Okay, good to know it got figured out. Bit strange that optifine can't handle it. Here's a totally transparent version of the default glass, though, drop that in your resourcepack and overwrite the old, and see if that fixes the problem so you can use both.
Oh man, above and beyond! Renammed it, dropped it in, worked perfectly. What's odd is the model in your hand was always ok even before this fix, it's simply when placed as a block in the world that it became opaque. But it's all perfect now, glass is now glass! Even regular glass panes are fixed too. Thank you so much for this.
There's a couple issues. I don't have the photoshop brush I used to originally draw the "pencil" lines, so I have to use one that looks a tiny bit off and it bothers me. The shading and texture on the paper makes it hard to add icons, because those are off to the side and I have to guess on what to use as their background. I've got an idea for one that'll be a lot easier to work with, and it'll be easy to customize for each variant as well.
The Meaning of Life, the Universe, and Everything.
Brazil, land of Zuera
So 1.13's renaming of everthing seems to have messed things up again, Normal red sandstone (side only), dry farmland, nether wart (all 3 stages), second stage of potatoes (all other plants are fine...), front side furnace (off only), anvil sides (tops are fine), mushroom block stem (the white shared part), dispenser front (on only), rails (all normals) are missing texture... prolly filenames are wrong. Also, now there are dead corals (normal ones)
Techinicallities aside, let's go over good stuff;
Again, i can finally see use in stripped logs with your ornated textures, the bleeding oak is specially good. Turtle helmet is fashinable (It also looks really good with the elytra i put it in the same stand on). The Trytend looks damn good.
The new iron horse, it has fiery spots. This is good. And the skeleton horse looks aweome too.