Managing Renovation Interventions with BIM: Yellow and Red Method

In renovation projects and design variations, one of the key needs for designers is the ability to produce drawings that clearly compare the existing condition with the proposed design, or alternatively two different project scenarios.

This requirement drives the need to efficiently manage, streamline, and optimize the entire workflow involved in developing renovation projects and design variants.

In this context, we refer to architectural design software that offers tools for dynamically comparing the “existing state” and the “project state,” typically managed through the so-called “yellow and red method.”

BIM Renovation Mastery

Why BIM is Essential in New Construction and Renovation Projects

The essence of BIM lies in its ability to manage complexity. In a building renovation project, one constantly faces unforeseen issues and the need to coexist the existing structure with the new one. Unlike traditional technical drawing, which is limited to two-dimensional graphic representations, the BIM model integrates geometric, structural, energy, and temporal data, allowing the designer to anticipate interferences that, in the past, would only have emerged during the execution phase.

Overcoming Critical Issues in Surveys and Variants

One of the most tangible advantages concerns the management of ongoing variations. We know well that a renovation site is a living organism: a demolition may reveal a load-bearing structure different from the one hypothesized, forcing an immediate revision of the project. In a traditional workflow, this entails a slow and fragmented rewriting of plans, elevations, sections, and metric calculations, with a very high risk of human error.

With the adoption of BIM, every change made to the model is instantly reflected in all technical documentation. One no longer “draws” a line but manages a parametric object that carries information about materials, costs, and performance. Therefore, this approach guarantees:

• millimeter precision – integration with advanced surveying tools such as point clouds;
• reduction of extra costs – early identification of clashes between systems and structures (clash detection);
• transparency towards the client – a clear and immersive visualization of the finished work and intermediate stages.

Manage interior design and renovation in a single 3D model

Traditionally, interior design and structural or distribution renovation were treated as separate phases, often managed with different software or separate files. This siloed approach is the main cause of graphical inconsistencies and delays. The adoption of a BIM-oriented approach allows for the convergence of the macroscopic vision of the building with the microscopic detail of furnishings and finishes in a single design environment.

The importance of modeling the “As Built” and “Proposed” states

The true strength of managing in a single model lies in the ability to dynamically overlap the as-built (existing) state and the proposed (new configuration) state. Through the use of temporal filters and comparison tools, the software allows for real-time visualization of demolitions and constructions.

This is not only useful for bureaucratic purposes for the automatic production of the “yellow and red” drawings, but it is essential for interior design. Knowing exactly where existing columns or load-bearing pillars are while designing the kitchen or bathroom avoids positioning errors that would otherwise only be discovered during installation. The designer can thus test infinite distribution variations, instantly verifying the impact of each choice on both the structure and the final aesthetics.

Advanced visualization and material selection

A unique 3D model also serves as a powerful communication tool. Thanks to the ability to apply realistic textures, manage lighting, and insert design objects directly into the BIM model, the professional can offer the client an immediate immersive experience. It is no longer about showing an abstract plan but about allowing the client to walk inside their future home, obtaining additional benefits such as:

• data consistency – every piece of furniture or material inserted in the model is not just a “drawing”, but an object that contains information, for example, about costs and suppliers;
• document automation – furnished plans, detailed elevations, and material schedules are generated and extracted directly from the model, ensuring that what is displayed is exactly what will be built.

How to Document Project Variants and Change Orders with BIM

In the context of a renovation, managing ongoing work variants and change orders often represents the most critical phase for the profitability and timeliness of a project. Without a structured methodology, the risk is to lose traceability of changes, leading to disputes or execution errors. BIM radically transforms this activity, moving from paper-based or email documentation management to a centralized and immutable data management.

Documenting a variant in a BIM environment means integrating the modification within the overall information flow, ensuring that every actor in the supply chain (from the designer to the contractor, and the client) is aligned on the latest approved version.

Traceability and Dynamic Comparison Between Versions

The main advantage lies in the ability to archive and compare different “versions” of the model thanks to the BIM management system or the common data environment. When the need for a variant arises, the designer does not delete the previous work, but creates a branch of the model or uses specific revision sets. This allows for documenting not only the final state but also the technical reason and the evolution that led to that specific choice.

• immediate data retrieval – each change to the parametric elements automatically updates cost and time parameters;
• visualization of interferences – before approving a change order, it is possible to perform a new Clash Detection to ensure the variant does not create conflicts with existing systems or structures;
• informed approval – the client can visualize the impact of the variant through rendering or virtual reality even before the service order is signed, drastically reducing post-installation reconsiderations.

Integration Between Model and Legal Documentation

Documenting a variant is not only graphic but primarily administrative. In a BIM workflow, the change order is directly linked to the model’s objects. For instance, if one decides to change the type of windows during the construction phase, the software simultaneously updates the window schedule, technical specifications, and cost estimate.

This synchronization ensures that the “As-Built” (the model as built) evolves in parallel with the work, eliminating the dangerous disconnect between what was authorized by the technical offices and what is actually realized on site. Documenting variants thus becomes a fluid and less burdensome process, as the production of new graphical documents and expense justifications is an automatic derivation from the updated model.

From 3D model to technical documents

Now let’s see how to practically proceed to obtain all the technical documents starting from a 3D model.

Creation of the Project Group document

In Edificius, to obtain the comparison graphic sheets we use the file “Project Group“.

On the “New” page of the “Home” in Edificius, we select the file type “Project Group” and from the dialog, we indicate the document that represents the “existing status“.

The “Project Group” generates a group file and a copy of the “document” of the “existing status” (SdF) which becomes the “document” of the “design status” (SdP) to work on.

Document management of the Project Group

In the “Project Management” window, a “Project Group” document is directly linked to the “Existing Status” (yellow color) and “Design Status” (red color) documents.

By selecting one of the three documents, you can access the respective “Navigators” for document management.

Specific functions within the program allow you to activate/deactivate the comparison between SdF and SdP or to compare the two views of the project in a single environment.

Project Group: the tools

Edificius provides specific tools such as: demolisher, trowel, and wand with which it is possible to intervene on the architectural objects in the “design status“.

When strictly necessary, it is also possible to intervene on the “Existing Status” document.

In this case, the demolisher, trowel, and wand tools take on different functions compared to those in the design status.

Normally, the document of the existing status should not be modified.

However, Edificius offers the possibility to intervene on the Existing Status document through the “unlock” function.

Creating comparison graphic sheets with the Project Group

With the Project Group document, it is possible to create “graphic sheets” (floor plans, layouts, sections, elevations, axonometries) and “documents” (reports, tables, and summaries, executive sheets) for managing all information compared between the “existing status” and the “design status“.

From the “design status“, we can automatically generate a comparison graphic sheet composed of three documents:

• Removed/Demolished (existing status)
• New/Built (design status)
• Comparison

The demolished entities of the SdF are highlighted in yellow, the built entities of the SdP in red, and both demolished and built entities are displayed simultaneously in the comparison sheets.

FAQ on Managing Renovation Works and Variants

Why is BIM essential in new construction and renovation projects?

The essence of BIM lies in its ability to manage complexity. In a building recovery project, it allows the existing structure to coexist with the new by integrating geometric, structural, energy, and temporal data. This enables the designer to anticipate conflicts that in the past would have only emerged during the execution phase, ensuring millimeter precision, reducing extra costs through clash detection, and providing transparency to the client.

How are interior design and renovation managed in a single 3D model?

Adopting a BIM-oriented approach allows for the convergence of the macroscopic vision of the building with the detail of the furnishings in a single design environment. Through temporal filters and comparison tools, the software overlays the ‘as-is’ state and the ‘project state’, allowing for the testing of distribution variants and instant verification of the impact on the structure and final aesthetics.

How does BIM facilitate the documentation of project variants?

BIM transforms the management of variants from paper-based documentation to centralized data management. Every change to parametric elements automatically updates costs, timelines, schedules, and metric calculations. This ensures that the “As-Built” model evolves in tandem with the work, eliminating the disconnect between what has been authorized and what has been executed on site.

What is the Project Group in Edificius and what is it used for?

In Edificius, the “Project Group” is the file used to obtain comparison graphic tables. It generates a group file that links the ‘As-Is State’ document (yellow color) and the “Project State” document (red color), allowing for dynamic comparison and the use of specific tools like the demolisher and trowel.

How are the comparison graphic tables (yellow and red) created?

From the “project state” level, it is possible to automatically generate a graphic table composed of three documents: Removed/Demolished (as-is state), New/Built (project state), and Comparison. Entities demolished are highlighted in yellow, constructed entities in red, and both entities are displayed simultaneously in the comparison tables for immediate reference.