From Sketch to BIM and Back Again Using SketchBook Pro and ArchiCAD

Matthew Brewster
Founder and President, ARCHiDEAS

Building Information Modeling (BIM) is extremely valuable when it comes to producing documentation, analyzing structures and energy usage, and creating photo-realistic renderings for client presentations. However, it can be somewhat overwhelming when architects look to BIM as a design tool. 3D views can be great for confirming design decisions and details, but there is something to the input of the hand sketch that allows for visual thinking.

Master sketcher Frank Ching believes that while there are many methods to producing great design, the feedback of freehand drawing is an important tool. This is because sketching helps the designer to see the world in a different way and stimulates the imagination. Perhaps this is one reason why many architects resist the idea of using computer models for design. What would they say if we found a way to utilize the technology available today and incorporate the design input of hand sketching?

Will Computers Replace Paper?

We’ve heard this theory for many years, but paper hasn’t gone away yet. If anything, we have more paper flying around now than ever before. But as touchscreen technology becomes mainstream (thanks to the iPhone and now the iPad), this shift is opening the way for more natural computer interaction, getting us closer to the ideal of digital paper.

While touch-screen devices such as the iPhone are great for general computing, pen-enabled tablets are more appropriate for sketching. There are a variety of tablets and tablet-PCs currently on the market. But for the Mac-based architect, nothing beats the Modbook from Axiotron. It is a portable touch-screen computer featuring an acid-etched screen that replicates the feel of paper.

The figure above shows SketchBook Pro 2010 (a 2D drawing and drafting program from Autodesk) running on a Modbook. One of the best things about SketchBook is the interface. It is extremely clean and easy to use, which helps the architect focus on designing rather than the software they are using. Plus, you can use SketchBook very much like you would use a pencil and paper. Background grids are available to aid free­hand sketching, or you can use the built in straight-edge. (For an in depth review of SketchBook Pro, see this AECbytes article, Brainstorming with Autodesk SketchBook Pro.)

After an idea has been sketched out, how can we further develop the design? One solution is to bring our 2D drawing into SketchUp and start developing a 3D model. SketchUp is a good tool for quickly creating massing studies, as well as more detailed modeling. But why not start preliminary design models directly within a leading BIM application like Graphisoft’s ArchiCAD? ArchiCAD is a full-featured BIM application for modeling, rendering, drafting, detailing, layouting, and scheduling. Add-ons are available to further take advantage of the BIM model’s capabilities such as energy analysis and interference checking. Yet for all of its capabilities, ArchiCAD it is still very user-friendly.

Exploring ArchiCAD’s Interface

Cal State Fullerton professor and owner of Form:uLA Dimension Laboratories, Bryan Cantley believes that “interface equals interference.” Considering this opinion, one way to focus on the task at hand—in the design phase—is to configure the working environment for just the tool we need. In ArchiCAD, the Work Environment option lets you customize the interface, menus, shortcuts, etc., allowing you to use the application the way you want.

Here we’ve modified the Work Environment to show us just the tools we need for our design model in the Toolbox. Our Navigator (the palette used for moving around to different views) is set to Auto-hide. After we have moved to another view and start working, the Navigator moves out of the way. Some other useful interface features of ArchiCAD for quick, pen-based input are:

• Guidelines and Tracker: These allow for accurate angle input and feedback.
• Grid Snap: We can set the Grid Snap to 2”, making it quick to input accurate distances.
• Pet Pallete: This palette will pop up whenever you click on a selected element. It gives you quick access to editing commands.
• Contextual Menu: This “right-click” menu can be mapped to one of the two buttons on the stylus pen.

Continuing with the design, we’ll bring in our sketch to use as a background. In ArchiCAD, we’ll create a Worksheet where we can place our sketch. A Worksheet is a 2D view that can contain any data you need for reference. Go to the Documenting Tools in the Document menu, and Create an Independent Worksheet. For reference, we’ll call it “Background” and hit Create. Now we can bring in our sketch as an External Drawing. After placing the image, make sure that the scale is correct, using the Resize command if necessary.

Using the Navigator, we can move quickly from the Worksheet back to our Plan view. To see the sketch in this view, right-click on the Worksheet (in the Navigator) and select the Show as Trace Reference option. This virtual tracing-paper is a great way to coordinate and compare separate views. Note that ArchiCAD is the only BIM application that offers this feature. The Trace & Reference palette offers further control of placement and color.

With our sketch in the background we’ll use ArchiCAD’s Zone tool to start massing our design. Zones can be shaped in any way and display colors and materials. As BIM elements, they also contain data such as area, volume, or cost per sq ft. We’ll lay out the zones and then take a look at the model 3D. (Make sure Zones are checked to display in the View menu > Elements in 3D View > Filter Elements in 3D.) We can continue editing in the 3D environment using the pet palette. Clicking on a node offers “push/pull” editing.

As we continue editing our design in 3D and developing the massing, and once we are happy with the design, we will want to present this to our client. While computer models are accurate, they can look somewhat stale and lifeless. We have a few options to bring our model back to that hand-drawn, sketchy look.

Since ArchiCAD offers built-in sketch rendering, we’ll take a look at that first. Go to the Document menu > Creative Imaging > PhotoRender Settings. Choose Sketch from the available Engines. There are a variety of pre-set styles, or you can create your own look and feel. After you’ve configured the PhotoRender Settings, go back to the Document menu > Creative Imaging > PhotoRender Projection.

If color effects are desired, take a look at Piranesi from Informatix. More than just an effects’ filter, Piranesi offers tools for virtual 3D “painting.” Using Piranesi with a tablet-based interface is a very natural way to control brush strokes. From ArchiCAD, simply go to the File menu and Save As. Choose Piranesi file as the format and Save. Now open up the file with Piranesi. For more information about methods of rendering with ArchiCAD and Piranesi, visit the online training available at LearnVirtual.com.

Back to the Drawing Board

While these rendering solutions offer quality rendering effects, we may still need to continue with the design process. By saving the 3D model as a tiff image, we can go back to SketchBook and open up our 3D view. Place the 3D view on a background layer and continue sketching over the model.

Tablet-based computing offers a more direct, natural interface for sketching and modeling. But perhaps, even more important in the design process is the ability to move the design back and forth between different applications quickly and efficiently. This can be a reiterative process, starting with a sketch, layering it under a model, sketching over the model, and repeating until the solution is found. According to Bryan Cantley, the Cal State Fullerton professor quoted earlier, who also practices experimental architecture and tablet computing: “This process can open up new ways of seeing a design that may not be readily apparent with 2D drawing or 3D modeling only.” See one of his images below, and his blog at: http://form-ula.blogspot.com/

As touch-screen technology advances, we are likely to see tablet-based designing become more mainstream in architectural practice. While we might never get rid of paper completely, the stylus could become a new tool that progresses the discipline of architecture as well as the design process.

If you’re interested in furthering your knowledge on these topics, as part of your LearnVirtual membership, you’ll have access to recorded eClasses focused on sketch and photo rendering techniques, plus over 110 other recorded eClasses on a wide range of topics including modeling techniques, drafting techniques, process management, revision management and design review. Also, new LIVE eClasses occur each week! To learn more about LearnVirtual, go to www.learnvirtual.com.

About the Author

The founder and President of ARCHiDEAS, Matthew Brewster is one of the preeminent ArchiCAD instructors in North America. Based in Seattle, his background is in architecture and construction. In addition to serving as an occasional instructor for the LearnVirtual online training program, he offers ArchiCAD training and BIM consulting services for the Seattle area and the Pacific Northwest. For over 10 years, Matt has focused on solutions for the AEC market and has helped a wide range of firms transition to new technologies. Please visit www.archideas.biz for more information.

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