Earlier this summer the Digital Commons was approached about helping produce and create a video for an Alternate Reality Game (referred to as ARG) for the Penn State University Libraries open house. The video entailed among other things making a stuffed lion located in the library disappear, We had to do this on video with out being able to physically touch or move the lion. The initial problem that we faced with this shot was that in front of the lion sat a large glass window that had multiple reflections on it.

We immediately contacted our colleague Dave Stong for his excellent photoshop expertise, basically we needed to take still images of the lion on display and have them cut apart in photoshop so that we could put them back together in adobe after effects(more on the photoshop portion of this visual effect can later be found at Dave's blog ).

We decided early that we wanted to do more than just make the lion disappear, we wanted to challenge ourselves and have someone walking in front of the lion as it or after it disappears. To do this we shot some video of our student actress in front of a green screen reacting to the lion disappearing. The idea being that a real person will walk in front of this lion in it’s case before it disappears and that the whole thing will be moving via a glidecam shot. To achieve this we shot our actress on the green screen and used small bits of gaffer tape as tracking dots placed on the green-screen itself. It is important to use tracking dots anytime one's shooting green-screen with movement, that way the background can match that movement and the shot seems real. Once I got the footage back into Adobe After Effects(AE) I went ahead and motion tracked those tracking dots to get scale, and movement for our background plate.

The photoshop image of the Lion was broken up in to several layers including the background mural of the mountains, two middle ground layers of some rocks and the lion itself, a foreground layer of the leaves at the front of the display and two more layers of the display case and the reflections in the window. In 3d space anytime you move your point of view the foreground elements in the view will move at a differing rate than the middle or background elements depending on your perspective. I took all of the photoshop layers into AE and separated them in Z space, to help me achieve a 3d effect or sometimes called a 2.5d effect. Then I setup a camera in after effects to simulate a single point of view of the animation. At this point I needed to align all the images and resize them so that the original image is restructured in 3d space.

Now that the scene was built I took that motion tracking data that I gathered earlier from the green screen footage and applied it to the back-most layer of our background plate. Once done the back layer will move in conjunction with the green screen, I then parent the other layers to the back layer so they will move with it. Since I am using a camera as my point of view it will appear that the back most layer will move less drastically than the layer in front of it and so on. (This is and should be subtle since the space is not that great) This movement gives me a quasi 3d look or a 2.5d effect. Additionally now the background plate moves with the actual video footage and should look like the actress is walking in front of the real case.

At this point all that I need to do is build an effect to make the lion actually disappear, and since the video was about a magic trick we decided to embrace that and use some sort of smoke and light effect. The first thing I did was setup several AE lightening effects to run along the lion just prior to it disappearing to make it look like magical power was building up. I then went into Motion to grab one of their smoke presets, these generally don’t look very good, and exported that into AE with an alpha channel. I set the smoke to composite in screen mode so it didn’t look so bad, then layered this with a duplicate version of itself played in reverse so the smoke would appear then disappear working as a vortex dragging the lion out of our world. I then added a shine effect to make the lion sort of glow Penn State blue while it is disappearing. Lastly I did a quick resize of the lion at the end to make it appear as if it were being sucked into my smokey vortex and dropped the opacity of the lion layer to make it disappear.

The only thing left to do is to composite the actual video footage on top of the lion display case. This video footage is green screen so I went into my chroma key effects and grabbed keylight 1.2 and applied it to the green screen layer. Admittedly we had a few shadows on our green screen and keying out the green was extremely difficult in AE, after working on it I was able to get all of the green out but was left with the rigging(lights and motion tracking dots). To remove the rigging I setup a mask around our actress and animated it in portions as to not cut off the actresses head and still keep the rigging hidden. I was only able to remove about 85% of the rigging using this method so that left me no choice but to rotoscope(frame by frame) the rest with the AE erase tool. To give you an idea the whole shot is about 300 frames. I had to make a few minor adjustments resizing and reframing the video but all it all it turned out fairly well. To finish the composite I had to add some noise using an adjustment layer to the background plate so that it would match the video look of the composited video. Below you will find the finished video.

The Nittany Lion is Missing! from psulibs on Vimeo.