FOSS gamedev and creative worlds

I wonder if it is possible to let register_decoration place a schematic with a negative Y.

Background: i would like to give roots to specific and huge trees. I noticed that default trees have something rootlike but i was somewhat unable to reproduce this with my schematic files... maybe because they're way bigger. :S

PS: I really hope ths is not the wrong categorie. :o

Update:

Paramat told me a way.

The current code looks like this:



So i created a new mts file with a height around of 62 blocks.
It basicly works but has an odd sideeffect:

How did you create the schematic? By saving a volume with Worldedit?
To create trees use the saveschems mod https://github.com/minetest-mods/saveschems and use Lua tables.
You'll need to use {name = "air", prob = 0} for all underground nodes that are not roots, otherwise you end up force-placing nodes.

What's the Y of the top and base of that floating stuff?
My guess is this is because you have a very tall schematic and you are placing it so that it passes beyond the border of the core voxelmanip.
If you use {name = "air", prob = 0} those nodes will never be placed so this floaty stuff will hopefully not appear.

Your roots must be <= 16 nodes tall to not pass beyond the base of the core voxelmanip.

How did you create the schematic? By saving a volume with Worldedit?

Yes, i created a .mts file using Worldedit.

To create trees use the saveschems mod https://github.com/minetest-mods/saveschems and use Lua tables.

Whoa, doesn't look simple but i'll give it a try. :o

What's the Y of the top and base of that floating stuff?

The top is 143, the base is inconsistent but seems to be +81 above the ground.

Your roots must be <= 16 nodes tall to not pass beyond the base of the core voxelmanip.

Ouh ... the tree is meant to hit the ground at 31 nodes. This means due the lacking of better options i need to make the whole thing 62 nodes height. :S

y = 143 = 127 + 16. This is the top of the core voxelmanip at mapchunk top + 16 nodes.

Your schematics placed at y = 48 to y = 64 have 16 nodes of roots below, then up to 16 nodes of schematic below which is passing beyond the base of the core voxelmanip (at mapchunk base - 16 nodes) and therefore (due to an unintended behaviour) appear at the top of the core voxelmanip.

You'll find that floaty stuff is above a tree below placed between y = 48 and y = 64.

So you will be fine as long as your schematic has, from top to base, 32 nodes of tree, then 16 nodes of root, then 16 nodes of "air" prob = 0.
The Lua tables are separated into vertical slices of trees, you can see the tree structure in the tables upside down.

Okey, the trees are now reworked with the saveschems mod.
Everything feels just fine, wonderful. <3

Thank you very much!
And thanks to iska, who helped me since this huge thing was a big time killer. :D