Best Free Lego Building Software


Lego was the classic brick building toy of yesteryear. Nowadays, it's moved in all sorts of technological directions, including elaborate Mindstorms; robotics based on programmable bricks originally conceived for educational purposes, and something approaching computer aided design (CAD).

Without pretending to compete with the feel of the real thing, there's Lego building freeware out there that's just crying out to be used as a virtual toy.

Fancy clicking some virtual bricks together on your PC? Over the years, the Lego toy brand has become increasingly oriented towards prebuilt models making it more difficult to think outside the predesigned blocks. But on a computer you can let your fantasy rip without having to shell out for designer components. And Lego building programs are a spatially intriguing experience for youngsters of all ages.

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Lego Digital Designer in build modeLego Digital Designer (LDD) is the official Lego CAD-like program for Windows and Mac. For many this smart toy will be a clear first choice. The graphics and controls are excellent. If you're accustomed to Google Earth, then you'll probably soon feel at home navigating in 3D on the virtual grid, moving building blocks and turning them through 90 degrees.

A child-friendly user manual is provided, and there’s also a series of brief video tutorials on the LDD site to help you get started. The company does try to attract you towards their product range. But it's easy enough (for an adult at least!) to go one's own way.

In 'Build mode', there are lots of tool options and other stuff to explore. You can save your new Lego constructions as you go. It's also fun to take prebuilt models to bits, and of course you can also reconstruct them or dream up your own creations with Mindstorms components. However, even if you own a physical Mindstorms set, scope for serious design is limited by LDDs inability to rotate pieces through any angle.

Switch to 'View mode' to see your constructions against several different backgrounds (with sound effects), such as the sea or outer space. You can get the whole construction to explode in a flash... and then gently drift back together again. You can also take screenshots on the fly. There's now also the possibility to upload and share your LDD creations over the Internet, though you have to comply with certain brick choice restrictions (for example, my illustrated attempt didn't pass the test).

It's up to you to mix the build and thrill. For some children, this free toy might be a fun first step towards the  world of creative 3D computer graphics and CAD.


BlockCad Leggo like building programBlockCad is unofficial ‘Lego-like’  freeware. So the program is completely free from advertising material. BlockCad has been in development since 1998 when the Swedish programmer built it for his own children. Unsurprisingly, it has a less up-to-date look and feel than the commercially backed Lego Digital Designer and a slightly less extensive choice of building blocks and joins.

Nevertheless, BlockCad has a stimulating set of building options (you can save your work) and the interface is fairly intuitive to use despite a relative lack of text. There are plenty of hotkeys and a schematic user manual is provided, but expect a learning curve. You can display your work against any background image file of your choice.

All in all, BlockCad is a remarkable individual achievement and may be the Lego-like program of choice for less powerful computers.


More advanced Lego freeware:  Any Lego fan with an interest in CAD will probably want to check out LDraw in conjunction with LeoCAD and perhaps also MLCad (LDraw download links here).

The independent LDraw community project (recognized by Lego) provides a large collection of freeware tools for serious modeling, design and imaging. LDraw is also partially compatible with Lego Digital Designer. So it's an obvious step up for computer modeling. But it's more than a simple toy. LDraw and LeoCAD could be the way to go for Mindstorms enthusiasts wanting to construct programmable digital designs.

These lego-like CAD freeware programs run on Windows 98 and above (32-bit), Mac and Linux. Mac users may also like to check out Bricksmith.


To be reviewed: SR 3D Builder (Windows only) is an ambitious Lproofreadego design freeware project which is currently under development - think beta testing. The brainchild of an Italian enthusiast, SR 3D Builder should be worth watching as it develops. Use of LDraw suggests that SR 3D Builder may have potential for some quite advanced capabilities. The documentation is extensive, with a growing user manual in reasonably comprehensible English; video tutorials are also available, but the high speed and absence of voice over makes them awkward to follow. One for Lego software enthusiasts to explore? 

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Quick Selection Guide

Lego Digital Designer

Gizmo's Freeware award as the best product in its class!

Runs as a stand-alone program on a user's computer
Good 3D graphics, intuitive controls, advanced building options, upload and share online
Many commercial aspects, large download, resource hungry
185.04 MB
Unrestricted freeware
German language option, user manual
Windows XP, Vista, Win 7; Mac version also available.


Runs as a stand-alone program on a user's computer
Lightweight 'Lego-like' program, many building options, use own backgrounds (image files), no commercial affiliation
Less modern user interface, learning curve, development has slowed down
828 KB
Unrestricted freeware
Instructions also available in French and Spanish. v3.18 released 4 January 2005
Windows 95 to XP, also works on Vista 32 bit.

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This page is about: lego building program, lego builder, lego building games, lego construction program, lego freeware, lego cad, lego digital design

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