In this lesson, students experience the process of identifying areas of a project where multiple design options are being considered and a workflow for exploring, evaluating, and presenting those options within a single integrated design model.
The suggested exercises present two examples of varying scales; they:
- Consider options for the design of an entire building wing.
- Compare alternatives for room layouts in a portion of a building.
Defining Option Sets and Options Within Each Set
Designers often explore many options and possible alternatives to particular design problems in their quest for the best design solutions. For example, designers might consider several options to:
- Fit out and furnishing an interior space
- Provide a landmark canopy over the entrance to a building
- Articulate the balcony railings on a prominent building façade
A BIM-based design process enables designers to define key features or areas where sets of design options will be considered and manage the proposed options in the context of the overall design. Designers can define as many options sets as needed to evaluate proposed design alternatives—there is no limit.
Rather than maintaining separate models for each of the proposed options, a single model is used to coordinate the design of all options. The main building model includes all the elements that are fixed—that is, not affected by the options being explored—and thus, acts as a backdrop in which the design options can be evaluated. This single model approach ensures consistency as the design progresses and continues to evolve.
Presenting and Comparing Design Options
Separate views are typically created that display each design option in the context of the main model for presentation to the design team, clients, and other stakeholders in the review process. These views can be presented individually or placed on a single sheet for easy comparison.
One of the options in each design option set is assigned to be the primary option or leading candidate among the options being considered. By default, the features of this option are displayed in model views. To easily see and consider additional design options, views can be duplicated and each view can be set to display a specific design option.
This ability to display the elements in specific design options extends to all model views including schedules. This powerful feature enables design options to be fully evaluated in both graphical and tabular views. For example, one wall schedule can tabulate data for the primary option and another wall schedule can present the revised data for a secondary option.
After the design options have been considered and the preferred option has been selected, that option can be accepted as the primary design solution and moved back into the main model. When a design option is accepted, elements in the other design options are removed from the building model to reduce the file size and improve model efficiency. This approach is recommended if you have made a definite design decision and intend to move forward with that decision. Keeping unused and out-of-date options in the project needlessly inflates the file size and adds unwanted complexity.