When I place my block, I can see the world below it, like it's translucent. I believe it's an easy fix, but I'm not too sure how to go about it.

Hi

Without a screenshot it's hard to know exactly but there are two common problems which cause this:

1) Not setting the renderlayer properly in your clientsetup

RenderTypeLookup.setRenderLayer(StartupCommon.blockPartial, RenderType.getSolid());

2) Not using a proper blockshape in your block

private static final VoxelShape BASE = Block.makeCuboidShape(BASE_MIN_CORNER.getX(), BASE_MIN_CORNER.getY(), BASE_MIN_CORNER.getZ(), BASE_MAX_CORNER.getX(), BASE_MAX_CORNER.getY(), BASE_MAX_CORNER.getZ());

@Override public VoxelShape getShape(BlockState state, IBlockReader worldIn, BlockPos pos, ISelectionContext context) { return BASE ; }

See here for an example (mbe02)

https://github.com/TheGreyGhost/MinecraftByExample

-TGG