What's the right number for my part?
For more information about part numbering, see the Official Library Part Number Specification.
What's the right number for my patterned part?
What are 'primitives'?
Please see the Primitives Reference.
What are 'subparts'?
Generally, subparts are LDraw files created for repeating structures in parts. For example, if you create a Tile 2x2 with a new top pattern you can use the corresponding subpart, s\2068s01.DAT (it doesn't have a top face). So you only have to create the top face by yourself and then reference to the subpart for the rest of the part. This saves a lot of time and space.
What's the right format for a part file?
What are !CATEGORY and !KEYWORDS?
Please see the !CATEGORY and !KEYWORDS Language Extension.
What is BFC?
Back Face Culling is a way for graphics programs to speed up rendering, by quickly discarding surfaces which are facing away from the viewer. LDraw's syntax doesn't support BFC operations. With some formatting rules and a few additional meta-statements, part files can support BFC-capable renderers. For more information about BFC, see Back Face Culling (BFC) Language Extension.
What is the CMDLINE meta-statement?
CMDLINE was once used as a way to specify the 'default' color of a part when a new part was placed in the original LEDIT program. It has since been made obsolete and is not used in new, official parts. Exisiting library part may contain this meta statement which is not an error and only exists as a kind of formalized comment about the part itself.
How do I get my part into the Official Library once I'm done
The Parts Tracker is where new parts are evaluated for inclusion into the Official Library. For more info on the Parts Tracker and how to submit your part see the Parts Tracker FAQ