BIM and Autodesk Ecotect (1-2-3 Revit Tutorial)1 Dec, 2008 By: AIA ,Rick Rundell
How BIM and Autodesk Ecotect help architects understand their conceptual building design's performance.
Editor's note: This tutorial courtesy of Autodesk.
For most building projects, decisions made in the first few weeks of the design end up having the greatest impact on a building's performance. The location of the building on the site, its basic form and orientation, its internal layout and external materials selection, its fenestration -- all of these factors are set very early on in the design process and often with no analysis data to support the decisions.
My previous article in this column looked at Autodesk Green Building Studio, a web-based energy analysis service that can help architects and designers perform whole building analysis, optimize energy efficiency, and work toward carbon neutrality earlier in the design process. This month's article explores another tool that architects can use to analyze their BIM-based designs and get early feedback on the performance of their building design: Autodesk Ecotect.
Working with the Environment
To mitigate a building's impact on the environment, it's important to first understand how the environment will impact the building. Built specifically by architects and focused on the building design process, Autodesk Ecotect is an environmental analysis tool that allows designers to simulate the performance of their building projects right from the earliest stages of conceptual design.
Acquired by Autodesk in June 2008, the software combines a wide array of analysis functions -- including shadows, shading, solar, lighting, thermal, ventilation, and acoustics -- with a highly visual and interactive display that presents analytical results directly within the context of the building model. This visual feedback enables the software to communicate complex concepts and extensive datasets, and helps designers engage with multifaceted performance issues -- at a time when the design is sufficiently 'plastic' and can be easily changed.
Analyzing a BIM-based Design
Revit-based design models can be exported to gbXML format and imported directly into Autodesk Ecotect for analysis throughout the design process. At the onset of the design process, early-stage, Revit-based massing models can be used in combination with the site analysis functionality to determine the optimal location, shape, and orientation of a building design based on fundamental environmental factors such as daylight, overshadowing, solar access, and visual impact.
As the conceptual design evolves, whole building energy solutions, such as Green Building Studio, can be used to benchmark its energy use and recommend areas of potential savings. Once these fundamental design parameters have been established, the software can be used again to rearrange rooms and zones, to size and shape individual apertures, to design custom shading devices or to choose specific materials based on environmental factors such as daylight availability, glare protection, outside views, and acoustic comfort.
Early-stage, Revit-based massing models can be used in combination with the site analysis functionality to determine the optimal location, shape, and orientation of a building design based on fundamental environmental factors such as the overshadowing of a particular building (highlighted in red) shown here.
Autodesk Ecotect can also be used for detailed design analysis. For example, the visibility analysis displayed here shows the amount and quality of views to the outside mapped over the floor area of an office.
But perhaps the most unique aspect of the software is its visual and interactive display of the analysis results. The inability of the designer to easily interpret the results of analyses is often the biggest failing of building performance analysis software. Autodesk Ecotect provides actionable feedback to the designer in the form of text-based reports as well as visual displays. These visual displays are more than just charts and graphs. The analysis results are presented directly within the context of the model display: shadow animations resulting from shadow casting analysis, surface mapped information such as incident solar radiation, and spatial volumetric renderings such as daylight or thermal comfort distribution in a room.
This type of visual feedback lets designers more easily understand and interact with analysis data, often in real time. For instance, a designer can rotate a view of surface-mapped solar radiation looking for variations over each facade, or watch an animated sequence of solar rays to see how sunlight interacts with a specially designed light-shelf at different times of the year.
Architects can see the results of their analysis displayed in the context of a building model, such as the surface mapped results of this solar radiation analysis.
Autodesk Ecotect software also displays analysis results using spatial volumetric renderings, such as this analysis of the visual impact of a building within an urban site.
Building Performance Analysis
During conceptual design, Autodesk Ecotect and the Revit design model can be used for a variety of early analysis. For example, the designer can perform overshadowing, solar access, and wind-flow analyses to iterate on a form and orientation that maximizes building performance without impinging on the rights-to-light of neighboring structures.
As the design progresses and the elements that define a building's thermal zones are established (the layout of the walls, windows, roofs, floors, and interior partitions), the Revit model can be used for room-based calculations such as average daylight factors, reverberation times, and portions of the floor area with direct views outside.
Eventually the Revit model can be used for more detailed analysis, such as shading, lighting, and acoustic analysis. For example, the designer can use Autodesk Ecotect in conjunction with a shading louver design modeled in the Revit model to simulate how the design will work under different conditions throughout the year. Or the architect can use the software to assess the acoustic comfort of a Revit-based design and then adjust the location of a sound source or adjust the internal wall layout and/or the geometry of sound reflectors for optimal comfort.
The consistent, computable data that comes from a Revit-based BIM workflow, combined with the breadth of performance analysis and meaningful feedback of Autodesk Ecotect, enables a holistic approach that architects can use to simulate and analyze their designs. This feedback -- particularly during early conceptual design -- is critical for architects to optimize the performance of their building designs.