Jan. 14th, 2022
Pixar Lamp video part 1: initial ideas + design calcs.
"Don't hang things from the sprinkler pipe." - MIT EHS
So Fischer and I made this Pixar Lamp — for our 2.74 Bio-Inspired robotics final project. And ever since we did this I've wanted to make a little video with my camera that replicated the Pixar Lamp intro where it bounces on the letter "I." The idea is to just have the lamp jump up and down on a letter "I" that's the correct scale compared to the lamp, but also we don't want to replicate all the motions because it's way too complicated. We went for a 2D simplification where the lamp just jumps up and down continuously on a platform behind the light-up letter "I" and that's kinda where we got for 2.74.
The problem with the platform right now is it requires this huge linear rail system in the back to constraint it and a bungee that helps it jump up and down. The lamp essentially pumps energy into the springiness of the bungee and the spring makes it look like its jumping up and down. For the video I kinda want to get rid of the linear rail and suspend the lamp from the ceiling with four bungees that allow it to jump up and down while also somewhat constraining it so it doesn't jump all over the place. The main reason is because I don't want to edit out the whole big linear rail system we came up with, we could also consider a simpler looking linear rail that would be easier to edit out / look better for the camera.
The two ideas are drawn above, the first idea is harder and has a lower chance of working but might look cleaner on camera. It's possible we can get the right angles of bungee to make the system stable enough. We'd also need a way to anchor the bungee which we don't currently have. The second idea has a higher chance of working but might look worse, it also might be more expensive if we make it from scratch.
If we take a caliper to the shafts we currently have they're about 0.473in ~= 12mm shafts, and they're spaced ~5.48 inches apart (center-to-center). Checking the amazon link from the part confirms the 12mm shaft diameter. If we don't want to spend too much money, we could just re-make the stand, remove the linear rails, and make something that looks nicer. The wooden back and the wiring is really the part that won't play well on camera. We could, now that I think about it. Even temporarily bolt them to the drywall in the room, hm... (sorry facilities).
If we just move the rails from off the structure to somewhere else (the wall, a flat board we paint, etc) we could even just measure the distance between the inner faces of the rails (like seen above) instead of trying to eyeball the center-to-center distance ;) ! That seems like the best option since we already have the rails and the correct size bungees for this idea. Time to un-drill the rails from the wood whoooppp.
So the other things I need to assemble this are like a wooden board (1m by like 7in) of some sort, and green paint to paint it like a greenscreen. Both of these things I think I can find on campus, the green might need to be mixed with white to get the color we need. But before any of that we should unwrap the green-screen (so we can match paint colors).
Here's the setup with our two GVM 680 lights and the "green screen" from amazon. We want to take some photos in this light for fun but also so we can match the color to a paint color. The lighting is set to 4500K, so we can set the camera to around that and take some shots on the Canon 70D.
Here's a shot of the Pixar lamp, we suspend it from the ceiling with strings. The lamp twisted about and was very hard to actually get hanging straight even with the foot on the ground which makes me think the linear rails is a good idea instead of the bungees.
Using a random online color picker/tester/detector thing, we figured out our green screen in these lighting conditions is roughly #b4f480 hex. This is good to know. The next step is to find paint the same color (we might actually just bring the tarp to Home Depot + scan it) and to build the rails, but that's for a later day! 'Till next time.
#colors #film #photography #pixar