To install the LDraw library for Mac, please follow the steps below:
1) Go to http://www.ldraw.org/help/getting-started.html and click on 'Step by Step installation instructions for Mac OS'.
2) After that click on ''Download and install LDraw package' and then finally click on 'Download complete.zip'. A complete .zip package will be downloaded, unzip the folder to access its contents
3) Open the Virtual robotics Toolkit, click on the 'File' menu and select 'Preferences'. Click on the 'Path' tab and browse the path for your LDraw package folder.
4) Click on the Help menu and select 'Patch Lego Digital Designer'.
5) Finally, export your model as an LDraw file in LEGO Digital Designer and then import it into the Virtual Robotics Toolkit simulator.
For further questions regarding LDraw for Mac, please contact firstname.lastname@example.org.