Minor changes to the Official Library Spec


Minor changes to the Official Library Spec
#1
Based on feedback, I'd like to proposed a few minor changes to the Official Library Spec:

Clarification to Sticker Geometry:
- For stickers printed on a transparent medium, the type 1,3, or 4 lines that comprise the pattern shall be preceded by a 0 BFC NOCLIP statement and ended by a 0 BFC CLIP statement
- The pattern should be oriented such that the top of the pattern aligns with the +Z axis. Exceptions to this rule may be made on a case by case based.

Claification to Sticker Shortcuts:
- Require a !KEYWORDS entry with text similar to Pattern !KEYWORDS Entry:
A sticker shortcut should, at a minimum include at least one !KEYWORDS entry in the form of Set <set number> where <set number> is the number of an official LEGO set in which that pattern appears. Only one set need be listed but more can be if desired.[/b]
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RE: Minor changes to the Official Library Spec
#2
(2021-04-26, 20:50)Orion Pobursky Wrote: Based on feedback, I'd like to proposed a few minor changes to the Official Library Spec:

Clarification to Sticker Geometry:
- For stickers printed on a transparent medium, the type 1,3, or 4 lines that comprise the pattern shall be preceded by a 0 BFC NOCLIP statement and ended by a 0 BFC CLIP statement
- The pattern should be oriented such that the top of the pattern aligns with the +Z axis. Exceptions to this rule may be made on a case by case based.

Claification to Sticker Shortcuts:
- Require a !KEYWORDS entry with text similar to Pattern !KEYWORDS Entry:
A sticker shortcut should, at a minimum include at least one !KEYWORDS entry in the form of Set <set number> where <set number> is the number of an official LEGO set in which that pattern appears. Only one set need be listed but more can be if desired.[/b]

I approve, with a minor change to the second proposal: "... in which that pattern appears." --> "... in which that sticker appears."
Chris (LDraw Parts Library Admin)
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RE: Minor changes to the Official Library Spec
#3
(2021-04-26, 20:50)Orion Pobursky Wrote: Clarification to Sticker Geometry:
- For stickers printed on a transparent medium, the type 1,3, or 4 lines that comprise the pattern shall be preceded by a 0 BFC NOCLIP statement and ended by a 0 BFC CLIP statement

Why should we be forced to add a BFC NOCLIP in all stickers on a transparent medium?
I can see a need if the transparent sticker is intended to be on a tranparent part, like a glass window, but not if it's only used on solid coloured bricks. If the idea is that a user might want to have any sticker on a transparent part visible from behind, then why don't we have all patterns, on all parts, in a BFC NOCLIP? I don't see why a print on a transparent sticker should be treated differently than a printed brick.

(2021-04-26, 20:50)Orion Pobursky Wrote: - For stickers printed on a transparent medium, the type 1,3, or 4 lines that comprise the pattern shall be preceded by a 0 BFC NOCLIP statement and ended by a 0 BFC CLIP statement

Does this mean that the unprinted top surface is not allowed to be within the BFC NOCLIP section?
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RE: Minor changes to the Official Library Spec
#4
(2021-04-27, 16:32)Magnus Forsberg Wrote: If the idea is that a user might want to have any sticker on a transparent part visible from behind, then why don't we have all patterns, on all parts, in a BFC NOCLIP?

I'm not a fan of the proposed rule as I think it is too use specific but it was requested to I added it.

I also had the same thought as above. One of the major points of LDraw is that parts can be in any color. Maybe we should update parts as they are recycled. Or, better yet, just revise the BFC spec so that non-color 16 and 24 lines are excluded from BFC (actually, now that I think about it, that might be too broad).

I'm willing to live with a small quirk of rendering for the sake of simplicity.
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RE: Minor changes to the Official Library Spec
#5
(2021-04-27, 16:32)Magnus Forsberg Wrote: Why should we be forced to add a BFC NOCLIP in all stickers on a transparent medium?

To be in sync with the specs for patterns on transparent parts and not have yet another exception of a general rule?

w.
LEGO ergo sum
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RE: Minor changes to the Official Library Spec
#6
(2021-04-26, 20:50)Orion Pobursky Wrote: Based on feedback, I'd like to proposed a few minor changes to the Official Library Spec:

Clarification to Sticker Geometry:
- For stickers printed on a transparent medium, the type 1,3, or 4 lines that comprise the pattern shall be preceded by a 0 BFC NOCLIP statement and ended by a 0 BFC CLIP statement
- The pattern should be oriented such that the top of the pattern aligns with the +Z axis. Exceptions to this rule may be made on a case by case based.

Claification to Sticker Shortcuts:
- Require a !KEYWORDS entry with text similar to Pattern !KEYWORDS Entry:
A sticker shortcut should, at a minimum include at least one !KEYWORDS entry in the form of Set <set number> where <set number> is the number of an official LEGO set in which that pattern appears. Only one set need be listed but more can be if desired.[/b]

Since there were no more comments for 3 months it should be added to the specs.

w.
LEGO ergo sum
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RE: Minor changes to the Official Library Spec
#7
(2021-07-21, 11:59)Willy Tschager Wrote: Since there were no more comments for 3 months it should be added to the specs.

w.

I issued a call for votes:

https://forums.ldraw.org/thread-24745.html
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RE: Minor changes to the Official Library Spec
#8
Why do this text say:

Quote:shall be preceded by a 0 BFC NOCLIP statement and ended by a 0 BFC CLIP statement


when the bfc page say:
https://www.ldraw.org/article/415


Quote:affects all lines following the CLIP/NOCLIP option, either until the end of the current file or another CLIP/NOCLIP option is encountered.


Why should the sticker be forced to be ended by a 0 BFC CLIP, when the other rule say end of file ?
Is it correct to end a file without a 0 BFC CLIP statement, if you have used a 0 BFC NOCLIP?
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RE: Minor changes to the Official Library Spec
#9
(2021-07-21, 21:45)Magnus Forsberg Wrote: Why should the sticker be forced to be ended by a 0 BFC CLIP, when the other rule say end of file ?
Is it correct to end a file without a 0 BFC CLIP statement, if you have used a 0 BFC NOCLIP?

If the pattern geometry is at the end of the file, then the 0 BFC CLIP is indeed not needed. It is however required if any non-pattern geometry follows the pattern geometry. So the wording should be updated to reflect that.
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RE: Minor changes to the Official Library Spec
#10
(2021-07-21, 21:59)Travis Cobbs Wrote: If the pattern geometry is at the end of the file, then the 0 BFC CLIP is indeed not needed. It is however required if any non-pattern geometry follows the pattern geometry. So the wording should be updated to reflect that.

Agreed. Could you please update the wording and also rework the requirement of a set number in the KEYWORDS for both stickers and sticker shortcuts?

w.
LEGO ergo sum
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RE: Minor changes to the Official Library Spec
#12
(2021-07-24, 3:42)Willy Tschager Wrote: Agreed. Could you please update the wording and also rework the requirement of a set number in the KEYWORDS for both stickers and sticker shortcuts?

w.

OK:

Clarification to Sticker Geometry:
Quote:For stickers printed on a transparent medium, the type 1, 3, and 4 lines that comprise the pattern shall be preceded by a 0 BFC NOCLIP statement. If there is non-pattern geometry after the pattern geometry, the pattern geometry shall be ended by a 0 BFC CLIP statement.

The sticker should be oriented such that the top of the pattern aligns with the +Z axis. Exceptions to this rule may be made on a case by case basis.

New Sticker !KEYWORDS Entry section immediately following the Sticker Description section:
Quote:All stickers and sticker shortcuts should, at a minimum, include at least one !KEYWORDS entry in the form of Set <set number> where <set number> is the number of an official LEGO set in which that sticker appears. Only one set need be listed, but more may be if desired.

To reiterate what I said elsewhere, I don't have a strong opinion about this. I did the call for votes because it seemed fine, and there appeared to be consensus before I did it. I don't really plan to argue the merits of the above changes, but I would greatly appreciate it if anyone has problems with them, that they speak up before another call for votes happens.
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RE: Minor changes to the Official Library Spec
#13
Look good to me.

w.
LEGO ergo sum
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RE: Minor changes to the Official Library Spec
#17
(2021-07-25, 0:56)Travis Cobbs Wrote: OK:

Clarification to Sticker Geometry:

New Sticker !KEYWORDS Entry section immediately following the Sticker Description section:

To reiterate what I said elsewhere, I don't have a strong opinion about this. I did the call for votes because it seemed fine, and there appeared to be consensus before I did it. I don't really plan to argue the merits of the above changes, but I would greatly appreciate it if anyone has problems with them, that they speak up before another call for votes happens.

That's better now. Thanks.
Chris (LDraw Parts Library Admin)
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RE: Minor changes to the Official Library Spec
#11
Sorry for a greenhorn question: does this solve the issue when transparent part with sticker looks as with no sticker when viewed from the back?
   
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RE: Minor changes to the Official Library Spec
#14
(2021-07-24, 18:16)Milan Vančura Wrote: Sorry for a greenhorn question: does this solve the issue when transparent part with sticker looks as with no sticker when viewed from the back?

Read: https://forums.ldraw.org/thread-22204.html

w.
LEGO ergo sum
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RE: Minor changes to the Official Library Spec
#15
(2021-07-24, 18:16)Milan Vančura Wrote: Sorry for a greenhorn question: does this solve the issue when transparent part with sticker looks as with no sticker when viewed from the back?

I would answer yes, and no, to your question.

The idea is to make the pattern on a transparent sticker visible from the back side, but all the parts in your image are printed, not stickered.
Please note that LDCad use the word "with sticker" in partbins, containing both "printed parts" and "parts with stickers".

Have a look at parts 60581d50 and 60581dm2.
   

The sticker with a thermometer is made following the new suggestion. The print is visible, mirrored, from the back side.
The print on the Moria stickers are not made using a BFC NOCLIP and are not visible.
Should the Moria stickers be visible from behind? They are not intended to be placed on a transparent panel. The panel is grey in this set.


Printed pattern on a opaque part is not requred to use the NOCLIP.
Printed pattern on a transparent part should use the NOCLIP.

Should prints on a transparent sticker be forced to use the NOCLIP?

btw.
The 2 panels in your image with a porthole is not correctly made. These are prints on a transparent panel and should have been made using a BCF NOCLIP.


Attached Files Thumbnail(s)
   
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RE: Minor changes to the Official Library Spec
#16
(2021-07-26, 7:59)Magnus Forsberg Wrote: Have a look at parts 60581d50 and 60581dm2.

Please note that LDCad renders the whole part dual sided when a noclip is present anywhere in the part's .dat tree.

And even then, it could not show the pattern from the backside as LDCad does no triangle level alpha sorting (only part level).
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RE: Minor changes to the Official Library Spec
#18
Thank you for your answers, Willy and esp. Magnus. I've read the linked thread as well ("heavy" for me...) and Magnus' detailed answer here helped me to understand the topic more.

I know (and knew) about the difference between stickers and printed parts, although I do not know technical details. From my (user's) point of view, both types should work and both types should work regardless the "original part" LEGO released with either the print or sticker:

Stickers can be applied to any part of any color (of course)
In digital virtual world even printed parts may be used in any color, why not?

And, watching from the other side of the problem, it may be confusing even if you do not plan to use any printed or stickered part in new color: simply because you want to find the part with no print/sticker among all those parts - and watching "from behind" they look all the same. What is surprising and confusing, if the color is transparent. Look at the image I posted as an example.

BTW, I made a test: I added BFC NOCLIP to the definition of a print on this panel and it works in LDCAD both in the part bin and in the main model view:
   
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