I placed down my house some blocks from this mod and nothing go wrong. after restart i started to make a smeltery near. Now im unable to join , every time a try and i load my house the client crash. This is the error: The game crashed whilst tesselating block model The game crashed whilst tesselating block model Error: java.lang.NullPointerException: Tesselating block model Edit: Problem solved my self, the problem is the incompatibility of the mod with Optifine, just removed the mod. Sorry for useless thread.