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I don't understand:

OBJ exporters may split blocks into separate objects, where each block type is split as its own object.

What exactly does this mean? Please give an example or two, and these would be nice to add to the docs. I think the answer is "true" for Mineways, but I can't tell. What's the purpose?

In an OBJ file you can do things like:

g Stone
usemtl stone
f 7021/15/2 7011/132/2 7254/117/2 7263/1/2
...

g Grass_Block
usemtl grass_block_top
f 6915/15/5 6920/132/5 6919/117/5 6916/1/5
...
usemtl grass_block_side
f 6914/15/1 6915/132/1 6916/117/1 6913/1/1
...
usemtl dirt
f 6914/1/2 6913/15/2 6918/132/2 6917/117/2
...

Is this then a split block? I think so. I'm guessing that the "g" group attribute in an OBJ file means "true".

There are lots of variants here.

One area where there seems to be a discrepancy between in-game and exported OBJs is with block states. Minecraft allows editing blocks state in-game for creativity purposes. Some examples include:

• Preventing blocks such as walls, fences, and glass panes from being chained
• Allowing blocks to float that normally wouldn't be allowed (take levers for instance)
• Etc.

Although CommonMCOBJ states as a non-goal

• Governing every behavior in Minecraft OBJ exporters; that would be hard to adopt and stifle experimentation,

I think an exception can be made here as it's a vanilla game feature with legitimate use, and expands creative opportunities for artists. Granted, it may cause exports to be slower, but ultimately, exports shouldn't look different from how they look in game.

As such, I propose we add the following section to CommonMCOBJ for V2 of the spec (2025):

Block States

OBJ exporters following the CommonMCOBJ spec shall export the proper block state for all blocks. If an option to only check a pre-determined list of blocks for states exists to speed up exports, it shall not be enabled by default.

EDIT 01/04/2024: if wanted, we could change the description of CommonMCOBJ to the following in V2:

CommonMCOBJ is a spec to allow exported Minecraft OBJs to be closer their in-game counterparts, by creating a common standard for OBJs and creating extra metadata for details that would otherwise be lost.

For record keeping sake, see the following conversations for aligning on the format. We can mark these as done once the scheme is agreed on each front and implemented, might be good to reference also which release in each contains the update when it comes to that point:

• jmc2obj: jmc2obj/j-mc-2-obj#243
• Mineways: erich666/Mineways#125