Minimum System Requirements for PC
Operating system: Windows XP, Windows Vista or Windows 7.
CPU: 1 GHz processor or higher
Graphics card: 32 MB graphics card (OpenGL 1.1 or higher compatible)
RAM: 512 MB
Hard Disk Space: 100 MB
Minimum System Requirements for Mac
Operating system: OS X 10.4 or higher
CPU: Intel processor or faster processor
Graphics card: NVidia GeForce 5200/ATI Radeon 7500 or better (not integrated)
RAM: 1 GB
Hard Disk Space: 100 MB
LEGO Digital Designer version 3.1 is not available on PowerPC Macs. To allow PowerPC users access to their models, we have made a special version of 2.3.20 available exclusively for that architecture. This version will not support the option of buying through Design byME, and it is not supported by LEGO. It can be downloaded here: LDDMacInstaller.zip
Issue running LDD on Mac OS X 10.4
A sound error can occur in OS 10.4 which prevents LDD from running. This issue can be fixed by downloading and installing a patch, which can be downloaded here
Disclaimer
The LEGO Group of companies (LEGO) is providing LEGO® Digital Designer 3 (the Software) at no charge. Any commercial use of the software is strictly prohibited. The entire risk arising out of the use or performance of the software remains with you. The software is provided as-is without any warranty of any kind. The entire risk arising out of use or performance of the software remains with you. To the maximum extent permitted by applicable law, in no event shall the LEGO Group of Companies (including LEGO Systems A/S) and its suppliers and licensors, be liable for any damages arising out of the use or inability to use the software. To install and use the software, you must agree to the terms of the LEGO Digital Designer 3 License Agreement included with the software. Please be sure to read the License Agreement before installing LEGO Digital Designer 3 on your system.
