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Recent YouTube wanderings led me to some videos about 2001, the making of the Star Gate sequence, and so on, which got me thinking… 2001 is among my all-time favorite movies. It is film qua film, not merely a novel thrown up on the screen. I saw 2001 at the Cinerama Theater in LA in 1968, with my college comrade and long-time friend, the late Robert Blalack, who received the VFX Oscar for Star Wars (1977). To say that we were mind-blown would be the understatement of understatements. These days, movie editing programs and software packages usually have some form of the slit-scan effect in their bags of tricks. But why use them when I might be able to re-create a virtual version of the Douglas Trumbull set-up in A:M? Down the rabbit hole I went with internet research on 2001, Trumbull, and slit-scan techniques. Trumbull set-up (details vary depending on source): Camera with open shutter on 15’ track. Slit-scan structure to support 4’ tall slit (I have not found width of slit documented anywhere) and Artwork moving behind slit; slit is just off-center (Trumbull has said there were 2 slits, one for the left pass, one for the right pass). Artwork greater than 4’ tall and as wide as you want to make it — many feet. Camera moves down track from 15’ away to 2” (or so) toward Slit/Artwork over a period of 1 minute while Artwork is moved approx. 8” horizontally; Trumbull mentions that the camera was panned slightly during this move. The result is one frame of exposed film, either the left half or right half of frame, depending. Rinse and repeat. First proof of concept in A:M: I made a simple model, a panel with a slit in it, to scale, and an artwork panel set just behind the slit. In the Cho, I placed the Camera 15’ away from the Slit-screen/Artwork model. I keyframed the camera to move toward the model while moving the artwork behind the slit. After rendering a series of frames, I composited the frames into a single frame and could see that I was getting something like the desired image stretch/smear of the slit-scan technique. So the approach sort of worked, but the method was tedious. How to “hold the shutter open” for a single frame during the camera move? Then I remembered the MUFOOF (Multiple Frames in Only One Frame) technique posted by Xtaz in 2005. As the Camera cannot be moved toward the Artwork within the MUFOOF action, I realized I would need to move the Slit-screen/Artwork model toward the Camera. I made an action to do that, did test renders, and got strange results. So I made an action that ran the set-up backward, moving the Slit-screen/Artwork model from 2” in front of the Camera to 15’ away, and got good, predictable results. Also, the Artwork cannot be moved within the MUFOOF action and have its new location available for the next frame. A second action is needed to move the Artwork between frames. I did many test renders of the backward MUFOOF Slit-screen/Artwork model move with Artwork moves between MUFOOF frames, while tweaking the Multi-Pass and Motion Blur values, and got some beautiful results. An example, using a 2 slit model: The light trails move, scintillate, but the dynamic acceleration characteristic of the Star Gate sequence was missing. The final ah-ha moment was realizing I could move the Slit-Screen model element across the Artwork as the model travels away from the Camera. That worked. Here is a wireframe of the set-up: Once I had a working slit-scan system, I wanted to see what actual 2001 artwork would produce. That artwork is long gone. But a couple of clever people have managed to deconstruct/reconstruct it through some coding wizardry. My 2001 Artwork was extracted from YouTube video https://www.youtube.com/watch?v=meEhkceeA94 and website https://www.seriss.com/people/erco/2001/ which reconstructed the original graphics by taking strips from each frame and placing them side by side. An example still from a render using the reconstructed artwork, left side of frame only: As my set-up has the slit on the left side of the model and the artwork moves from left to right and the Slit-screen/Artwork model moves away from the Camera, the rendered sequence moves away from the viewer unlike the actual Star Gate sequence. No matter. Modern movie editing software supports flipping sequences horizontally, vertically, and end-for-end. Here is the link to a short version of the Star Gate sequence as done in A:M, rendered at 720p and up-res’ed to 1080p, including a Ligeti-esque soundtrack: https://youtu.be/P4kflu1okxE Two issues with Multi-Pass that do not exist with real film emulsion: Brightness of image diminishes from outside edges inward as passes progress; I used high intensity values (2000 - 4000%) for the Keylight to compensate which causes a somewhat blown-out result; kind of OK because the overall effect in 2001 is blown-out. Banding from over-lapping passes; no complete remedy that I know of. Think of it as a feature, not a bug. High contrast artwork mitigates the issue somewhat. Here are the files: slit-scan-backward-indy-2001-artwork-60sec-01.chosingle-slit-screen-2001artwork-system01.mdldouble-slit-screen-backward-system-60sec.actdouble-slit-screen-backward-2001-artwork.act I am working on another slit-scan experiment using Mandelbrot Set artwork created by another college comrade who was also along for the 2001 ride back in 1968. I will post that item in the near future. Best to all.