I am using ROS Kinetic, and I'm trying to run waffle-pi simulation with open manipualtor. But in turtlebot3_manipulation_gazebo / launch directory, the world can load is only empty_world. How can I load rooms_world instead to test pick and place applications? Sorry for my bad english.
You can create your own launch file to replace the empty_world.launch in the turtlebot3_manipulation_gazebo.launch.
Please refer to below Gazebo manual for creating a world and a launch file.