Hello! New to the Minecraft dev scene so bear with me, but I'm pretty bewildered here. :)

I'm working on a side project to try and implement a layer-by-layer blueprint viewer (a la Schematic2Blueprint) that works on .schem Sponge format schematic files, and am using this library as a dependency. With some schematics (I'm using Amulet to export them to .schem, if that makes any difference) it works fine, but with others, weird stuff starts to happen in the block ordering.

Case in point - I set up a big pile of many different block types in my creative world so I could test how my app behaves on all of them:

The .schem file itself seems to be fine, because I can re-import it into Amulet or Litematica and all the blocks look correct. However, parsing it with SchematicUtil.load has some weird behavior.

The first level of blocks, for instance:

Going from north to south on one vertical Y value (if I understand correctly) should be

Schematic schematic = SchematicUtil.load(path);
int length = schematic.getLength();
int height = schematic.getHeight();
int width = schematic.getWidth();
for (int i = 0; i < height; i++) {
    for (int j = 0; j < length; j++) {
	    for (int k = 0; k < width; k++) {
		    SchematicBlock block = schematic.getBlock(k, i, j);
	    }
    }
}

which is what I am doing in my application. Given the row above, the result I would expect would be

minecraft:stone
minecraft:granite
minecraft:polished_granite
minecraft:diorite
minecraft:polished_diorite
minecraft:andesite
minecraft:polished_andesite
minecraft:deepslate
minecraft:cobbled_deepslate

Instead, what I get is

minecraft:stone
minecraft:granite
minecraft:polished_granite
minecraft:polished_blackstone_brick_stairs
minecraft:grass_block
minecraft:mossy_stone_bricks
minecraft:grass_block
minecraft:yellow_stained_glass
minecraft:grass_block

As you can see, it starts off correct and then kind of goes off the rails from there. The rest of the parsing gives much the same result - some blocks are listed as being where they are supposed to be, while others seem to have been swapped in from wildly different parts of the schematic, or just slotted in at random. (The grass_block is a repeated offender.)

Am I doing something wrong in how I'm using the library? Or is there a sneaky bug lurking around here? I've attached the .schem file in question here: palette-lvl1.zip; please let me know if there's other info that would be helpful! :)

(Thanks very much for this tool, also! Assuming I can figure out what the issue is here, it's been awesome in all other regards. :) )

VoxelSniper used to have a proprietary system for stencils (basically schematics) which no longer works (due to block id's no longer numerical for many a year). In our fork we have refactored this to use schematics using Schematic4J. Creating schematics from an area selection is something that we still have to implement.

We would like to see a way to create a schematic from an input of blocks, entities etc. Perhaps something like a builder pattern.

Is this something you would consider within the scope of Schematic4J?

Some schematics don't seem to load properly, while others work just fine. I tested a few schematics, and it seems like .schematics and .litematics don't work while .schems do work.

Examples

TestedSchematics.zip contains the schematics I have tested.

1 and 2 work fine. 1:

In 3 and 4, all blocks have suddenly become air. Screenshot of code (offset returns 0,0,0):

5 outputs a bugged schematic that somewhat looks like what it should look like, but obviously it is not 100% correct.

Hope you can do something with this.