Generative Design and BIM Design
Contributors: Diego Ocampo (Preliminary Research)
Generative Design and BIM Design
The basics about BIM
Building Information Modeling (BIM) is a digital representation of physical and functional characteristics of a facility. A BIM is a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle; defined as existing from earliest conception to demolition
The goal of BIM is to centralize all the information on a single database of information.
That database of information is usually data associated with different components of a 3D model of the building, so BIM is nothing else than sharing the same digital 3D models of a project between every possible team that will take part in the different stages of the lifecycle of a building, from the design stage, to the different maintenance needs until the very deconstruction of the building.
Those 3D models include data that define physical and functional characteristics of each component that is part of the building, and more importantly, defines relationships between different components in a way that if a property is changed in one of the components the model will automatically reflect how any other component is affected.
So if a project has well defined BIM models of a project, in a BIM designing software like Revit, not just the designers and architects can visualize the project in 3D (or even walk through in VR) but every other team that needs to interact with the project can use the exact same models to do their part before the building is deployed (engineering work, lighting design, calculate energy consumption, evaluate structural integrity) and after the building is deployed (maintenance, renovations, deconstruction).
Also, once you have your BIM project with the 3D models properly documented, you can export all sort of traditional and not so traditional documents:
The basics about Generative Design
Generative Design is using AI techniques to suggest a range of possible designs for a piece of an architectural or mechanical model. For this AI-supported iteration process you as a designer will give a set of constrains and parameters (areas that can't be modified because they are attachments to other pieces, different forces being applied into the piece, etc.), goals (minimize mass, maximaze stiffness) and manufacturing process (depending on the kind of 3D printer or other processes you use to actually manufacture the piece).
The software will generate a range of possibilities, not just in shape but also in materials; and you could not specify one single manufacturing process but instead leave it open to study what are the possibilities with each of those manufacturing processes.
The pieces generated this way usually have a very organic shape
Software for BIM design
The most widely used is Revit, part of the Autodesk suite https://www.autodesk.com/products/revit/overview
and it’s bigger competitor is Tekla https://www.tekla.com/
Revit uses something they name “BIM 360 Design” which is their solution in the cloud for everybody in the team to coordinate a BIM project, using Revit as the design software.
DRAFT: on the difference between Inventor and Revit https://forums.autodesk.com/t5/inventor-forum/revit-vs-inventor-design-methods/td-p/3294147
Software for Generative Design
Autodesk Fusion 360 vs Autodesk Inventor
Fusion 360 is a cloud based solution (can be used anywhere and works on Windows + Mac), inventor works on Windows only. It seems as if with Fusion 360 you can do basically all it can be done in Inventor but the workflow is a bit different. Also for very complex projects it seems people still prefer Inventor over Fusion 360. Here are some comments on this:
“Inventor and fusion have 2 different workflows/design philosophy. Inventor is like solid works - separate files for parts, assemblies... Fusion - bodies, components all whacked into one entity. Its like designing parts from assembly level. Personally I use both, depending on what I do. Quick parts for printing - fusion, machines with multiple parts, moving commoners and fixings, screws... - Inventor.”
Fusion 360 offers free use for personal / hobby use with some limitations. So it is nice to learn for free. But the free option doesn’t include generative design
Workflow with Inventor for generative design
Inventor is used for all the design process. Fusion 360 is used for the generative design process.
A simplified workflow is this:
Choose the piece of the model that you would like to see alternatives for using generative design technology.
Locate all the assembly points and decide what is the geometry that has to be preserved exactly as it is because it has to fit with another piece of the model.
Now analyze what are the “obstacle geometry”, that is the limits within which the piece needs to stay, so this will be geometry we generate to tell the generative process what has to be avoided.
Configure the generative simulation
Run the generative simulation to see all the possible designs.
More in detail workflow:
Preserve geometry and obstacle geometry. This can be done either on Inventor first and then selected in Fusion 360 or it can be also done directly in Fusion 360. For example
Generative simulation parameters
We setup all our load cases. These are the conditions that the piece will face in real life: gripping force, gravity, etc. We can have several cases added, for different real life situations that the piece will have to deal with
Manufacturing types and materials
He are we establish:
Objective and limits. This indicates your mayor goal when the AI goes through possible generative options. For example maybe you want to minimize the mass used for the piece
Then you select all the possible manufacturing characteristics, this is because the piece design will have to comply with how your manufacturing process will work to make sure the piece can really be built with your manufacturing process.
Explore and decide
We explore all the options generated and we make a decision based on the cost vs performance tradeoffs. Filters can be used to focus on specific materials, results, or manufactoring processes
Generative design creates solid editable CAD geometry that we can adjust, validate and postprocess. Then we can send it back to Inventor to use integrating it with the rest of the model.
The BIM dimensions (4D BIM, 5D BIM, etc.) is a way of describing how extensive the BIM project is, adding more data with each new dimension. However there is no full consensus on definitions beyond 5D, but here are some general ideas:
3D is the modeling information. 3- dimensional (x, y, z) geographical structure.
4D includes time: timeline, scheduling and duration
5D includes money: cost estimates
6D sustainability and energy
7D operations. Holistic facility management information for entire lifecycle
More information here https://www.united-bim.com/what-are-bim-dimensions-3d-4d-5d-6d-7d-bim-explained-definition-benefits/ and here https://en.wikipedia.org/wiki/Building_information_modeling#Purposes_or_dimensionality
Revit + Inventor
Revit is not a replacement for Inventor. They are two different tools
Inventor is software for a more specific design process that usually involves mechanical design and therefore models not just the final look and dimensions of a component but absolutely all the little pieces and moving parts involved on achieving a movement or change
Revit is the central project where all the teams from different disciplines can go and look at 3D models of the building but each of the components do not need to go down to the “bolt and gear” level.
For this reason,
Revit for BIM design
Working with Revit and BIM 360
Revit is the actual tool to build and maintain BIM models. BIM 360 is a cloud service offerred by Autodesk for sharing and keeping in sync those models in a way that anybody in the team, from anywhere, can always get the latest version.
I came across with other solutions for BIM design but I discarded them because it seems that Revit and Tekla are taking over completely as the choice for BIM design. However one that came up several times is AchiCAD https://graphisoft.com/solutions/products/archicad which has its own twist on the BIM approach, they name it “OpenBIM”. And there are some discussions about how ArchicCAD might be a more approachable solution for residential projects, here is a relevant recent discussion on this https://www.reddit.com/r/architecture/comments/hi06jt/archicad_vs_revit/
Here is a video of an interesting big project built on ArchiCAD https://www.youtube.com/watch?v=D-tue-ZPThY
Project video link: