Draco18s

You don't need to box here. withProperty(LEVEL, lvl) works just fine.

But vanilla doesn't do that, so it doesn't need the seed, so it doesn't synchronize it.

Because the client doesn't give a damn what the seed is. What would the client *do* with the information?

You basically just need to do it once (when the player joins the world) and store it. Every block can then query that stored seed. And yes, you need to do this, because how else would you get the data when the player connects to a server?

Vanilla doesn't know WTF capabilities are, they are a Forge thing. Use Choonster's test mod instead: https://github.com/Choonster-Minecraft-Mods/TestMod3/blob/1.12.1/src/main/java/choonster/testmod3/inventory/container/ContainerModChest.java

It really isn't that hard. If you're already supplying a capability, stop implementing IInventory and use SlotItemHandler instead of Slot in your gui.

What is deathZone?

You should inform Mojang.

This is what clever programmers are for. if(pos.x == N && pos.z == M && pos.y == 39) { log.message("hey! listen!"); }

That is not the proper variant syntax. http://mcforge.readthedocs.io/en/latest/blockstates/forgeBlockstates/

Add a logging statement to tell you what the output of that method is.

That's pretty much your only option, yes.

You won't be able to do this without rewriting a majority of Minecraft's internals.

Or generate them once and then remove the generation code...

Show your entire, updated, block class.

As far as I am concerned, any block variant that might exist gets an item, for the purposes of creative inventories and silk touch. The standard drop might be different and that's fine, but the variant should probably still have an Item version of itself. Again, whatever item that is supposed to be, you need to register a model for it. I can't tell you much more because your post is confusing as all get out.

Only way to implement this properly is to make two versions of your mod. Do remember that you can't ask for money with regards to features. It would violate the Minecraft EULA.

1) Use JSON recipes. 2) If you want metadata, you need to specify it with an ItemStack, like you did with charcoal 3) Use JSON recipes.

If you are in a chunk, you can be absolutely sure that the chunk +X and +Z exist. You cannot be sure that -X or -Z exist.

You need to register the item model for all of your block variants. I do it like this: https://github.com/Draco18s/ReasonableRealism/blob/master/src/main/java/com/draco18s/hardlib/client/ClientEasyRegistry.java#L45-L54

You're going to have to figure out the combined rotation yourself. You may want to convert to Matrix4x4 and do matrix math, then convert back.

Post the entire log, the actual error is almost always not the first one. There might be a second instance of the error with a different "Caused by:..." line. " MissingVariantException" is pretty much always triggered.

It will. If you'd made those changes you would have seen.

1) Why is your "register renderers" called from common code? That shit's client only. 2) Models need to be registered in the ModelRegistryEvent

"Not visible" means that it's private. You need to use Reflection.