Following a Path in V-REP
Open a new scene in V-REP. Go to the top menu bar and select Add > Path > Segment type. A new object named "Path" with a little blue snake icon should appear in the scene hierarchy. And in the 3D viewport you should see a short straight line. This is our beautiful new path. It represents a motion path through space. Each point along its length has a position and an orientation. We can use paths to direct the motion of objects in V-REP, like the target for the inverse kinematics moving a robot arm.
Select Add > Dummy to add a new Dummy object to the scene. Dummy objects have a position and an orientation but no geometry. Let's try to get our new Dummy to move along our path when the simulation runs.
Try hitting the play button now. Nothing should happen. Hit stop. Without us telling V-REP to move the Dummy along the path, nothing is going to happen. Right click the Dummy in the scene hierarchy and select Add > Associated child script > Threaded. Next to the Dummy in the scene hierarchy there should now be two new icons, a page and three bars. The page represents the script we just added and the bars are the optional parameters for the script. We will use the script to tell V-REP to move the Dummy along the path.
Double click the page. A new window should appear with some colored text in it. This text is the content of the script we just created and added to the Dummy. Right now it doesn't do anything, but we are going to change that by replacing all of the text with the following new script:
Now close the script window and hit play. Your Dummy should move along the path from one end to the other. Try repeating the same task but with the UR5_target Dummy in a scene with the robot!