Minecraft version
1.17.1

Mod version and malilib version
Litematica : 0.0.0-dev.20210906.183617
MaLiLib : 0.10.0-dev.26

Description of the bug
Hello,
Sorry in advance for my bad English and if this is a duplicate post.
Concerning my problem, when adding a schematic overlaying another schematic, the first one makes the part corresponding to the new one disappear. Working by "Asset" to establish the final project, it makes the work a little more complicated because I have to make the schematic visible or not depending on where I build.
This case never happened in the previous versions of Minecraft (1.16, 1.15)
Thanks for this mod, it's great !
Sakriel

Screenshots
For this example, the first schematic is the bridge on the right and I added the tower in second (left)**

For this example, here I have disabled the tower schematic (second in placement)

For the most part thus far it has never been "officially defined" what would/should happen if you overlap placements. I think maybe it didn't override blocks with air before then? Currently it probably depends on the order of the placements in the loaded placements list, so what comes later will override what was there before. The override behavior may have changed when I did some schematic placing to world related code changes recently. For the long term maybe I should provide a replace option for the schematic world/rendering for this behavior, the same way the Paste mode has the pasteReplaceBehavior option.

But also in general the recommended way to use the mod is to not overlap placements, if possible. That will also cause other issues, like the material lists being off, if you use the placement-based material list, which counts the blocks from the schematic world, and the overlapping sections of the placements would thus get counted twice and mixed up between placements, depending on the order and what overrides what.

I know it's sometimes not practical to avoid all overlaps, an thus I think I'll add that new option. But for example in this example case, although it's a bit difficult to see in the screenshots what belongs to the edge of the tower schematic for example, I would recommend capturing all schematics very tightly with no extra space outside of the builds, so that it would be easier to not overlap them later on. And also use multiple sub-regions when applicable to more tightly capture builds that have wildly different thickness sections and such. Then you can also just turn on or off some of those sub-regions from the placement, if needed.

Thanks a lot for this quick answer.
For the screenshots, indeed we see less well the two zones that overlap ^^' I rarely use the lists of materials for the construction with the assets for this part since I assemble several schematics to create a district (see screenshot below), but I understand completely the problem that it generates afterwards. After that it's my way of working with Litematica, I can try other approaches.

I did with regions and sub-regions for another part of the project, very usefull if everything is already built in creative. For the example I have my schematics divided by pieces (house body, roofs, various decoration, ...) then I assemble on my server in survival by overlaying and I build accordingly.

For the old versions, during the superposition between the different schematics, the list of the materials indicated of the surplus (what is normal) and for the visual, it took the block of the second schematic (that after the first). If it can help for this improvement ^^

• Red : House Body x2
• Blue : Roofs x2
• Green : extension decoration (a terrace in this case)
• Yellow : Decoration, a tree