Summary

Falling Sand is a simple mod that rewrites the logic for falling blocks. Most falling blocks such as sand and gravel will no longer be converted into entities when suspended in the air, they will instead stay as blocks and move down, and can now slide down hills and cliffs, adding landslides and sometimes even cave-ins! This can also improve performance with falling blocks in some cases, as blocks cause much less lag than falling block entities. The mod can also be configured to apply these physics to any blocks you want!

Config

Config can be found in your mod profile/config/falling_sand.json

Config for 1.2.x

"applyToAllBasicFallingBlocks"
Defualt value: true
Makes most falling blocks without much custom behaviour (such as sand, gravel and concrete powder) be affected by the mod's physics.

"additionalAffectedBlocks"
Default value: [
    {
      "blockName": "minecraft:sand",
      "slideChance": 0.85
    },
    {
      "blockName": "minecraft:red_sand",
      "slideChance": 0.85
    },
    {
      "blockName": "minecraft:gravel",
      "slideChance": 0.5
    }
  ]
Additional blocks to be affected by the mod's physics.
Example value, will make andesite, granite and diorite be affected by the mod's physics, each with a 20% chance to slide diagonally: 
[
    {
      "blockName": "minecraft:andesite",
      "slideChance": 0.2
    },
    {
      "blockName": "minecraft:granite",
      "slideChance": 0.2
    },
    {
      "blockName": "minecraft:diorite",
      "slideChance": 0.2
    }
  ]

"sandFallDelay"
Default value: 4
How much time in ticks passes between physics steps (1 second = 20 ticks).

"defaultSlideChance"
Default value: 0.75
How likely it is for a falling block that is not in additionalAffectedBlocks to slide diagonally.

Config for older versions

"applyToAllBasicFallingBlocks"
Defualt value: true
Makes most falling blocks without much custom behaviour (such as sand, gravel and concrete powder) be affected by the mod's physics.

"additionalAffectedBlocks"
Default value: []
Additional blocks to be affected by the mod's physics.
Example value, will make andesite, granite and diorite be affected by the mod's physics: 
[
  "minecraft:andesite",
  "minecraft:granite",
  "minecraft:diorite"
]

"sandFallDelay"
Default value: 2
How much time in ticks passes between physics steps (1 second = 20 ticks)