Lesson 1: Modeling for Construction

Key Concepts

In this lesson, students explore how to create building models that more accurately reflect the construction techniques that will be used for the materials and systems specified. As the use of the BIM models that they create expands beyond design activities, the need to deliver accurate models and improve communication of design intent becomes critical to the success of the entire project team.

Students will explore how to model building elements and structural systems to reflect common construction practices. They will use a new tool available in the Autodesk Revit platform—parts—to break multi-layer elements into pieces to improve BIM models for construction planning and estimating use. They will also learn to create 3D details and exploded views to enhance their design communications.

The Evolving Roles of Designers and BIM Modelers

As the applications of BIM models continue to evolve and extend beyond design phase activities to supporting information needs throughout the project lifecycle, the importance of accurately modeling the elements of a building or facility grows and becomes critical to the success of all project participants and model users.

The role of designers and BIM modelers is rapidly expanding. As creators of much of the information in a BIM model, they are expected to accurately modeling the elements of a building in a way that serves their needs, as well as downstream and sometimes unforeseen uses of the model.

Some argue that this evolving role is analogous to master builders, who once guided and were ultimately responsible for all aspects of building projects. But that analogy is not appropriate—given the size of complexity of modern construction projects, no individual can carry that load. A better analogy might be to compare designers in a BIM process to orchestra conductors, who understand and appreciate the unique qualities and needs of each of the players, and focus on keeping them all working harmoniously to create exquisite results.

No individual player or BIM modeler can effectively wear all the hats and embody the skills and expertise present in the full project team. So, finding ways to incorporate the unique strengths and value added by each expert, as well coordinating and synthesizing their efforts into a cohesive workflow is the approach we must take.

For this approach to be successful, it is paramount that the BIM model, which serves as the vehicle for storing, synthesizing, and communication information about the building project, accurately convey design intent.

Guiding Themes

Model at an appropriate level of detail, relative to the stage or phase of the design process.

At the early conceptual design stage, focus on the big gestures (placement, massing, and orientation) and don’t get lost in the fine details. As the design matures through design development and construction documents, successively add more detail as information about building elements is decided.

Understand your design goals, and use a targeted, iterative design process.

Don’t get distracted by the seemingly infinite design options available in modern modeling software. Explicitly understand the project team’s design goals and priorities, and use these to guide your design exploration. Use an iterative process—model, design, evaluate, and then refine. Use the constructability, cost, and building performance feedback available through analysis of the model to inform design decisions.

Model it as it will be built, and accurately convey design intent.

Sloppy shortcuts to make model views look right and hide modeling inaccuracies should be avoided when possible. The building elements and the relationships between them encoded in the building model must be buildable and useable for all downstream users and model clients. And these users are depending on the accuracy of the model.

Additional Resources

Online

Publications

Haymaker, J., & Fischer, M. (2001) Challenges and Benefits of 4D Modeling on the Walt Disney Concert Hall Project. CIFE Working Paper #64, Stanford University
Heesom, D., and Mahdjoubi, L. (2004) Trends of 4D CAD Applications for Construction Planning Construction Management and Economics, n.22, p. 171-182.
Dawood, N., and Mallasi, Z. (2006). Construction Workplace Planning: Assignment and Analysis Utilizing 4D Visualization Technologies Computer-aided Civil and Infrastructure Engineering, p. 498-513.
Hartmann, T., Gao, J., and Fischer, M. (October 2008) Areas of Application for 3D and 4D Models. Journal of Construction Engineering and Management, n.135, issue 10, p.776-785.

WikiHelp

Detail Level

Setting Detail Level Scale Values

Specifying the Detail Level for a View

Managing Family Visibility and Detail Level

Structural Columns

Placing a Vertical Structural Column

Placing Slanted Structural Columns

Placing Multiple Columns by Grid

Adjusting Slanted Column Geometry End Position and Trim

Modifying Structural Columns

Adding a Splice Symbol or Plate Symbol to a Steel Structural Column

Parts

Creating Parts

Dividing Parts

Deleting Parts

Controlling Part Visibility and Appearance

Editing Part Divisions

Part Instance Properties

Editing Part Geometry

Assemblies

Creating Assemblies

Editing Assemblies

Disassembling Assemblies

Deleting Assemblies

Assembly Type Properties

Creating Assembly Views and Sheets

Assembly Instance Properties

Tags and Keynotes

Adding Tags and Keynotes in a 3D View

3D Views

Creating 3D Details

Objectives

After completing this lesson, students will be able to:

Appreciate the importance of modeling building elements in a manner that matches the planned construction materials and methods.
Understand and use specific model techniques available in the Autodesk Revit platform to accurately model the spans, boundaries, and layers of building elements for construction.
Use 3D views, tags, and keynotes to improve communication of design intent and ensure consistency.

Key Terms

Key Term	Definition
Level of Detail	Level of detail refers to the degree of precision of the elements included in a BIM model.Early in the design process, the model has a comparatively low level of detail. As the design process continues and specific details of the building elements are added to the model, the level of detail increases. For an efficient work process, it is important to be aware of the appropriate or needed level of detail and model the building elements accordingly.
Parts	Part elements in Revit support the construction modeling process by letting you divide certain elements from the design intent model into discrete parts. These parts, and any smaller parts derived from them, can be independently scheduled, tagged, filtered, and exported. Parts can be used by construction modelers to plan delivery and installation of pieces of more complex Revit elements.
Exploded view	An illustration depicting the disassembled individual components in proper relationship to their assembled positions. Exploded views are often used to illustrate the details of multi-layered or multi-part assemblies.
Tags	Tags are annotations for identifying and displaying information about and properties of the elements in a model. The properties of an element associated with a tag can be displayed in schedules.
Keynotes	Keynotes enable you to tag model elements (including detail components) and materials with text from a separate text file. Keynotes assigned in a project are linked to their source keynote table. When the keynote table is changed, keynotes in the project will reflect the changes when the project is closed and reopened.

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