Your place to find discontinued Lego technic sets and MOC Building Instructions.
In this folder you can find the libraries LPub3D uses:
C:\Users\[your user]\AppData\Local\LPub3D Software\LPub3D\libraries
Here you need to make sure the latest complete.zip is stored.
If you need non published parts available just copy/past those XX.dat files into the complete.zip file and restart LPub3D and voila the missing parts are visible and not anymore showing as ablack cube.
If you have sub parts consisting of a few parts and steps you can decide to move them to a call out. In below text it is briefly explained.
This is a way to reduce the number of pages of your building instruction or leave out the pages with just a small number of steps. Below an example of a sub part with just 10 parts and 2 steps.
When a Lego piece consists of separate parts like a minifig or universal joint. Besides the replace with the PLI BEGIN SUB statement here.
Continue reading Sub Assembly ‘Treat as Part’Sometimes it is difficult to show how parts need to be assembled in the existing model so far 
in building instructions.
This is how you can create this behavior in MLcad. Continue reading How to model parts ‘flying’ in to the sub assembly
With MLcad you can mimic the steps like in genuine Lego Building Instructions 
where you ‘marry’ two sub models build in two different sequences. See example on the right from set 42029 “Customized Pick up Truck” released in 2014.
Here is how you can accomplish this in ldraw.org MLcad. Continue reading Parts placed in a step to be moved in later step
Certain parts like shock absorbers or universal joints you like to place in your MOC in actual place
and configuration. As you can see in the example at the right the universal joint is bent in an angle. You do that by using the separate elements and place them in the required position. Problem is the final Parts list where you like this one 
to show up not the loose parts 
. Continue reading Replace sub parts with complete part for Bill of Materials
New parts list is made available by LDraw here. The most annoying point how to get these new parts visible in MLcad. This was the challenge because the rest is explained clearly, how to get the list installed or only the added parts via .exe installer or via Zip-file to add only those parts you like to add. Continue reading MLCad activate new parts list from LDraw