I am having a problem to do with litematica not rendering schematic fake blocks that are colliding with real water, i tried the solutions in #64 but none of them worked

#64 had a reference to #21 - and that is still open.

#64 had a reference to #21 - and that is still open.

buddy that has been open since 2019, im trying to find out how to stop water from stopping the rendering without having to drain the ocean, doesnt even work with a mod that stops rendering water

Did you enable both ignoreExistingFluids and renderCollidingSchematicBlocks?

For me it still works fine in the 0.19.0 version for 1.21:

However it does look like it doesn't render through the surface of the water if you have the renderBlocksAsTranslucent option enabled. You do see the blocks if you go below the surface. But I guess as a workaround don't use the translucent option when working with under water schematics. Also the vanilla Fabulous graphics option causes some extra weirdness, and I'd recommend using Fancy instead, in general (until maybe the renderer rewrites fix some stuff at some point...).