?
Right off the bat, the importance of knowing the intended use of the model comes into play. Knowing these 3 pieces of information before starting the project will make things run more smoothly! This is because they affect the entire model.
First, establish the units to be used. There are, of course, two options:
A. Imperial (pretty much only used in the USA)
B. Metric
Then, you will want to know the Level of Accuracy (LOA). What this tells you is the required precision the modeler should use. LOA is more important on some projects than on others.
This brings us to the Level of Development / Detail. Level of Development is an industry term for the amount of detail the model should have. The options are LOD 100, 200, 300, 400, 500. The higher the number, the more detail that is required. This is another reason knowing the needs of your client is so important. You don’t want to spend hours modeling the very fine details, when the client may only need basic shapes.
If you are interested in learning more about LOD, check out our post: BIM Basics: What is LOD?
3) Elements To Be Included
After establishing the units, the LOA, and the LOD, it is time to determine which elements of the structure need to be included in the model. Again, knowing the end-user of the model is of utmost importance.
The first question to ask is whether the model will include interior or exterior elements. Most often the model will include both but knowing for sure will save time.
From there, you can determine which elements of the interior or exterior to model. Below you will find the checklist that our team uses. The list is not exhaustive but is a good starting point.
Architectural Elements
☐ Floors
☐ Walls
☐ Ceilings
☐ Roof
☐ Windows
☐ Doors
☐ Curtain System
☐ Stairs
☐ Railings
☐ Ramps
☐ Cabinetry
☐ Lights
☐ Fixed Elements
☐ Dimensions
☐ Room Tags
Structural Elements
☐ Columns
☐ Beams
☐ Trusses
MEP Elements
☐ HVAC
☐ Ductworks
☐ Plumbing Fixtures
☐ Piping System
☐ Cable Trays
☐ Communication Devices
☐ Security Devices
☐ Lighting Fixtures
☐ Electrical Panels
Exterior Elements
☐ Parking Spaces
☐ Railings
☐ Sidewalks
☐ Ramps
☐ Planting
☐ Lighting
☐ Stairs
☐ Paths
☐ Furnishing
If you can establish the elements to be modeled upfront, it will give the modeling team a great idea of where to start. Note that LOD can directly affect which elements the team is modeling. This comes into play most often with MEP elements.
If you'd like to learn more about our process for identifying elements to be modeled, check out our other post: BIM Basics: Possible Elements of a 3D BIM Model
4) Determine The Deliverables
The final step before beginning to work on the model is to determine what the final output will be. You can get a ton of useful information and documentation out of the 3D Revit model, so it is worth establishing what the client needs upfront.
Often clients need 2D documentation to go along with the 3D BIM model,especially when working with architects. These documents can be taken directly from the 3D BIM model. Some examples of these 2D drawings are:
A. Floor Plans
B. Reflected Ceiling Plans
C. Electrical/Mechanical Plans
D. Interior/Exterior Elevations
You will then want to determine the software version. We mainly work in Revit and AutoCAD. If you are familiar with Revit, you know that Autodesk releases a new version every year. The updates are great, however, the files generated are not backward compatible. This means you cannot load a Revit 2021 file into a Revit 2019 without having any issues.
So, the takeaway here is to know what version of software the client and end-user will be using. Then, model the deliverables inside of that version.
For a further dive into deliverables, check out our related post: BIM Basics: 2D & 3D Deliverables
There you have it, 4 Steps to take before starting any 3D Revit modeling project!