0:00

Okay, our next topic is sketch-based modeling.

Â And the work we introduce here is called Teddy.

Â And the problem we want to address here is that 3D

Â modeling is difficult, especially modeling of motion 3D organic shape is difficult.

Â So a typical user interface is like this.

Â So typically, you have three views.

Â And then you have above view, front view, left view and then you

Â put many body sees and you put many edges and create many faces.

Â And then you have to combine many, many commands.

Â And nest with many and those are many parameters.

Â And this can be very useful an idea for a

Â professional production for movies or t.v shows, cars and products.

Â However, if you want to use this kind of

Â system for communication this is way too difficult to to.

Â 0:50

However on the other hand, if you have a

Â pen and a paper you can quickly draw something, something

Â meaningful and more importantly if you look at this kind

Â of image you can infer some geometric information for example.

Â Probably, this face is, you know, kind of lozenge-shaped, then also

Â hands should not be a bit larger head or something like that.

Â You can get general idea.

Â So our idea is to implement this kind of visual

Â intelligence into a computer to make a useful 3D modeling tool.

Â So that's the idea.

Â And let me show you a demo.

Â 1:44

And then as soon as you finished drawing.

Â System mathematical inflated, and then you get this 3D shape, so

Â now, this is already 3D, so you can see it from front

Â or top, or you can also rotate through it, so you get

Â a full 3D shape here, and you can also cut this object.

Â You can also paint it and cut it and you can also add a bump, so in this way you

Â can generate reasonable 3D object just by drawing outline of the

Â intended shape and internally this is standard 3D object presentation.

Â So if you use traditional tools, you have to combine many commands

Â and also you have to manipulate many visual elements, can be very tedious.

Â And let me describe some, little bit individual operations.

Â First operation is creations.

Â From the blank canvas, you draw closed region.

Â And this is the inflated.

Â So if you draw circle and you get a sphere.

Â And if you get long bar or you get bar

Â or it's you can generate this kind of snake shape.

Â And so, in other words, it is basically like this.

Â So if you have a large region system increase a lot and

Â if you get a narrower region, to sustain for it a little.

Â In this way, you get always get a cross section.

Â 4:02

And then, if your input is inside of the object it will be projected and painted.

Â However, if you sort of comes outside on the inside on the

Â side, it will cut the object by, you know, projecting the line.

Â And then this useful for our intersection that I did in

Â this shape or you can make a mouth like this way.

Â So that's a cut operation.

Â And the next operation is extrusion or bump operation.

Â So if you want to add a bump.

Â And you do a closed region, and rotate, and then do a second stroke.

Â So this is two, two stroke operations.

Â First stroke defines a domain, and

Â the second operation stroke defines a silhouette.

Â So, this is basically a sweep or extrude operation.

Â So this the imput it's first throw, second throw, and you will get this.

Â And this is very flexible.

Â Example, if you draw this kind of shape you get a snowman kind

Â of shape and you can also make a mushroom kind of shape this way.

Â 5:26

Another example is a same plate like shape.

Â So, if you draw this domain, and if you draw this shape you get a in a wing shape.

Â And again, you will draw this shape, and then this shape and you'll get the wing.

Â See?

Â This way, you can generate, kind of a bird.

Â And after having some objects, you may want to deform or edit it.

Â In order to do so, we also provide sketch-based operations.

Â So it's called this bend button.

Â So this take two strokes.

Â First one is a left hand stroke.

Â The second one is target stroke.

Â So let's do a left hand stroke, and then do a target stroke.

Â So what system tries to do to form a shape so that lead deforms into groove.

Â And you will get this result.

Â So, in this way you can get reasonable solid

Â shape by sketching, and this deformation to a loose form.

Â So again press bending and left is input, defines and then moves target.

Â And then you will get this, this kind of shape.

Â And you can also refine some of the output [UNKNOWN].

Â So by combining these operation you can get a shape something like this.

Â [BLANK_AUDIO]

Â Let me show you a couple of 3D models' painted results.

Â [BLANK_AUDIO]

Â So, all these models are created using this

Â technique and they're painted using traditional, painting interfaces.

Â And you can see one can generate a reasonable 3D object using this technique.

Â [BLANK_AUDIO]

Â So let me describe its algorithm a little bit.

Â So here's a overview of its algorithm or [UNKNOWN].

Â So this is two-dimensional user input.

Â And then last thing the computer do is fast.

Â Identify an axis of skeleton that discloses the domain.

Â So, center line.

Â On the after computing, this center line, your axis,

Â we lift it, we raise them, in this way.

Â An important point here is that the amount of lifting.

Â Depends on proportional, to the distance to the silhouette.

Â For example, here, the distance is very large, so it gets higher.

Â However, here, the distance is very short, so it's not to get higher.

Â So, in this way, you get visible shape

Â and after that, the remaining task is just simple.

Â We just put an overall shape along the

Â axis and the silhouette to get final result.

Â 8:17

So this is overview.

Â Now let me describe step-by-step.

Â So input is two-dimensional, polygon or polyline.

Â And then, after that, we apply, constrained Delaunay triangulation.

Â This is very simple computation or general to the operations, just triangulate them.

Â And then after that we compute an axis by connecting mid-points.

Â Well this is, again, very simple operation,

Â but very powerful tool for analyzing the shape.

Â And this one, this technique is published could use by a person in 97.

Â And after connecting the mid-points, you get, three kinds of triangles.

Â One is this, conjunction triangles, with no external edges.

Â And another is sleeve triangles, with one external edges.

Â And also, terminal triangles, with two external edges.

Â 10:21

this terminal triangles.

Â So that's a trimming operation.

Â And after our previous operation, you get this idea or shape.

Â And this is where we stand.

Â After you get the center shape.

Â You just lift up the center axis proportional to the distance here.

Â So, if you look up here, you have serrated line and center line.

Â And you lift it up in this way, and

Â this length is a bridge of the surrounding edges.

Â And after that, you just put quarter of a circle in

Â this way and in this way and then just stitch them

Â 11:25

So one possible application is education.

Â For example, in a biology class, the teacher may say this is a bacteria.

Â And then internal select shows it like this.

Â And the students can understand the kind of three-dimensional concept.

Â And then there's the possible application in medical applications.

Â For example, doctor may want to say, this is your stomach.

Â 11:57

And then doctor can say, you know, let's fix it, and so on.

Â And or a dentist may say this your tooth, and that there you have a serious

Â problem here and there, and that you need to remove them, and so on.

Â And one particular interesting application we want to show is teaching of geography.

Â You know, geography is the concept of mountains and valleys

Â and rivers or lot of three dimensional ideas, which can be

Â very difficult to understand sometimes using two dimensional whiteboard, but here

Â if you have a 3D sketching it can be very useful.

Â As an example we want to use a teaching of contour lines.

Â As in you may know it's contour lines, you know, in

Â the two dimensional map, you see lots of lines indicating heights.

Â But it can be difficult to understand what that means.

Â Well here, the teacher can say, now, you have some mountain

Â here, some mountain side view, front view, and top view.

Â So you have one mountain here.

Â And now, let me draw lines indicating equal height,

Â say this is ten meter high, 20 meters, 30 meters, 40 meters.

Â So these lines indicate equal height.

Â And then this is side view and the front view.

Â And if you look, then, from the top, now you see that this is a contour line.

Â And there you can allow many things, like sparse contour lines indicates, you

Â know, gentle slope, and dense contour lines indicate sharp slope, and so.

Â So, yeah.

Â So this is a main application we

Â are thinking of this kind of sketch-based modeling.

Â 14:04

And we introduced polygons mesh based information,

Â another possible approach is using implicit surfaces.

Â So it masters and generates smooth shapes

Â like this one so it generates smooth connection.

Â On these, I can also change the configuration later.

Â And this one is called ShapeShop and published in 2005.

Â And I think application is also available.

Â So I recommend you to try them, too.

Â Thank you.

Â