A national laboratory of the U.S. Department of Energy

Office of Energy Efficiency & Renewable Energy

National Renewable Energy Laboratory 

Innovation for Our Energy Future 

Energy Design Plugin: An 

EnergyPlus Plugin for SketchUp 

Preprint 

P.G. Ellis and P.A. Torcellini 

National Renewable Energy Laboratory 

D.B. Crawley 

U.S. Department of Energy

Presented at IBPSA-USA SimBuild 2008 Conference 

Berkeley, California 

30 July – 1 August, 2008 

Conference Paper 

NREL/CP-550-43569 

August 2008 

NREL is operated by Midwest Research Institute ● Battelle Contract No. DE-AC36-99-GO10337 
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ENERGY DESIGN PLUGIN: AN ENERGYPLUS PLUGIN FOR SKETCHUP*

Peter G. Ellis1

, Paul A. Torcellini1, and Drury B. Crawley2

1

National Renewable Energy Laboratory, Golden, CO 

2

United States Department of Energy, Washington, DC 

 

* This manuscript has been authored by Midwest Research Institute under Contract No. DE-AC36-99GO10337 with the U.S. Department of 

Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States 

Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or 

allow others to do so, for United States Government purposes.

ABSTRACT

This paper describes the Energy Design Plugin, a new 

software plugin that aims to integrate simulation as a 

tool during the earliest phases of the design process. 

The plugin couples the EnergyPlus whole-building 

simulation engine to the Google SketchUpTM drawing 

program. Leveraging the powerful SketchUp 

application programming interface, we developed a 

plugin that extends the capabilities of SketchUp to 

allow EnergyPlus building models to be developed in 

3-D while taking advantage of all of the native 

SketchUp capabilities, including intuitive tools, 

different rendering modes, and realistic shading. The 

model geometry can be saved to create an EnergyPlus 

input file. Existing input files can be opened, edited in 

the SketchUp environment, and saved again. Already 

well-established as a popular tool among architects and 

designers, SketchUp offers a familiar, easy-to-use 

interface that, when coupled with the plugin, could 

make building energy simulation more accessible for 

architects, designers, and students during the design 

process. 

KEYWORDS

energy simulation, EnergyPlus, SketchUp, graphical 

user interface, design process, conceptual phase 

INTRODUCTION

Although building energy simulation is a useful tool for 

predicting performance and comparing design options, 

most energy simulation occurs too late in the design 

process. In the traditional design process, the energy 

engineer uses simulation (if at all) as a tool for 

equipment sizing and code compliance only after the 

architect has completed the architectural design. Part 

of the problem is that existing simulation tools are not 

practical for the design process. Ideally, the design 

team would use building energy simulations to guide 

the architectural design from the earliest phases of the 

project. Experience with real buildings has shown that 

low-energy design is not intuitive and that simulation 

should therefore be an integral part of the design 

process (Torcellini et al. 1999; Hayter et al. 2001). But 

this is usually not possible because the development of 

the energy model that describes the building design is 

time-consuming and requires a skilled specialist. 

EnergyPlus is a whole-building energy simulation 

program developed by the U.S. Department of Energy 

(DOE). EnergyPlus is the next generation of building 

simulation program and offers many advanced 

simulation capabilities (Crawley et al. 2004). 

However, EnergyPlus is a simulation engine only—it 

does not have its own graphical user interface (GUI). 

Manually entering detailed, 3-D geometry data can be 

difficult and prone to errors. Third-party GUIs for 

EnergyPlus are approaching maturity, but are not 

necessarily aimed at the earliest phases of the design 

process. 

In 2005, we began a task to find ways to integrate 

simulation into the earliest phases of the design 

process. Work on the Energy Design Plugin began as a 

pilot project to explore the coupling of EnergyPlus to a 

commercially-available 3-D drawing package. The 

concept was to leverage the capabilities of an 

established GUI and build on an existing market and 

user base, instead of developing an entirely new 

program from scratch. 

We began further development of the plugin in 2007 

with the objective to deploy a version of the Energy 

Design Plugin for public use. It was decided that the 

plugin and its source code would be released under an 

open source license to encourage collaborative 

development on future versions. 

1 
SKETCHUP

Google SketchUpTM 6 is a 3-D drawing program that 

offers the advanced visualization capabilities of more 

expensive computer-aided design (CAD) packages, but 

with a much simpler and more intuitive interface that 

facilitates the rapid sketching of designs. SketchUp is 

available in free and professional versions for 

Microsoft Windows or Mac OS X platforms. (The 

plugin will work with either free or professional 

versions, but currently only on Windows. A Mac OS X 

plugin is under development for a future release.) 

The hallmark of SketchUp is its easy-to-use GUI. The 

program enables a user to easily manipulate and edit 

designs in 3-D. As with a CAD program, the user can 

still accurately measure distances and add dimension 

markings. The program also features a variety of 

rendering options, including bitmap textures, 

shadowing, and x-ray mode, as well as traditional 

rendering modes such as black-and-white line 

drawings, or a rough “sketchy” style that imitates a 

hand-drawn architectural draft. By entering the 

longitude, latitude, date, and time, SketchUp can 

perform shadowing studies for a project. The 

shadowing feature can be useful for examining passive 

solar building designs. 

Part of the appeal of coupling EnergyPlus to SketchUp 

is that it is already a well-known and popular tool 

among architects, designers, and students. Firsthand 

accounts suggest that SketchUp is widely used by 

architects during the conceptual phases of projects. An 

initial design proposal is rapidly “sketched” with 

SketchUp to show the building form and massing, and 

then submitted to the client. The client provides 

feedback to the architect and requests changes. The 

architect and client might iterate over several SketchUp 

models until the client is fully satisfied with the design 

concept. The project then moves forward to design 

development, where the SketchUp model is exported to 

become a much more detailed CAD model. The 

conceptual phase of the design process—when the 

SketchUp models are being used by architect and client 

to make decisions about the building form and 

massing—is precisely when energy simulation can 

provide the most helpful feedback to influence the 

design. SketchUp is optimally positioned in the design 

process workflow for coupling to an energy simulation 

tool. Once the project moves to the CAD model, it is 

usually too late or too expensive to revisit the design of 

the building form and massing. 

Application Programming Interface 

The strength and flexibility of the SketchUp application 

programming interface (API) is another reason that the 

program was selected for the original pilot project. 

The SketchUp API allows plugins to be created that 

add custom functionality to the program. 

The API provides access to most of the functionality of 

the SketchUp user interface. It enables custom controls 

such as menus, toolbars, and specialized drawing tools 

to be added. The API can interact directly with the 

SketchUp model to inspect, create, modify, and delete 

3-D objects. The underlying paradigm for the API is 

fully object oriented. 

All the API calls are accessed by using the Ruby 

programming language (Matsumoto 2001; Thomas 

2005). Ruby is a high-level, object-oriented language 

similar to Smalltalk or Lisp, and is an interpreted 

language like Perl or Python. Because Ruby programs 

are not compiled, they are often easier and faster to 

develop. They do, however, require a separate 

interpreter program to run them. SketchUp provides its 

own embedded Ruby interpreter to execute all the code 

for plugins. Another advantage of Ruby, like many 

interpreted languages, is that it is platform-independent 

and can run the same code on Windows, Mac OS X, or 

Linux. Although Ruby has no native GUI capabilities 

for handling dialog windows or graphics, it can be 

coupled to several third-party GUI toolkits. 

ENERGY DESIGN PLUGIN

An alpha version of the Energy Design Plugin was 

released in January 2008 to a small group of testers. 

The first beta version (0.9.3) was publicly released in 

early April 2008. 

Features 

The current release of the plugin (0.9.4) has three 

major features: 

• Geometry editing capabilities 

• EnergyPlus run manager 

• Data visualization capabilities 

First and foremost, the plugin is an easy-to-use 

geometry editor for EnergyPlus. It allows the user to 

create a building geometry from scratch: add zones, 

draw heat transfer surfaces, draw windows and doors, 

draw shading surfaces, etc. All EnergyPlus geometry 

objects are drawn with the standard tools provided by 

SketchUp. The SketchUp model can then be saved as 

an EnergyPlus input file. Existing input files can also 

be opened with the plugin, edited in the SketchUp 

environment, and saved again (Figures 1 and 2). 

If the input file is complete, the plugin can use the run 

manager to launch an EnergyPlus simulation. When 

2 
the simulation is finished, the Annual Building Utility 

Performance Summary (ABUPS) generated by 

EnergyPlus can be automatically displayed in 

SketchUp. Other reports, such as the error file or 

report variable data, can be opened automatically in a 

text editor or in an Excel spreadsheet, respectively. 

Finally, the plugin includes capabilities for data 

visualization. After a simulation is run, the raw data 

output file (.ESO) generated by EnergyPlus can be read 

and parsed by the plugin. A rendering manager allows 

the user to choose report variables that should be 

associated by surface or by zone. The rendering 

manager then paints the SketchUp surfaces with a 

false-color scale according to the value of the report 

variable at a given date and time. A color scale or a 

gray scale can be selected. The user selects the date 

and time using the SketchUp shadow settings for a 

snapshot visualization of the data. One application 

could be to render the surface colors by outside surface 

temperature, or to render the zones by mean air 

temperature. An animation manager takes data 

visualization to the next level by automatically stepping 

time forward or backward at user-defined intervals to 

create a dynamic, animated rendering of the data. 

Now that we have described what the plugin can do, it 

is perhaps equally important to clarify what it cannot 

do. The plugin is not a full-featured interface for 

EnergyPlus. It does not provide a way to create or edit 

nongeometry EnergyPlus objects such as materials, 

constructions, schedules, internal heat gains, and 

HVAC equipment and systems. Currently, to 

effectively use EnergyPlus with the plugin, the user 

must have expertise in building simulation and be 

willing to work with the EnergyPlus syntax of the text 

input file. Alternatively, the user could work with the 

plugin in conjunction with another third-party interface 

to make the job easier. 

The plugin is also not a translator from SketchUp to 

EnergyPlus. It cannot automatically convert a 

SketchUp model into an EnergyPlus input file. To use 

the plugin as intended, the user must have the energy 

model in mind from the beginning as the SketchUp 

model is being created. 

Audience 

The initial target audience for the first release of the 

plugin is firmly based on EnergyPlus users who wish to 

rapidly generate building geometry input—often the 

most time-consuming part of creating an EnergyPlus 

input file. Prospective EnergyPlus users who were 

previously put off by the difficulty of manually entering 

the geometry input will now find it more accessible 

with the plugin. 

Because SketchUp is a popular tool for architects and 

designers, we have already seen growing demand 

among professionals who ordinarily would not use 

simulation but are eager to acquire the appropriate 

tools. At this stage, the plugin is not ready to go that 

far mainstream. 

If the mission of the Energy Design Plugin is “to 

integrate energy simulation into the earliest phases of 

the design process,” perhaps implicit in this statement 

is the requirement that the plugin be easy-to-use for 

those who are not experts in simulation. After all, 

simulation experts have not been traditionally involved 

during the conceptual phase. We might argue that 

simulation experts should be involved from the earliest 

phases of the project, but the reality is that most 

projects will not enjoy that luxury. Usually the 

conceptual phase is the domain of the architect. For 

future releases, the ultimate goal must be to develop the 

plugin into a software tool that these professionals 

would be comfortable using to produce reliable energy 

simulation results. 

Guiding Principles 

The overall development of the Energy Design Plugin 

has been influenced by the following guiding 

principles: 

1. Focus on the conceptual phase 

The conceptual phase is a critical time for introducing 

energy simulation into the design process. In this 

phase, changes can be made to the building form and 

massing that can significantly reduce building energy 

use, yet add little to the cost. By the time the project 

moves to the later phases of the design process, it is 

usually too late to make major changes to form and 

massing. 

As one possible option for the conceptual phase, our 

research in 2005 evaluated integration of energy 

simulation with CAD tools using Industry Foundation 

Classes (IFC). Significant research and development 

has been put into advancing IFC as a means for 

exchanging building geometry data between CAD 

programs and energy simulation programs (Bazjanac 

and Crawley 1997; Karola et al. 2001; O’Sullivan and 

Keane 2005). Much of this research has specifically 

targeted EnergyPlus as the energy simulation program. 

The fundamental drawback to CAD programs in 

general is that they are simply not designed for creative 

design exploration and rapid concept development. 

This explains why they are seldom used for the 

conceptual phase. In the end, we decided to develop 

the plugin around SketchUp because it is the design 

3 
tool of choice for architects during the conceptual 

phase. 

2. Develop architectural and energy models together 

One challenge of the CAD-to-IFC-to-EnergyPlus path 

is that it is difficult for software to automatically derive 

an energy model from a full-blown architectural CAD 

model. In most cases the architectural model contains 

many details that are irrelevant for energy simulation. 

The process of trying to identify and simplify the 

important geometry is complex. Instead of attempting 

to tackle this problem anew, we opted for an entirely 

different approach. 

The approach we chose for the plugin requires the user 

to develop the architectural model and the energy 

model simultaneously. The user defines both models 

explicitly in the same SketchUp environment at the 

same time. Where appropriate, the two models can 

share the same geometry. For instance, the user can 

define a wall as an element of the energy model, yet 

can also decorate the wall with architectural elements 

like crown molding, baseboard, and lighting fixtures. 

Explicitly defining the energy model avoids the 

difficulties and errors inherent in attempting to 

automatically infer one model from the other. Instead, 

the user develops the energy model exactly as required. 

This approach also offers the added reward of engaging 

users to begin to think about energy as they create the 

building design. 

The capability to combine the architectural and energy 

models means that EnergyPlus geometry objects can 

coexist with purely decorative content such as 

architectural details, landscaping, Google Earth images, 

people, furniture, and vehicles—all in the same 

SketchUp environment. 

The current release of the plugin does not implement 

all the functionality to make this approach a reality, but 

this capability will be a core feature of version 1.0. 

3. Integrate seamlessly with SketchUp 

Much of the popularity of SketchUp can be attributed 

to the design of its GUI. The GUI is the main reason 

the program is easy to use and can facilitate rapid 3-D 

drawing. 

Where possible, the plugin GUI imitates the SketchUp 

GUI and strives to integrate seamlessly with it. A 

familiar GUI helps SketchUp users feel comfortable 

working with the plugin by providing the same look 

and feel between SketchUp and the plugin. 

The plugin integrates the standard SketchUp tools for 

drawing and manipulating the view. The plugin 

automatically recognizes different surface types as they 

are being drawn. Walls, roofs, and floors are identified 

by the orientation of their outward normal vectors. 

Windows and doors are inferred based on their 

relationship to a base surface. 

The plugin is also linked to the SketchUp location 

settings and unit system settings. When a user changes 

one of these settings, the plugin is instantly updated 

with the new values. 

4. Allow two-way editing of EnergyPlus input files 

The plugin adopts the paradigm of an “editor” for 

EnergyPlus input files. As an editor, the plugin can be 

used to write and read input files. Most simulation 

software has a one-way interface: it can only write the 

input file. Our experience suggests that EnergyPlus 

users will always want to be able to use other tools 

such as a text editor to edit their input files. The twoway editing feature of the plugin preserves all the 

formatting and comments of the input file and changes 

only the geometry data that were modified through the 

GUI. 

5. Find cross-platform solutions 

SketchUp is available on Windows and Mac OS X 

platforms. Anecdotal evidence suggests that designoriented professionals such as architects often prefer 

the Mac OS X platform over Windows. With 

architects as a key audience for the plugin in future 

releases, it makes sense to develop a cross-platform 

solution for the plugin that supports both Windows and 

Mac OS X. 

The current release of the plugin is only available on 

Windows due to issues with the dialog feature of the 

SketchUp API for OS X. With more development, a 

cross-platform solution should be achievable. The 

Ruby plugin code is already inherently cross-platform. 

An OS X build of EnergyPlus has been made available 

since version 2.0. 

6. Release as open source 

Since the inception of the plugin, we have planned to 

release it under an open source license. A volunteerbased open source effort may be a viable way for 

sharing development costs across many collaborators, 

leveraging scarce federal funding. Open source 

projects also have a long-standing reputation for 

producing high-quality software (Fogel 2006). 

The current version is released under the GNU General 

Public License (GPL) (FSF 2007). The license allows 

anyone to freely copy and redistribute the plugin and its 

source code and to modify the source code, provided 

that if it is distributed publicly, the modified plugin 

must also be released under the GPL. 

4 
By embracing open source, we aim to provide a 

collaborative foundation for building a volunteer 

community of developers who are interested in 

improving the plugin. To that end, we wrote all the 

code with open source in mind. We paid close 

attention to the internal plugin architecture, and to 

useful programming conventions such as detailed 

comments, consistent naming standards, and consistent 

formatting. The result is a body of source code that we 

hope can be readily understood and extended by other 

developers. The next step will be to set up a project 

site for the plugin on a publicly-accessible open source 

web host such as SourceForge.net. 

Implementation 

The Energy Design Plugin is entirely implemented by 

interfacing with the SketchUp API. The bulk of the 

source code is a written in Ruby, but the plugin also 

contains some code in HTML and JavaScript. 

Development was facilitated by the API documentation 

(Google 2008). Note that due to limitations in the API, 

workarounds were needed in some cases. 

A primary job of the plugin is to track the SketchUp 

geometry as it is drawn by the user. But it is not 

necessary to track everything the user draws, because 

the SketchUp model can contain both EnergyPlus 

geometry and purely decorative geometry. To 

delineate which geometry is important for EnergyPlus, 

the plugin relies on the SketchUp concept of a Group. 

Groups can be created through the normal SketchUp 

interface as a way to associate or “group” multiple 

geometric objects together into a single entity. Groups 

provide a degree of isolation from the rest of the 

SketchUp model, but can still be opened for editing at 

any time. In the plugin, when the user creates a new 

EnergyPlus zone, they are actually creating an empty 

Group in SketchUp. From this moment forward the 

plugin knows that it must track changes inside that zone 

Group. Similarly, shading surfaces that are not 

associated with a zone (e.g., detached shading surfaces) 

are also organized into shading Groups. 

The mechanism for tracking the changes in a Group is 

the Observer class provided by the API. When the 

plugin creates a zone Group or shading Group, it 

creates and attaches an Observer object that tracks all 

the events inside that Group. When the user draws or 

erases a surface, the Observer notifies the plugin, which 

can update the EnergyPlus input file by adding or 

deleting the object. Each surface also has an individual 

Observer object assigned to it. When the user moves 

or resizes a surface, the surface Observer notifies the 

plugin and can update the EnergyPlus surface object 

with the new vertex coordinates. Observers are the 

heart of the plugin; they ensure that the EnergyPlus 

input file is always up to date. 

Dialog windows are another important part of the 

plugin GUI. Dialogs allow the user to edit EnergyPlus 

surface and zone properties, select simulation run 

settings, and manipulate various other inputs. The 

current release of the plugin uses the WebDialog class 

provided by the SketchUp API to create all of its 

custom dialogs. A WebDialog is a web browser 

embedded in SketchUp that can be filled with a 

Dynamic HTML (DHTML) document. DHTML is a 

ubiqitous web technology that adds dynamic behavior 

to an HTML web page using the JavaScript language 

and Cascading Style Sheets. The plugin uses DHTML 

to create dialogs that contain typical GUI widgets like 

buttons, radio buttons, check boxes, and text boxes. 

The result is a plugin dialog that looks very much like a 

standard Windows dialog. 

Future Development: Version 1.0 

As we continue to develop the plugin toward version 

1.0, we will add more core capabilities and improve its 

current capabilities. Descriptions of some of the major 

new features planned for version 1.0 follow: 

1. Persistent association between SKP and IDF 

The current release of the plugin manages the 

EnergyPlus input file (.IDF) separately from the 

SketchUp file (.SKP). A new feature will implement a 

persistent association between SKP and IDF. When 

the user opens the SKP file, the IDF file will be opened 

automatically. When the user saves the SKP file, the 

IDF file will also be saved automatically. A persistent 

association will allow the user to include decorative 

SketchUp elements along with the EnergyPlus objects. 

This feature is an important step for realizing the full 

potential for developing the architectural and energy 

models together in the same SketchUp environment. 

2. Automatic interzone connections 

The process of assigning interzone connections 

between heat transfer surfaces is a boring chore under 

the current release. The user must manually set the 

boundary conditions on each surface separately. A new 

feature for automatically detecting interzone 

connections will allow the user to move one zone to 

touch another zone and have the plugin automatically 

set the boundary conditions on the adjoining walls, and 

subdivide the surfaces as necessary. 

3. Advanced dialog GUI 

Version 1.0 of the plugin will shift away from using 

DHTML to create the plugin dialogs. An open source 

GUI toolkit called wxRuby (2008) has been selected to 

5 
replace the current DHTML dialogs. WxRuby is a 

wrapper for the cross-platform wxWidgets C++ library. 

WxWidgets provides a superior GUI look and feel 

because it uses the native widgets on each platform. 

Advanced dialog capabilities will make it easier to 

develop some of the GUI-intensive features below. 

4. Construction manager 

The current release requires the user to use a text editor 

or other interface to prepare constructions and 

materials beforehand. A new construction manager 

feature will allow the user to add, edit, and delete 

constructions and materials from an EnergyPlus input 

file, and manage libraries of constructions. The user 

will be able to assign a bitmap texture to each 

EnergyPlus material and render the energy model in 

texture mode. A “paint can” tool will allow the user to 

apply constructions to surfaces with a single click. 

5. Graphical display of simulation results 

In the current release, the standard EnergyPlus ABUPS 

report is used to present the simulation results. A new 

feature will postprocess the results and show a 

graphical display of the annual energy use. The results 

will be presented as a color bar chart with energy 

delineated by end use. Other graphical presentations 

may also be possible. 

6. Wizard for automatic model generation 

The current release is mainly a geometry editor. A new 

feature will expand the plugin beyond geometry to 

provide an interactive wizard that can automatically 

generate a prototype or “starter” model from scratch. 

The wizard dialogs will collect a set of high-level 

inputs from the user, including site location, building 

energy code, total floor area, number of floors, general 

building shape, building use, and HVAC system type. 

These data will be uploaded to a web service that 

shares the same preprocessor backend as the 

EnergyPlus Example File Generator (EEFG 2008). 

The preprocessor is a component of a larger 

multivariate optimization tool (Ellis et al. 2006). The 

preprocessor will automatically generate a fullyfunctional EnergyPlus input file from the metadata. 

The input file will then download to the user’s 

computer and can be opened in SketchUp for further 

editing. 

Future enhancements to the web service will also allow 

the plugin to upload an existing input file, 

automatically generate a code-compliant reference 

model, and download the revised input file back to 

SketchUp again. 

Future Development: Beyond 1.0 

Because the plugin is an open source project, the 

volunteer developer community will likely play a 

significant role in determining the direction of 

development beyond version 1.0. We imagine that 

developers will want to add support for more and more 

EnergyPlus objects. Besides low-level EnergyPlus 

inputs, we also imagine that developers will want to 

work toward a higher level interface for the plugin that 

makes energy simulation accessible to architects, 

engineers, and students. To borrow from SketchUp’s 

mantra “3-D for everyone,” the ultimate objective will 

be to provide “energy simulation for everyone.” The 

research question now becomes, “How do we best 

provide an easy-to-use interface for a complicated 

energy simulation program such as EnergyPlus?” 

CONCLUSION

The development of the Energy Design Plugin is an 

ongoing experiment in coupling an energy simulation 

engine to a commercially available 3-D drawing 

package via an API. As a prospect for integrating 

simulation into the earliest phases of the design 

process, the proposition carries benefits and risks. 

The plugin clearly benefits from SketchUp’s easy-touse 3-D GUI by saving us from developing this 

capability from scratch. The plugin also benefits from 

the extensive user base and popularity that SketchUp 

enjoys. Architects, a large segment of the SketchUp 

user base, are the users we want to reach during the 

design process. Finally, the plugin benefits from 

SketchUp’s unique role as a conceptual phase tool. 

The main risks associated with coupling to SketchUp 

arise because we have no direct control over the future 

of SketchUp or the SketchUp API. We are forced to 

develop the plugin within the constraints imposed by 

the API, including any limitations, missing features, 

and bugs. 

Tallying these benefits and risks, we suggest that the 

benefits are concrete and indispensable and the risks 

are hypothetical. There are no real technical barriers 

that cannot be overcome. Having come this far, we 

remain satisfied with our decision to couple EnergyPlus 

to SketchUp. 

ACKNOWLEDGMENT

This work was supported by the Building Technologies 

Program within the Office of Energy Efficiency and 

Renewable Energy at the U.S. Department of Energy. 

6 
7 

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Programmers’ Guide, Second Edition. The 

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1999. “Low-Energy Building Design—The 

Process and a Case Study,” ASHRAE 

Transactions, V 105, Part 2, pp. 802-810. Atlanta, 

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wxRuby. 2008. A Ruby wrapper for wxWidgets. 

 http://www.wxruby.org 
Figure 1 Opening an EnergyPlus input file for editing 

Figure 2 Editing an EnergyPlus zone 

8 
F1147-E(09/2007) 

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1. REPORT DATE (DD-MM-YYYY)

August 2008 

2. REPORT TYPE

Conference Paper 

3. DATES COVERED (From - To)

4. TITLE AND SUBTITLE

Energy Design Plugin: An EnergyPlus Plugin for SketchUp; Preprint

5a. CONTRACT NUMBER

DE-AC36-99-GO10337 

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

P.G. Ellis, P.A. Torcellini, and D.B. Crawley 

5d. PROJECT NUMBER

NREL/CP-550-43569 

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IGIN7100 

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National Renewable Energy Laboratory 

1617 Cole Blvd. 

Golden, CO 80401-3393 

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14. ABSTRACT (Maximum 200 Words)

This paper describes the Energy Design Plugin, a new software plugin that aims to integrate simulation as a tool 

during the earliest phases of the design process. The plugin couples the EnergyPlus whole-building simulation 

engine to the Google SketchUpTM drawing program. Leveraging the powerful SketchUp application programming 

interface, we developed a plugin that extends the capabilities of SketchUp to allow EnergyPlus building models to be 

developed in 3-D while taking advantage of all of the native SketchUp capabilities, including intuitive tools, different 

rendering modes, and realistic shading. The model geometry can be saved to create an EnergyPlus input file. 

Existing input files can be opened, edited in the SketchUp environment, and saved again. Already well-established 

as a popular tool among architects and designers, SketchUp offers a familiar, easy-to-use interface that, when 

coupled with the plugin, could make building energy simulation more accessible for architects, designers, and 

students during the design process. 

15. SUBJECT TERMS

energyplus; energy design plugin; sketchup 

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