What are the principal advantages of using a single building information model of the existing conditions as the foundation for modeling proposed additions or renovations?
- Why not create a separate model for the new proposed design?
Using a single BIM model for existing conditions (as the basis for modeling proposed additions or renovations), rather than usings separate models, can significantly enhance project outcomes, for several reasons:
- The existing conditions BIM is an accurate and up-to-date representation of the building/site. This ensures that the proposed additions or renovations consider the existing context, consequently helping to prevent clashes/conflicts with the current structure, utilities, or surroundings. This means that the proposed design can be seamlessly integrated into the current environment, ensuring that the new elements fit well with the existing structure. I experienced this when duplicating the Y2E2 site plan in order to add/extend the structure precisely (for example when placing new walls aligned with the old ones).
- With one BIM model, it is easier to visualize the impact of the proposed design changes. For this purpose, I placed two versions of the 3D views for comparison in the assignment. One shows the completed building, and one shows the demolition plan, highlighting in red all the changes that the old building would encounter in the project.
- A single BIM model enables clash detection and coordination between existing and proposed elements. This helps identify and resolve conflicts early in the design process, thus reducing the probability of costly issues during construction.
- In terms of management and productivity, having both existing and proposed design models in a single BIM helps all the stakeholders (designers, architects, contractors, etc.) with better collaboration and decision-making, as they can easily compare the current and future designs, evaluate the impact of the proposed changes, and consequently make informed choices.
To conclude, creating a separate model for the new design (additions and/or renovations) can lead to several problems, like lack of current context, clashes, lack of coordination, increased efforts and costs, and lack of collaboration among stakeholders. Therefore, using a single BIM model becomes the preferred approach in nowadays construction projects.
What are the principal advantages of using a single building information model of the existing conditions as the foundation for modeling several proposed design alternatives for a portion of the building?
- Why not create a separate model for each of the design alternatives?
Using a single BIM of the existing conditions as the foundation for modeling several proposed design alternatives for a portion of the building is the best approach to follow rather than using separate models for each of the design alternatives.
- First of all, because a single BIM ensures that all design alternatives are based on the same existing data, thus maintaining consistency throughout the project.
- Most importantly, using a single BIM saves the designer a lot of time by avoiding redundant modeling work for common elements. In this assignment, I proposed two options for the existing façade of my new proposed design. If I had to model again twice the whole building façade it would have cost me at least one extra day of work, and it would have led to many inconsistencies between the design options (for example, slightly different wall lengths, different wall joints, etc).
- A single BIM model saves money in terms of resources allocated (designers that do not have to model redundant elements).
- With a single BIM model it is very easy to compare and explore all the different design options, especially in complex projects. With Revit in fact, one can simply select the preferred design option configuration and place its 3D view in a sheet. The client can then easily visualize the impact of all the different design options, as placed all on a single sheet. I attach here a cropped example from my project for better clarity and visualization:
To conclude, creating separate models for each design alternative can lead to redundancy, increased efforts and costs, complexity in managing changes, challenges in clash detection, difficulties in comparing alternatives, and inconsistencies (very similarly to the precedent question). Using a single model for existing conditions and design options is then the best approach to use.