Can an actor be kicked from one part of a room to another without being Chuck Norris and without really causing serious injury to the “victim”? Of course, just mix the GIMP photo editing with the Kdenlive editor, and you’re done.
In movies it is quite easy to make fighting scenes. At least from the editing point of view: it is complicated for the actors, who normally have to learn a real choreography, so that they can repeat the same movements every time the camera takes them from a different angle. For the rest, no special effects are needed: when an actor is hit, he falls, and just film his movement. This applies in “normal” conditions. What if, on the other hand, we want the actor hit rather than falling to be blown across the room? It is a typical effect of karate films, in which you want to demonstrate the attacker’s strength. What happens, normally, is that one of the two actors hits the other: this flies (i.e. it is suspended from the ground) up to the wall placed in the direction of the shot, while the camera follows its movement. The first step is done: we have analyzed the effect we want to achieve. It is therefore immediately evident that the problem lies in being able to fly the actor who suffers the blow. But there is a detail: just because the punch (or the kick) was very violent, the flight movement lasts less than a second: twenty frames at most. Then we can simplify everything using photographs: ten or twenty in sequence are enough and the effect is built. In particular, what we can do is to fix the camera (or camera) on a tripod. You choose the first shot and film where one of the actors hits the other. At this point the recording stops, the camera is moved slightly in the direction in which the victim will have to fly, a high enough stool is positioned in the scene and a photo is taken with the actor-victim on the stool pretending to have been hit. Then you remove the stool from the scene and take another image without moving the camera. In this way we obtained two images with the identical background: the only difference is that in one there is the actor sitting on the stool. Now we can move the camera again in the same direction, place the actor again on the stool but this time a little closer to the wall on which he will have to crash, and take two more images (always one with the actor and one only with the background). Eventually we will get a sequence of images which, seen one after the other, give the illusion of the actor’s movement. We also took photographs to the background because in this way we will be able to superimpose the pairs of photos created in order to cancel the stool, making visible what is behind it. In this way the actor will seem suspended in the air. To complete the effect, just hold the camera fixed in the position of the last photo taken, and film the actor who performs a jump backwards so as to slam his back against the wall and fall to the ground. By combining the first movie, the sequence of images, and the last movie, we will obtain a perfect rapid flight. You can find the example video at the following address: http://www.youtube.com/watch?v=jcawWs_oAzQ
Shooting angles, wide angle, and cuts
There is no “right” way to shoot the fist sequence: we propose that you start with a shot of the actors from the side, and then simply rotate the camera in the direction of the actor-victim’s flight. This movement, combined with a wide angle lens, will provide a good image distortion effect, which will improve the rendering of the effect. Another very important question is that of the cuts: in an action film in general, and in the fighting scenes in particular, it is very important that the times are always very fast. In practice, the actions must follow one another without interruption, otherwise the tension drops and the effect does not perform well. So, in doubt, it is better to cut the videos a little more, stopping a few handfuls of frames earlier, rather than risk having a too slow passage from the punch sequence to the flight sequence, and from the flight sequence to the fall one. along the wall.
Two shots for one frame
We prepare the pair of photographs for their merger


Let’s build the frame
It’s time to take the photograph that has never been taken




From photos to videos in a couple of clicks
Kdenlive allows us to build a clip with the images made




Every clip in the right place
To obtain a good effect, pay attention to the assembly



