Building Information Modeling (BIM) is crucial for efficient project execution and coordination across various disciplines such as architecture, structural engineering, mechanical, electrical, and plumbing (MEP). Within the BIM ecosystem, Autodesk Revit is a popular tool that allows users to manage multiple models through different import techniques. When working with multiple models, ensuring alignment and accuracy between them is vital. This is where Revit’s model import settings come into play. Understanding how to effectively use these methods can prevent significant misalignment issues and improve the collaboration process.
In this article, we’ll explore several Revit model import techniques, each designed for specific coordination scenarios: Auto - Origin to Origin, Auto - Center to Center, Auto - By Shared Coordinates, Auto - Project Base Point to Project Base Point, and manual methods.
1. Host vs. Linked Models in Revit
Before diving into the import methods, it's essential to distinguish between Host Models and Linked Models in Revit.
Host Model: This is the main project file in which you’re working. The host model serves as the central file where other models are brought in for coordination.
Linked Model: This refers to external models, often from other disciplines (like architecture, structural, or MEP), which are linked into the host model for coordination.
2. Auto - Origin to Origin
In Origin to Origin placement, both the host and the linked models are aligned using their predefined origins. Typically, this is effective when both teams (such as architectural and structural) have started their models from the same origin point. For example, if both models have the southwest corner of the site as the origin, Revit will align them without any manual adjustments. This method is quick and straightforward, provided the models are based on the same common origin point.
Best use case: When working with models that share a predefined origin point, such as in a large-scale project where multiple teams have already agreed on the common reference.
3. Auto - Center to Center
The Center to Center method aligns the geometric centers of the host and linked models. This approach is useful when precision at the origin point is not critical, and overall centering is sufficient. For instance, when bringing in a large equipment model into a building (such as a mechanical model of a large pump), the bounding box's center is
aligned, ensuring the overall centering without being tied to a specific origin point.
Best use case: When importing models where general centering matters more than precise origin alignment, such as large mechanical components.
4. Auto - By Shared Coordinates
For large projects involving multiple disciplines like architectural, structural, and MEP, the Shared Coordinates method is the most precise. In this approach, models are aligned using predefined shared coordinates that each team has agreed upon. For example, when the MEP model is imported using shared coordinates, it aligns exactly with the architectural model, ensuring that all systems (like HVAC, plumbing, and electrical) fit together seamlessly within the building.
Best use case: Complex projects involving multiple teams that require high levels of accuracy in coordination between architectural, structural, and MEP models.
5. Auto - Project Base Point to Project Base Point
This method uses the Project Base Point from both the host and linked models for alignment. It's most applicable when working on projects that span multiple buildings or have different parts of the same building. Each building might have a unique base point, such as the entrance or the main corner of the building, and using this method ensures that all parts sit correctly on the site plan.
Best use case: Projects with multiple buildings or sections where each part has a unique project base point that needs alignment.
6. Manual - Origin
In some cases, the automated alignment methods may not suffice. For instance, when importing landscape models that were created with their origin at a free location (i.e., not tied to a predefined site point), manual alignment becomes necessary. In these cases, the user can manually position elements by aligning the origin to a specific point within the host project.
Best use case: When importing models that do not adhere to a predefined origin, such as landscape design models.
7. Manual - Base Point
Similar to manual origin positioning, the Base Point manual adjustment method is useful when importing neighboring site models. For example, if a site model’s base point is set at the front gate of the building, the user manually adjusts the model to ensure that the gate aligns properly with the entrance of the building in the host model.
Best use case: When models need to be aligned using specific site points, like the front gate of a building.
8. Manual - Center
In this scenario, large models like sculptures or other park elements are manually centered. The bounding box of the sculpture has its center at the middle, which can be manually adjusted to fit within the project’s layout, such as a central plaza or garden.
Best use case: When importing objects like sculptures that require precise manual centering in specific project locations, such as parks or plazas.
Efficient model coordination is crucial for BIM workflows, especially in multidisciplinary projects. Revit provides several automated and manual model import options that cater to different scenarios, ensuring that models align correctly without extensive manual adjustments. Understanding and selecting the appropriate import method—whether it’s based on origin, center, shared coordinates, or base points—can save time, reduce errors, and improve project collaboration. By mastering these methods, teams can ensure seamless coordination between architectural, structural, and MEP models, leading to a more efficient project delivery.
Are you struggling with model coordination in your BIM projects? Try out these Revit import techniques to streamline your workflow and ensure better collaboration across teams. Experiment with the different methods in your next project, and see how proper model alignment can enhance project efficiency.