Sticker shortcut coloring

[Orion Pobursky]

I'd like to ressurect this discussion:
https://forums.ldraw.org/thread-28281-post-54224.html

To recap, the current practice is as follows:
- The part and the sticker should be color 16
- If the part is an assembly of a color 16 part and a transparent part and the sticker is placed on the transparent area:
  - For a solid color sticker, the color will be the color of the sticker back (usually white)
  - For a transparent sticker, the color will be Trans_Sticker

I'm advocating that all stickers in a sticker shortcut should be hard coded the color that they actually are.

In fact, I'm also leaning towards the notion that all sticker colors should be hard coded in the sticker itself (i.e. no color 16 boxes but white, clear, sliver, etc.). This would clear up a lot of problems but not sure we need to go that far.

[Rene Rechthaler]

I would extend it only slightly:

- If the part is an assembly of a color 16 part and a transparent part and the sticker is placed on the transparent area:

to

- If the part is fully or partially transparent (assembly of a color 16 part and a transparent part):

[Magnus Forsberg]

I'm advocating that all stickers in a sticker shortcut should be hard coded the color that they actually are.

In fact, I'm also leaning towards the notion that all sticker colors should be hard coded in the sticker itself (i.e. no color 16 boxes but white, clear, sliver, etc.). This would clear up a lot of problems but not sure we need to go that far.

This would be very sad to see. I don't like this.
I think most users, me included, don't want to see the border around the stickers. The stickers is a way to add a pattern to a brick and they should as much as possible blend in and disappear. 

The practice, as described above, is the most userfriendly and adaptable, and should stay as is.

[Orion Pobursky]

I think most users, me included, don't want to see the border around the stickers.

Now your speaking my language. This is a strong argument for maintaining the status quo.

That being said, is the white border more noticeable on LDraw models than on real life parts?

[Chris Böhnke]

Now your speaking my language. This is a strong argument for maintaining the status quo.

That being said, is the white border more noticeable on LDraw models than on real life parts?

Comparison:
Real Part:
   
LDView:
   
POVRay Render:
   

For older parts it's somewhat similar, but I'm afraid newer ones have a much less noticable border.

[Cam's Bricks]

The sticker material is also physically thinner on newer stickers thus less noticeable. Are we going that far into the weeds as well with this standard?

[Orion Pobursky]

Are we going that far into the weeds as well with this standard?

Not necessarily. I'm trying to strike a balance between unambiguous rules for parts authors and user experience.

I think the argument for maintaining the status quo has been made successfully.

Therefore the rule will be:
- All stickers in a sticker shortcut will be color 16 unless the sticker is applied (in whole or in part) to a surface on the base part that is hard coded a transparent color. If the previous exception is met, the sticker will be colored the actual sticker base color (e.g. white, silver, trans_sticker, etc.).

[Rene Rechthaler]

Not necessarily. I'm trying to strike a balance between unambiguous rules for parts authors and user experience.

I think the argument for maintaining the status quo has been made successfully.

Therefore the rule will be:
- All stickers in a sticker shortcut will be color 16 unless the sticker is applied (in whole or in part) to a surface on the base part that is hard coded a transparent color. If the previous exception is met, the sticker will be colored the actual sticker base color (e.g. white, silver, trans_sticker, etc.).

should it be

- All stickers in a sticker shortcut will be color 16 unless the sticker is applied (in whole or in part) to a surface on the base part that is availiable in a transparent color. If the previous exception is met, the sticker will be colored the actual sticker base color (e.g. white, silver, trans_sticker, etc.).

to include transparent (non-clear) parts like windows and windshields?

[Orion Pobursky]

should it be

- All stickers in a sticker shortcut will be color 16 unless the sticker is applied (in whole or in part) to a surface on the base part that is availiable in a transparent color. If the previous exception is met, the sticker will be colored the actual sticker base color (e.g. white, silver, trans_sticker, etc.).

to include transparent (non-clear) parts like windows and windshields?

No.

There are 3 scenarios:
- Geometry under the sticker is entirely color 16: No problem, sticker substrate will be invisible.
- Some/All of the geometry under the sticker is hard coded a non-transparent color: No problem, sticker substrate will be (mostly) invisible.
- Some/All of the geometry under the sticker is hard coded a transparent color: Problem, sticker substrate will be visible through the transparent section so needs to be hard coded it's actual color.

[Rene Rechthaler]

No.

There are 3 scenarios:
- Geometry under the sticker is entirely color 16: No problem, sticker substrate will be invisible.
- Some/All of the geometry under the sticker is hard coded a non-transparent color: No problem, sticker substrate will be (mostly) invisible.
- Some/All of the geometry under the sticker is hard coded a transparent color: Problem, sticker substrate will be visible through the transparent section so needs to be hard coded it's actual color.

but the 4th case isnt rare:
- part is color 16 but will be colored (non-clear) transparent when used due to being only availiable transparent...
(are there other sticker base colors than clear foil and white paper?)

[Orion Pobursky]

but the 4th case isnt rare:
- part is color 16 but will be colored (non-clear) transparent when used due to being only availiable transparent...
(are there other sticker base colors than clear foil and white paper?)

Why is this case different from case 1?

[Rene Rechthaler]

Why is this case different from case 1?

because if a paper sticker is on a transparent part, it will be nearly invisible from behind (paper stickers dont need NOCLIP)
and if a transparent sticker (surface also col16) is on a non-clear transparent part, it overly darkens the visibility due to the additional refractional surfaces...
this is visible especially in all stickered parts which are normally trans-brown or trans-dkblue.

[Orion Pobursky]

I don't like this for 2 reason:
- I see this as a renderer problem.
- The library generally doesn't care what color a part comes in. Color 16 can be any color. Having some stickers hard coded and some not subverts consistency and user expectations.