In the framework of our compositing course and development of critical thinking around the creation of special effects, we developed an exercise which requires students to make three characters interact with each other. The challenge being that the three characters must be played by the same actor so the ‘interactions’ are completely staged.



Students needed to do everything, filming and special effects. This is certainly difficult, but nothing is insurmountable with the help of DSLRs and the Nuke compositing software.
This is a very technical exercise, but one which, of course, encourages the students to go beyond the techniques.
In this exercise, we are covering all the creation steps of a special effects enhanced video.
The duration can be between 10 to 20 seconds (250 to 500 frames in the Frenglish jargon often used in this field).


Pre-production: anticipating as much as possible

During the pre-production phase, we need to think about the different ways to proceed in order to guarantee that the interactions will work (rush, the passage of objects, etc.), but also to be as prepared as possible for the filming process and the treatment of the images during post-production.


First comes the writing of the “mini-script,” it must detail the exact gestures of the characters, determine whether the setting(s) with help or hurt us, what lighting requirements are needed and which interactions might be problematic.


Filming: ensuring synchronization

Once the pre-production is finished, filming begins. Preparation for this is brief, but very carefully organized.
The actor should look towards his or her (invisible) clone and seamlessly pass objects to actors working as doubles.
One must also ensure that the background doesn’t change at all and that the exact lighting and shadows are maintained from one take to the next.


Exercice Clones - Compositing - ArtFxIt is difficult to perfectly synchronize the actors during the different takes.
We have found solutions like making recordings during the sound takes or using the audio indications from our cell phones. Therefore, the actor in each of his or her different roles can know when to do each of his or her movements.
There are markers put in the scene to indicate where the clones are looking, helping the actor make ‘eye contact’ and
reinforcing the realism behind his or her movements.


Post-production: integration in Nuke

Then comes the post-production stage. One must first synchronise the three takes into one to make the actions correspond.
Then comes the moment of integration using Nuke software, armed with “courbes de Bézier”, a fundamental rotoscope tool. This technique is the basis of compositing. It consists of outlining characters in order to then paste them into a different shot, isolating elements within a video, deleting other elements, etc. It is generally the most time consuming stage, since you often have to do this frame by frame.


Exercice Clones - Compositing - ArtFx

Nuke's Workspace


All the special effects stages

This exercise, based around rotoscope techniques, allows us to experience the different steps involved in making a special effects enhanced video. We have to be able to capture footage, primordial phase in the special effects world, and what’s more, we have to work on the preparation needed for filming. This preparation is also essential in order to have successful filming and post-production experiences. An actor who is not looking in the right direction, lighting which changes from one take to the other or objects which are moving between takes….all of this can create many long hours of work to compensate for a lack of preparation or filming errors.


In summary, this is a very informative exercise!


The “Clones” exercise results

Exercice 3ème année VFX “Clones” from ArtFx on Vimeo.


Other photos from work done in Nuke

Click here to view the slideshow.

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[small_button]English version by Danielle Harrell, English teacher for ArtFx[/small_button]