Sunday, December 18, 2011

Lego Digital Designer

After I posted the previous entry about modeling the synchro drive in SR 3D Builder, I decided to try doing it in Lego Digital Designer.

  • Good: I love the way axles and pins just snap into holes, and vice versa. Much easier than either SR 3D or MLCad. The current version of SR 3D ( has a feature called "automatic brick orientation" which offers a similar ability, but it's still marked as experimental, and doesn't feel as snappy as LDD's.
  • Good: Pan, zoom, and orbit control with the mouse is just like Google Sketchup. In contrast, SR 3D requires you to use a slider to zoom, and I haven't figured out the pan controls yet. (Update: hold down the middle button or both left and right mouse buttons at the same time.)
  • Good/bad: Collision detection is very good, but can be intrusive. It won't let you drop a piece where it intersects with another.
  • Good/bad: The building guide was easily generated. The building guide is also animated, and can be rotated and zoomed. But it created structures which will not fit without some disassembly.
  • Bad: without a pin in place, the software could not figure out where to put a studless beam.
  • Bad: Limited selection of parts and colours. For example, the 1/2 thick triangle shaped beam only comes in grey, red or black. In my personal collection, I have this item in blue, from an old Star Wars set. In the other programs, there is a wider selection of colour and even transparencies. I really enjoyed the fact that I could make the turntable a light transparent blue. It's such a large piece that leaving it all black makes the other pieces harder to see.
  • Bad: The division of parts into themes seems unnecessary.
  • Bad: The 12-tooth bevel gear is filed under the "Extended" theme, as a "conical wheel, z12". It does not show up searching for "bevel" or "gear". It's also only available in red
  • Bad: Bevel gears have a problem fitting. Couldn't figure out a solution to this one.

Here's what I was able to do. It was pretty easy to throw it together because of how easily pins and axles just fall together. But I had to leave out one of the bevel gears, and substitute a cross thingy for the 3482 wheel.


  1. Hi,
    I'm the author of SR 3D Builder and it seems you are talking about my software here... :-)

    I just want to make a little note:
    It is absolutely TRUE that LDD user interface can be better than SR3DBuiler one, but when building complex technic models you will discover its limits, especially when you need to place a pin or an axle in little space: you cannot set the height of pin or axle insertion point, resulting in very difficult parts displacement. Another thing is that a pin or axle snap, but do not auto-rotate to final connection orientation. Furthermore in LDD you cannot disable this feature, and putting gears link together requires exact gear rotation to avoid parts penetration.

    Other issues with LDD?
    - try making an even simple rotation with a 2000 part model: you get stuck with it.
    - try animating 2 simple gears: you cannot
    - try building anything with shock absorber or linear actuator: you cannot! parts does not exists!!

    well... enjoy LDD now


  2. Forget a little thing:
    to zoom in or out, press CTRL and use mouse wheel.

    About the user interface: it is designed to be used for a normal 2 hands human:
    - one for the mouse
    - the other for the keyboard

    You need a bit to get used with, but it will beby far faster than LDD one (IMPO)