BuildCraft

BuildCraft is a mod for Minecraft. BuildCraft itself is licensed under the MMPLv1 or MPLv2 if you need the specifics, but generally, you can. By default, many simple (primarily worldgen/decorative) blocks are supported out of the box, such as the kind of blocks added by Chisel 2 or Ztones. However, for many other mods, special support is required to allow for rotation and remove the chance of duplication bugs appearing. BuildCraft Compat is a BuildCraft addon designed to add cross-mod compatibility with other mods. BuildCraft is in the process of moving back to the MJ power system. However, due to BuildCraft being in alpha no other mods support it (or should support it, as its still making breaking changes to the API.