hello, this is week 5 of interactive computer graphics. A topic we discuss here is fabrication. So, so far, we have been working on, introduced, discussed computer graphics. So display imagery on the screen. Everything was on the computer screen inside of a computer. So this week, we discussed trying to going out of the computer screen and then try to work on the physical object we can touch and manipulate in the real world. And the background motivation is here, so you know there are so many possible fabrication machines getting available, getting cheaper. So if you have a 3D model inside a computer, you can easily directly print. 3D models as physical objects. For example, if you have a 3D printer, you can get a 3D model. Similarly, milling machines automatically mills the material and then you get the 3D model. And so you have, 2-dimensional patterns. You can easily send it to laser cutter, or cutting machine and you will get nice three- uh two dimensional shapes out of a box. So, here's a list of topics we discuss here. We discussed design with plush toys and design with beadworks and chairs and also discuss soft folding of clothing materials, and also interactive packing, packing method. So first one is a plush toy design. So this work is called Plushie. So the problem to address is that it is very difficult for non-experts, for us to design 2D pattern for stuffed animal appropriately. You know? You want to get a three-dimensional stuffed animal, you need to design two-dimensional clothes patterns. For experts, it may be easy to understand the relationship, but for novice users or no-experience people, it's very difficult to go back and forth between 2D to 3D and then 3D to 2D. So, for the sketch-based 3D modeling and automatic cloth pattern generation. So this is extension of teddy system we introduced. So you just sketch desired shape, and then system generates a three dimensional, geometry. But at the same time, system also generates a corresponding 2D cloth pattern. So if the user print them, cut them, stitch together, and inflate it. And then you'll get the 3D, physical 3D shape. So that's the idea. Let me show you a video. So here's a overview. The user input is two-dimensional sketching input on computer screen. And then, given the user input system automatically generates 3D shape and then corresponding 2D clothes patterns. And then after having clothing patterns, the user sew together and then you get the physical stuffed animal. Here’s a operation. So user interface is very similar to the original Teddy system. User just sketches outline, and then system inflates it. But at the same time you get a two-dimensional cloth pattern, and what's happening here inside is that we learn a simple physical simulation inside. So the system predicts what happens if you stitch them together and inflate it. And then system shows a predicted 3D geometry here. And after having some geometry, you can interactively edit it. Like, like TEDDY system, you can cut object and then system automatically gets 3D shape and as well has a two-dimensional cloth pattern. So user continuously edits the shape, and then system continuously presents a two-dimensional shape. This is an extrusion operations. So here we generate two possible operations. So one is extrusion like this one. So large base and with holes and also, we also support adding extrusion this is useful for making an ear. We also implemented a cover of editing operations such as pulling the shape. So here the system concurrently edits, modifies the 3D shape and also two-dimensional patterns. And this is in- in- interesting so you can actively add or erase a seams on top of a current pattern. So this is interesting I think. So, now you have, we have three pieces and then single 3D object. But if, here the user tries to erase the seam, so which means that these two patches will be merged together. So you will end up having two patches. And system applies this computation in real time. So as user erases a patch boundary, then system merges the two patches together, and then you will have now a two, patches, and the system also applies the physical simulation to the result. So user can also operate directly on the 2D pattern, and then you will get a modified 3D shape. So you can easily directly working on 3D shape, or you can work, directly working on 2D pattern. So this two way editing can be very flexible. And this is an example of modeling sequence. So user first generate a base shape, and then you apply cut operation to get more control. So basically by repeating simple sketching, editing operations, you can generate reasonably complicated shape. Here we, we did not show in this video, but in the actual printout, system also gives, hints or information, which, which edge to be connected with which end. So, the construction is also guided by the computer generated annotations. So after having this 3D model, the user print this pattern into paper or cloth and then you will manually create 3D stuff animal. So this is 3D model, and then this is a generated real physical stuffed animal. So you take four or five hours to get this. And, you can also create a big one by using, you know, inflation. So this is a big balloon, like two meter size, a big balloon. So traditionally this kind of balloon is designed by professional designers, and it requires many testing and trials and prototyping. But here, the computer can take care of the prototyping and simulation. So even inexperienced people can design its own- his or her own balloons. So we learned our simple study. So, we asked kids to design their own stuffed animal. So traditionally, these people can buy existing pattern and they create, the stuffed animal. It was almost impossible to design new original character, stuffed animal. But here, you know, even students, kids can design their own stuffed animal. And after finishing the design, you know print then cut and then stitch together, and then you will get a final 3D model, oh no, no, final plush toy. So, you can design their own original model. Yep. So, let me briefly, describe the algorithm. For the inflation algorithm, for the inflation simulation, we use a very, very simple, basic mass-spring method. So, cloth 3D model mesh vertices move outward all the time by air pressure or cotton pressure. So it tries to inflate. But at the same time system tries to pull them back, depending on the edge length. If edge length is too long then it will pull back. And then we repeat these two processes, and then at the end you will get a stable result. We must say that this simulation is not accurate simulation of real physics. There will be more other advanced physical simulation methods, but you can get more accurate result by using more accurate methods but it is also interesting to see that you can get basic result with basic simple simulation method. And another interesting issue is that adjustment of the 2D sha- 2D pattern. So, so, algorithm first takes user input- this red one and then directly use it as a 2D pattern. However, if you start with 2D pattern and inflate it, you know, inflated it, you inflate in Z direction but if you pull in Z direction then X Y frame should become get smaller right? So in order to prevent it, the user- system tries to adjust the shape to compensate this difference. So after, after the initial configuration, system tries to gradually inflate the 2D pattern so that the resulting 3D inflation result matches exactly to the 2D input sketch. So that's the, you know, inflation algorithm you saw in the video. So this shape adjustment is very important. You know, if user draw let, box, as a input, and if you directly use this box as a 2D cloth pattern, then if you generate a 3D shape or 2D real shape, you will get shape. So resulting shape is not exactly match with this rectangle. But if we apply the shape adjustment mesh algorithm, then system automatically inflates the input 2D shape. Then physical result will, fabcrication result matches, more closer to the rectangle. So, yeah, this is interesting. So if you want to have a rectangular, pillow, you should start with this kind of pattern, not start from here. So, to learn more, original paper was published as Plushie: an Interactive Design System for Plush Toys. And this work, it was strongly inspired by previous work on paper craft model. So this work making paper craft toys from meshes using Strip-based approximate unfolding. So this one starts from a given 3D model, and then automatically generates a 2D paper craft pattern. So you can generate interesting, 3D shapes just by using paper craft. And we use a surface flattening method to generate moving from 3D to 2D. And surface flattening is also a very popular topic in computer graphics. It's very useful to compute a texture map coordinates, and if you learn more, one starting point would be this mesh parameterization method and their applications. So that's right this week ah this video.
