Purpose

The Official Model Repository (OMR) is a database of files in the LDraw File Format describing models that are released as sets by LEGO®.

For consistency between models and ease of indexing by software, a standard for the file headers, names, and hierarchy in the OMR is needed. This document will outline the extra requirements (in addition to those set forth in the current LDraw File Format specification) for a model to be included in the OMR.

Base Requirements

All files in the model will conform to the current LDraw File Format.

Base File Naming

Each model in the OMR will consist of several files that are packaged together into a single MPD file. For sets that include instructions for multiple models, each model will have its own MPD file. Each MPD for the set will be named in the following manner:

<Set Number> - <Set Name>[ - <Sub Model Name>]

Where:
<Set Number>: The number assigned on the container of the set.
<Set Name>: The name of the set printed on the container in English.
<Sub Model Name>: This is Optional in most cases. This is required for alternate models that are detailed in instructions (e.g. the Creator theme). In this case the naming is left to the discretion of the author but should be descriptive of the model contained in the MPD.

For playsets or other sets where there are multiple models that are part of an integral whole, all of the submodels will be contained in one MPD.

Example:
The creator set 4896 - Roaring Roadsters has 3 models in the instructions:
4896 - Roaring Roadsters - Roadster.mpd
4896 - Roaring Roadsters - Dragster.mpd
4896 - Roaring Roadsters - SUV.mpd

MPD File Structure

The MPD will conform to the MPD File Specification.

Each filename will have the structure:
<Set Number>[ - <Optional Qualifier>] - <Individual filename>

Where:
<Set Number> is the the number printed on the model's container.
<Optional Qualifier> is a sequential number, starting with 1, added if there is more than one set that could be assigned <Set Number>.
<Individual filename> is up to the discretion of the author with the following guidance:

• A logical naming scheme is highly desired.
• Each individual model in the set (e.g. a vehicle or minifig) shall have its own separate file inside the MPD.
• Minifig file name should have the name of the character, if known.

Unofficial parts are allowed to be used. The filename of the unofficial part is subject to the following naming rules:

<Set Number>[-<Optional Qualifier>] - <Unofficial Part Number>.dat

<Set Number> is the the number printed on the model's container.
<Optional Qualifier> is a sequential number, starting with 1, added if there is more than one set that could be assigned <Set Number>.
<Unofficial Part Number> is the unofficial part number assigned in that very moment.

Example:
33956.dat would be renamed to 3345 - 33956.dat or 3345-1 - 33956.dat.

It is highly encouraged that any parts created for use in an OMR file be submitted to the LDraw.org Parts Tracker.

If a part is unavailable either officially or on the LDraw.org Parts Tracker, a suitable substitution may be made. If the unavailable part is a patterned part with an unpatterned version available, use the unpatterned version. A comment should be inserted stating that a substitution has been made or, if no substitution is available/suitable, that a piece has been omitted. Reference the step and page number of the instructions if possible.

Example:
0 // The next piece should have the Star Wars Hatch pattern per step X on page Y or
0 // Bionicle piece X should go here per step Y on page Z

File Headers

Each individual model file in the MPD that does not represent an unofficial part must have the following standard header format.

Standard Header:
0 FILE <Filename>.ldr
0 <Individual filename>
0 Name: <Filename>.ldr
0 Author: <Author Name> [Username]
0 !LDRAW_ORG Model -OR- 0 !LDRAW_ORG Unofficial_Model
0 !LICENSE Redistributable under CCAL version 2.0 : see CAreadme.txt

0 !THEME Theme name
0 !KEYWORDS words, more words, …,
0 !KEYWORDS words in second row, …, final words

0 !HISTORY YYYY-MM-DD [Username] Free text description of change. This can wrap to a
0 !HISTORY YYYY-MM-DD [Username] second row with the same date if necessary. However authors should lean toward writing longer
0 !HISTORY YYYY-MM-DD [Username] single !HISTORY lines(and not feel constrained to the historic 80-character limit on line length).

Where: <Filename>: The name of the file using the rules specified in the MPD File Structure section
<Individual filename>: The name of the individual file using the rules specified in the MPD File Structure section
<Author Name>: The name of the author. Real full names (first and last) are required by the LDraw.org Contributor's Agreement
[Username]: The LDraw.org username of the author
Optional commands are !THEME, !KEYWORDS, and !HISTORY

Example:
0 FILE 4896 - Roadster Main.ldr
0 Roadster Main
0 Name: 4896 - Roadster Main.ldr
0 Author: Joe Smith [jsmith]
0 !LDRAW_ORG Unofficial_Model
0 !LICENSE Redistributable under CCAL version 2.0 : see CAreadme.txt

0 !THEME Creator
0 !KEYWORDS car, convertible

0 !HISTORY 2011-08-01 [jsmith] Initial creation

Each individual model file in the MPD that represents an unofficial part must use the standard header format of unofficial parts on the parts tracker. Its 0 FILE entry will reflect the modified MPD version of the part's filename, but the rest of the header will reflect the original filename.

META commands

All META commands are allowed in the model file but not specifically required except as specified for the header. If included, any META commands used should enable any instructions generated to be as close to the official instructions as possible.

Mirrored geometry

Models with bilaterally symmetric sections can often be modeled much more easily by modeling one half of the symmetric section and then including it in the model twice, with one instance mirrored around the symmetry line. Unfortunately, this mirroring produces an incorrect parts list, and also produces a mirrored LEGO logo on the model's studs when rendered with certain software, so using mirroring is strongly discouraged.