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Stardate 2011.07.12 (Tuesday) - Working with Lego Digital Designer

posted Aug 17, 2011, 9:40 AM by Anant Narayanan

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The first order of business is to download and install a CAD (Computer-Aided Design) program for the second phase of the Moonbots Competition.  While the competition does not specify the CAD program to be used, the obvious one to use is the LEGO Digital Designer program, available as a free download from LEGO.  The latest release of the program is Version 4.1.7.  If you have an earlier program, please upgrade to the latest version – it appears to be much more stable.

You can download LEGO Digital Designer at  The download is pretty large (approx. 126 MB), but should not take more than few minutes on a broadband connection.  The current download version is 4.1.7.  On my computer, I upgraded from LDD 3.1.3 to LDD 4.1.7.

If any of you have technical difficulties in downloading and installing the program, please let me know ASAP.  I am happy to assist you with technical gremlins.

After the program is downloaded, first select Mindstorms tab -- rather than the DesignByMe or LEGO Universe (was Creator in LDD v.3.1), the other two options. Next, please click on the plus sign on the lower right center to chose the "Free Build" option (if you were reopening a prior design, you would chose the other button next to this, and navigate the appropriate *.lxf file).

This should give you a relatively clean work area, with left and right side panels.  The right subpanel can be safely closed (it invites you to go to the website).  The left subpanel has a collection of parts, organized into 13 groups, each of which can be expanded by clicking on the plus sign in each of the 13 tiles).  You can find a help file/tutorial in the Help Menu Group on the top left.  There are four arrows on the design board for rotating the object being built along the z- and x axes.  There are also two buttons for zooming in and out (+ and -) next to the bottom arrow.  Start out by playing with the program.

The homework for today is to spend about a couple of hours building something real and depicting it with LDD.  It would be even better if each team member builds something physical with LEGO parts (the newer pin and beam type, rather than the old-style LEGO bricks), and recreates it in LEGO Digital Designer.

Rohit's Geared Spinner

Today, Rohit and I worked on recreating a geared spinner that we had designed for his science fair.  The LDD design file is attached for reference. It took him about three hours to put this together -- most of the work was in figuring out how to get the gears to mesh -- we had to use the hinge tool to make it work.  You are not required to try anything as complicated -- keep the basic physical design simple, so that it can be portrayed easily in the CAD program.

Good Luck with LDD.

Anant Narayanan,
Aug 17, 2011, 9:58 AM