Variable to actual compiling project folder

Hello, I want to enter to actual compiling project folder in .pio folder. For example: in .pio folder I have 3 environments: board1, board2, board3 and I would like to get path in platformio.ini file to actual compiling folder. When I compile code for board2, I want to get path to workspace/.pio/board2.

Example path: {/ folder that I want to enter}.
I need an equivalent of platformio.workspace variable, but whose returning a path to .pio/compiling folder

So… $BUILD_DIR?

No, but thanks to you I found variable that I needed: PROJECT_LIBDEPS_DIR.
Thank’s for help.