Inclusion of Helper parts in the Official LDraw Parts Library

[Willy Tschager]

The Steering Committee has voted for the inclusion of helper parts in the Official LDraw Parts Library. As helper parts have to go through the LDraw Parts Tracker via "Fasttrack" for the inclusion in the package, this won't happen in a timely fashion as the current PT is technically not ready. However we agreed on the following specs:

Helper Part General Rules

Helper parts are non-LEGO text, arrows, and other icons intended to be used in building instructions or other renderings. In some cases these parts can be used to position non-brick elements (such as lights) in a LDraw scene.

Helper parts will not be subject to review on the Parts Tracker and will qualify for admin "fast tracking".

Helper Description

As for the third party parts it starts with '|' or '~|'

    |Helper <2D/3D qualifier> <Type> <additional description> <lenght/height/depth>

<Type> Arrow, Dot, Line, Letter, Number, Light, LSynth Constraint, String Knot ...
<additional description> Straight, Rotation, "3", "F", Vertical
<lenght/height/depth> 2L, 3 Studs, 20 LDU, 10 mm

Helper Part Numbering

Name as description without blanks: Helper3DEasyRotation.dat

Helper Category

Not needed. From the !CATEGORY and !KEYWORDS spec: If a part has no !CATEGORY meta-statement, the category is assumed to be the first word in the part name (ie. the first word of the first line of the part file).

Helper Keywords

Not needed, as the description should contain all relevant information.

Helper Location

<Library Root>\parts\helper

Helper Dimensions

Numbers and letters should fit into a x-z grid of a: 20 x 20 LDU

[Magnus Forsberg]

Helper Category

Not needed. From the !CATEGORY and !KEYWORDS spec: If a part has no !CATEGORY meta-statement, the category is assumed to be the first word in the part name (ie. the first word of the first line of the part file).

I don't question this decision, but I don't understand this bit. Maybe it could be explained?

I'm thinking like this:
Why do we have a list of categories? - It is to be able to sort all descriptions that do not start with a specific word.
Which words are specific? - The words that are in the list of categories.
Doesn't that mean that if the first word is not in the list of categories, a category from the list must be selected?
The word Helper is not included in the list of categories.

[Travis Cobbs]

I don't question this decision, but I don't understand this bit. Maybe it could be explained?

I'm thinking like this:
Why do we have a list of categories? - It is to be able to sort all descriptions that do not start with a specific word.
Which words are specific? - The words that are in the list of categories.
Doesn't that mean that if the first word is not in the list of categories, a category from the list must be selected?
The word Helper is not included in the list of categories.

I believe that the intent behind the category list is to prevent parts from being in new categories without prior approval. I don't think that is enforced by the PT right now. Official parts definitely have categories that aren't in the list in the Category spec. The following categories exist in official parts (either via their name or via !CATEGORY) that aren't on the list:

• Duplo
  
• Roof
  
• Pov-RAY
  
• String
  

Additionally, "Propellor" (a mis-spelling of "Propeller") also exists, but that is being fixed. Pov-RAY is only used in light.dat, which was created by James Jessiman. It's probably reasonable for it to not be on the list of approved categories, since I doubt that we want any more such files.

The following categories are on the allowed list, but don't show up in any official parts:

• Constraction Accessory
  
• Forklift
  
• Grab
  
• Lever
  

Note that as far as I know, the category list isn't designed to be used by any LDraw-compatible software. So if a part doesn't have a !CATEGORY meta-statement, the first word in the part name is its category. If it has a !CATEGORY statement, that is its category. From the point of view of LDraw-compatible software, that's it. There is no other list.

I wouldn't expect Helper to be on the allowed list until the PT is ready to accept helper parts.