Schematica is an open-source (CC BY-NC-SA 3.0) modification for Minecraft.
The project requires a parent MinecraftForge project to successfuly compile.
To build a jar file, that can be installed alongside MinecraftForge, you'll have to create the file build.properties with the following properties (the default values may be changed to your liking):
dir.project=${basedir}
dir.workspace=${dir.project}/..
dir.mcp=${dir.workspace}/mcp
dir.release=${dir.project}/release