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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.

After doing the 2001 slit-scan project (https://forums.hash.com/topic/53303-2001-slit-scan-effects-simulated-in-am-with-mufoof/) using resurrected 2001 artwork (https://youtu.be/dujQGB-2EXw), I wanted to try some other graphics. The Mandelbrot Set is a wonderful source of interesting imagery. My college roommate, Mike Segor, who also went to that 1968 showing of 2001, had sent me some Mandelbrot work. Grist for the mill. He also contributed music for the final movie. The artwork: John Knoll has a fascinating video about slit-scan techniques (and shows a graphic of the Trumbull 2001 set-up at 5:07): https://vimeo.com/391366006 He discusses various approaches including circular slits and other, similar, symmetrical geometry like the Dr. Who Tardis/police call box/tunnel sequence. For this experiment, I decided to start with the 2001 slit-scan technique and then try circular slits. Did not use the soft-edged slit approach as much rendering on this project was complete before that idea was tested. The movie breaks down into these parts: Vertical slit scan created on left half of screen, flipped and inverted onto right half of screen; Composite=Add. Has the expected acceleration effect created by moving the slit-screen model element across the artwork during MUFOOF frames and moving the artwork between frames: Circular slit scan (full screen effect), artwork movement between frames; has sweep, is pretty, but no dynamic acceleration: Another circular slit scan clip overlaid on first circular slit scan clip with Composite=Difference; more dynamic because of counter-movement, but no real acceleration: Circular slit scan with slit-screen movement Right to Left during each MUFOOF frame, artwork movement between frames; has dynamic acceleration but is asymmetrical: Circular slit scan, slit-screen movement diagonally Lower Left to Upper Right during each MUFOOF frame, artwork movement between frames; has sweep and dynamic acceleration but is also asymmetrical: I made other attempts at a symmetrical set-up, but they did not give a dynamic acceleration effect: 1. Moving artwork away from camera faster than slit-screen (z-axis), exposing more artwork, in each MUFOOF frame; moving artwork between frames (x-axis). 2. Changing size of circular slit, exposing more artwork, in each MUFOOF frame; moving artwork between frames. 3. Moving circular slit from below centerline to above centerline in each MUFOOF frame; moving artwork between frames. Has the virtue of being symmetrical horizontally, though not vertically: 4. No slit, just an open circle in screen and no movement of screen in MUFOOF frames; moving artwork between frames. Has sweep but no acceleration: I wanted to try one more effect before giving up on finding a symmetrical set-up that would give dynamic acceleration — rotation of artwork 360 deg around the z-axis during MUFOOF frames, moving artwork left to right between frames, and using the open circle shown above. This idea went down a whole new rabbit hole where I spent several days, but it led to what appears to be a generalized solution for simulating slit-scans that create dynamic motion. Initial results looked very strange. Then I realized that as the animation progresses, the artwork moves left to right as intended but the rotation point travels with the artwork and rotates it out of the camera FOV. After thinking about that problem, I decided the solution might be an additional bone to rotate the artwork (which I named Pivot) while the artwork itself is assigned to a child bone of the Pivot bone. That worked and the result has dynamic acceleration. A still from the final part of the movie: Here is the movie: https://youtu.be/aD8xUaaGIF4 Here are files for the open circle scan with pivot rotating the artwork 360 deg during each MUFOOF frame, artwork movement Left to Right between frames: circle-no-slit-scan-MUOOF-backward-mandelbrot1-rotateArt360-sys3.chocircle-no-slit-art-sys-MUOOF-backward-60sec-rotateArt360-sys3.actcircle-slit-screen-backward-artwork-moveL2R-sys3.actcircle-no-slit-screen-art-mandelbrot1-system03.mdlcircle-no-slit-mandelbrot1-rotateArt360-sys3.pre Mandelbrot artwork appears above. But wait, there’s more. After successfully moving the artwork in relative space using the parent Pivot bone and then moving it in absolute space using the child bone in the second action, I realized this approach could be used for any slit scan animation, including the original 2001 project. Proved to be a bit more complex than that simple statement. I revised the 2001 slit-screen/artwork model with a new parent bone (Pivot) for the Artwork child bone. Now the slit would be stationary, the artwork would move 6” during MUFOOF frames, and the artwork would be moved an absolute amount between frames. Test renders did not look right. In the old method, the slit-screen element moved and the artwork was stationary. In the new method, the slit-screen is stationary. Where should that slit be located? For simplicity I decided to try changing the camera location on the x-axis. Eventually I found that moving the camera +3” on the x-axis gave test renders that were substantially similar to the previous 2001 slit-scan results. However, the image did not reach all the way to the center of the screen. Time to modify the model and MUFOOF action to allow for further experimentation. I added a new bone (System2) to the slit-screen/artwork model to be the parent of all model elements so I could move the whole model during the MUFOOF action. At action start, the model was located at -3” on the x-axis (and the camera was returned to zero in the cho). I experimented with end-of-action values for bone System2; eventually +3” gave the desired result — these are the same values as in the original move of the slit-screen element, except now we are moving the whole model during MUFOOF frames. This model move is analogous to panning the camera slightly during its travel down the track which Trumbull mentioned. Here are revised 2001 slit-scan files using the new method: soft-slit-scan-backward-2001artwork-60sec-PivotSystem2.chosoft-slit-screen-2001artwork-system2.mdlsoft-slit-screen-backward-2001-artwork.actsoft-slit-screen-MUFOOF-backward-60sec-movePivotR2Lsys2L2R.actsoft-slit-artwork01.tgasoft-slit-scan-backward-2001artwork-60sec-PivotSystem2.pre Here is the movie created using the new method which is substantially similar to the demo movie of the soft-edged slit-screen in the 2001 post: soft-slit-scan-backward-2001artwork-60sec-PivotSystem2.mov As the I Ching says, persistence in a righteous course brings reward.