Some custom item models appear dark in the inventory

Can confirm this happening with "Default 3D" Texture Pack, which turns lot of 2D Item Models into 3D Models.

With today's Pre-Release this issue was 10% fixed, since MC-166716 only was focused around Shields & Tridents, these 2 are 3D Items in vanilla so that's why it got more exposure but the issue still present for people that use 3D Models.

✔ Before

❌ After

I think this has to do with rotation. When a custom modeled item isn't rotated at all in its GUI display setting than the shadow rendering bugs out and causes it to go dark. (I am also having this issue)

Yes, it has to do with how the new Rendering Engine applies shading to anything displayed on the GUI, I strongly believe that this issue is related with the fix of MC-162518, ever since it was fixed on Pre-Release 3 this problem started.

So anything rotated like a Block will automatically get this opaque shading that is only supposed to be present in Blocks.

This 100% has to do with the model's gui rotation value. I have yet to determine specific values it happens at, but any model I have set to "rotation": [30, 45, 0], [30, 225, 0], or anything else close to a default block's rotational value, no longer looks dark in the gui. This becomes rather frustrating however, as having a model always displayed at or near the same gui rotational value as a block is very much not ideal as many custom models, especially tools, are much better displayed at a more "flat" angle as opposed to an isometric angle.

Hopefully this can get a fix soon as it ruins the look of many cool things in custom resource packs.

Yeah I have this issue on my server too. Because of this I can't use my resourcepack on my server so I won't update my server to 1.15 untill this is fixed!

Thank you for the reply- I did not understand that I was meant to have parented all of my models to something specific builtin.

I did end up making a common parent, but that still involves touching all the models so it didn't really help except to maybe future-proof a little. I just wrote a script, so it didn't take me all day 🙂

All texture-only models already use `builtin/generated`, since it's only way to generate model based on texture. I don't know the contents of you resourcepack, but you shouldn't need to make that many changes, since it's only required for making 3D models that still want to keep their legacy flat look in GUI (like ladders or rails).

I had some flat but many 3D, but they all looked dark. It's certainly more noticeable on the 2D ones (I have many that represent icons). Particularly because I already have "dim" versions of all the icons to use when they are disabled.

But the actual 3D models (wands, bows, swords, etc) also looked dark. I don't have any texture-only models, so I guess I never had need to use builtin/generated?

Most of my models did not have a parent, now they share a common parent that currently just has "gui_light: front" on it, but at least now it'll be easier for me to add more common properties if I need to.

In case it's helpful to anyone, you'd probably need to tweak it a bit for your own purposes but here is a script that will recurse through a directory structure and add a parent to any models that don't already have one.

How does that script work exactly?

You download the script and put it in the root "models" folder of your resource pack and run it with 

php addrpparent.php

It'll edit all your json models to add the "item/custom/lit" parent, if they don't have a parent set already. You can edit the script to use a different parent if you want. But you'll need to have that parent in your rp, if you want to use mine just copy this into item/custom/lit.json

{ 
"__comment": "This is here to fix lighting issues with GUI items in 1.15", "gui_light": "front" 
}

Make sure to back up your RP source first, in case something does wrong.