Official Library Specifications and Part Number Spec

[Travis Cobbs]

Discussion seems to have petered out on this 2 docs:

Official Library Part Number Specification
LDraw.org Official Parts Library Specifications

I did a proofread a few days ago and they're pretty much ready to go I think. 

I'll follow this thread and make any change you 3 propose. I'd like to finish this project out.

I'd like to refrain from providing input on the parts number spec. I don't feel I have enough knowledge of it to be qualified to make good decisions. I'm happy to go along with whatever Chris and/or Roland decide regarding it.

In the other spec, I found a few things I disagree with (although none is critical):

While both upper and lower case letters are permitted in filenames, filenames are case-insensitive. Currently, all official parts are issued with upper-case only names.

I feel that we should enforce upper case filenames to avoid confusion, but this is a fairly minor preference on my part. I'm willing to let it stand.


I don't understand why this is allowed:

Part (but not all) of a conditional line (line type 5) may overlap all (but not part) of a line (line type 2). Consider the line A-B-C-D

If AB and CD need to be conditional lines and BC a line, it is acceptable to define this as a line BC and a single conditional line AD
If AC needs to be a line and just CD needs to be a conditional line, it is not acceptable to define the conditional line as either AD or BD
If AD is a line, there are no valid conditional lines along the length of AD

I understand what it is saying, but I don't understand why it is allowed. Note: if we keep this section as-is, we need to add a colon to the end of the first line, and periods at the end of each of the other lines.


I think the following section should be amended:

Every effort must be made to remove overlapping co-planar polygons (line type 3 or 4). Where overlapping polygons are unavoidable, the overlap must be kept to the absolute minimum.

It should have an extra qualification:

Every effort must be made to remove overlapping co-planar polygons (line type 3 or 4). Where overlapping polygons are unavoidable, the overlap must be kept to the absolute minimum. Also, the overlapping polygons must be the same color.

Do we want to clarify that BFC NOCLIP is allowed (particularly for decorations printed on transparent parts)?


I also found a bunch of typos:

These rules have evolved over time and there may be files in the Official Library that do not conform to these rules.

Should be:

These rules have evolved over time, and there may be files in the Official Library that do not conform to these rules.

(Add required comma.)

(To avoid confusion with English grammar, comma is not a permitted character.)

Should be:

(To avoid confusion with English grammar, comma is not a permitted character.)

(Capitalize sentence, and move period inside parentheses.)

hi-res

I would prefer if this were updated:

high-res

(Using "hi" to mean "high" in this context is quite common, but it bugs me.)

(ie 1.5 not 1.500)

Should be:

(ie 1.5, not 1.500)

(Add comma. Note: see below about "ie".)

(ie 1.5 not 01.5)

Should be:

(ie 1.5, not 01.5)

(Add comma. Note: see below about "ie".)

non-conplaner vertices

Should be:

non-co-planar vertices

(Fix spelling. Also, since most of the rest of the document uses "co-planar" and not "coplanar", I added the optional dash. Given that this looks odd here, and given that both "coplanar" and "co-planar" seem to be equally correct, we might consider updating all instances of "co-planar" in the document to be "coplanar". We do want to be consistent.)

To prevent co-linear vertices in quads/triangles and concave quads every interior angle in a quad or triangle must not be greater than 179.9 degrees or smaller than 0.025 degrees.

Should be:

To prevent co-linear vertices in quads/triangles and concave quads, every interior angle in a quad or triangle must not be greater than 179.9 degrees or smaller than 0.025 degrees.

(Add comma.)

A quad considered coplaner if it is split into two triangles and both triangles are co-planar with each other.

Should be:

A quad is considered co-planar if it is split into two triangles and both triangles are co-planar with each other.

(Add "is", and fix "co-planar".)

There two ways to split a quad into two triangles and both must result in co-planar triangles.

Should be:

There are two ways to split a quad into two triangles, and both must result in co-planar triangles.

(Add "are". Add required comma.)

The triangles are considered co-planar if the angle between their surface normals is less than or equal to 3 degrees, however, an angle of less than 1 degree is required unless justification is given by the part author.

Should be:

The triangles are considered co-planar if the angle between their surface normals is less than or equal to 3 degrees. However, an angle of less than 1 degree is required unless justification is given by the part author.

(Split sentence into two sentences.)

This especially true for large quads where the "warp" can be seen at normal viewing magnifications.

Should be:

This is especially true for large quads where the "warp" can be seen at normal viewing magnifications.

(Add "is".)

See Official Library Part Number Specification for shortcut part number rules

Should be:

See Official Library Part Number Specification for shortcut part number rules.

(Add period.)

For assemblies without moving parts, it's simple: all parts composing the assembly are ~, and an assembly shortcut is provided (several shortcuts may be needed to account for different colour combinations).

Should be:

For assemblies without moving parts, it's simple: all parts composing the assembly are ~, and an assembly shortcut is provided. (Several shortcuts may be needed to account for different colour combinations.)

(Make parenthetical phrase a separate sentence.)

Examples include hoses, ropes, strings, springs, fabrics, rubber bands and platic sheets

Should be:

Examples include hoses, ropes, strings, springs, fabrics, rubber bands and plastic sheets.

(Add period, and correct spelling of "plastic".)

decrete

Should be:

discrete

This places them in the shortcut category and thier descriptions will follow the rules outlined for shortcuts (i.e. use of the "~" character)

Should be:

This places them in the shortcut category, and their descriptions will follow the rules outlined for shortcuts (i.e. use of the "~" character).

(Add required comma and period, and correct spelling of "their".)

Flexbible

Should be:

Flexible

Subsquent formed versions shall have a suffix added to the part number as specified in the Official Library Part Number Specification

Should be:

Subsequent formed versions shall have a suffix added to the part number as specified in the Official Library Part Number Specification.

(Add period, and correct spelling of "Subsequent".)

See Official Library Part Number Specification for sticker number rules

Should be:

See Official Library Part Number Specification for sticker number rules.

(Add period.)

where 1 stud = 20LDraw units

Should be:

where 1 stud = 20 LDraw units

(Add space.)

If the sticker is designed to be placed on the curved surface of a part or folded around the edge of a part a ‘formed’ version of the sticker part may be modelled in addition to the flat version.

Should be:

If the sticker is designed to be placed on the curved surface of a part or folded around the edge of a part, a ‘formed’ version of the sticker part may be modelled in addition to the flat version.

(Add comma.)

See Official Library Part Number Specification for sticker shortcut part number rules

Should be:

See Official Library Part Number Specification for sticker shortcut part number rules.

(Add period.)

The shortcut may not include more than one part, although that part can be a composite part (one with a "c" in the filename).

Should be:

The shortcut may not include more than one part, although that part may be a composite part (one with a "c" in the filename).

(Change "can" to "may".)

Sticker shortcuts that do not conform to this rule can remain in the Official Library and not be made obsolete

Should be:

Sticker shortcuts that do not conform to this rule can remain in the Official Library and not be made obsolete.

(Add period.)

See Official Library Part Number Specification for patterned part number rules

Should be:

See Official Library Part Number Specification for patterned part number rules.

(Add period.)

Since this printing is easily removed and LDraw parts can come in any variety, all patterned parts should based on another plain, unpatterned part in the library. This means that a plain version of the patterned part should created even if plain version has never been produced by LEGO.

Should be:

Since this printing is easily removed, and LDraw parts can come in any variety, all patterned parts should be based on another plain, unpatterned part in the library. This means that a plain version of the patterned part should be created even if a plain version has never been produced by LEGO.

(Add required comma. Add "be" twice, one before "based", the other before "created". Add "a" before "plain".)

<base part description> is the description of the non-patterned version of the part

Should be:

<base part description> is the description of the non-patterned version of the part.

(Add period.)

Errors in either one of these !KEYWORDS entries should not be cause for a hold vote on the Parts Tracker since this is simply data to make locating specific patterns easier

Should be:

Errors in either one of these !KEYWORDS entries should not be cause for a hold vote on the Parts Tracker since this is simply data to make locating specific patterns easier.

(Add period.)


Finally, some general observations:

One "etc" in the document has a period after it, while the other two don't. I believe that proper grammar requires the period, but if you don't like how that looks, the three should be consistent. Similarly, "ie" is used in a number of places without periods, and in one place with periods ("i.e."). I prefer all to have periods, but the document should be consistent.

The document is inconsistent in its use of the Oxford comma. I personally someone who favors its use, but I am willing to allow the document to go either way. However, it does need to be consistent.

The document is also inconsistent in its use of smart quotes. I think it should either always use them (except in any LDraw file examples) or never use them.