How to move a face in simulated 3D

[Rasheed]

I'm trying to solve the problem of moving a character in simulated 3D. I thought a moving face is much easier than a whole body, so I started with that. Here's what I've come up with so far:

The lines on the circle are meant as guide for drawing the face. I've put in the nose as well. It was create by using 9 interpolated switch layers:
* center
* up, left, down, right
* up-left, down-left, down-right, up-right
Now almost any movement of the face can be made, as long as the nose remains in view.

I've tried include the eyes in the switch layers as well, but that didn't work, because in some poses one or both eyes disappear from view. Interpolation then leads to only showing one eye, while two ought to be showing. I guess the eyes, eye-browes, ears, mouth etc. all have to be drawn in separate layers and positioned to match the basic face design.

Of course, in the final animation, you'd remove those ugly black lines from the swithed layers, or perhaps get rid of these switched layers all together and use them only to design the right poses.

[Rasheed]

Here I have created a style to remove the facial guides easily, just by changing the line color's alpha value to zero. Furthermore, I have added a second switch layer, with up, center, down, left and right only. Both the switch layer for the face background as that of the snout are switched together.

Now I only have to add a nose, mouth, eyes, eyebrowes, ears, whiskers and hair in switch layers and create them for 9 poses.

And oh, before I forget, you can't just switch from one layer to another. If you switch from right to left, you must insert center too, otherwise the snout is interpolated much too small in the center position.

[Nichod]

Why interpolate at all? Then you wouldn't have to worry about the issues of losing an important facial feature. All you have to add is another few switch layers. Though I realize what you are attempting is to simplify the workflow;)

Brian

[Rasheed]

Well, I can use interpolation between those 9 poses to draw as many poses as I want, but with more precision and detail. I want to use interpolation as rough animation here, to quickly see what works and what not.

[jahnocli]

I think it's a fascinating idea, and I'm interested to see what you will do next.

J

[Toontoonz]

Perhaps give Moho Tutorial 6.8 a try.

[Rasheed]

Sometimes drawing volume in a flat drawing appears more real than displaying a 3D object. Especially if a face or an arm is rotating out off the plane of view, some detail tend to get lost in the jungle of tiny lines and pixels. By slightly modifying the foreshortening the picture will be clearer, although not precisely resembling foreshortening of an animated 3D model.

I thought there must be a quicker way to draw turning faces than what I've done before. Maybe a grid might help me, so I drew a globe with grid in a vector layer. The grid consists of circles that either have common points North-South or East-West.

Every point of intersection is actually the middle of the face in a certain turning pose. If the face is looking straight at you, the horizontal and vertical lines through this midpoint are straight lines. If it's looking at an angle, these lines become curves, as you can see on the globe.

Besides being the midpoints of the face in a certain turning pose, the lines/curves can also be used to determine where the details should go when the face turns. Or to be more precise, the surfaces these lines enclose give you an idea of proportion and distortion by perspective (IOW how big and what shape). It isn't exact, so you'll have to experiment a little to see what works. On the whole I think it's far easier for a (at the present) poor draughtsman like me than drawing without such an aid.

To prove my point I used this grid-on-a-globe to draw a rough animation of a face, turning left and right.

[Rasheed]

And here is that last animation with eyes, nose and mouth.

Remember, this is still a rough animation (because of the smooth interpolation), but it's not too bad.

The eyes are a bit too small at the edges. I've used the grid as described above, but it seems it is still not the correct one. However, it's relatively easy now to tweak the animation so that it looks right.

If anyone has a better idea (other than modelling a 3D version of The Mouse), I'm all eyes.

[cribble]

I usually do this with my character designs. Except i don't draw multiple angle, i only use 3 main angles (front, front-ish side-ish and side) and animate, with aid of onion skinning, to each drawing.
I make sure that each layer has the same amount, or more, points to allow me to get from A to B easliy, while maintaining the characters shape. I didn't use swith layers, because 1) The interpolating (sp) works when ever it feels like (not a bug, i'm just being sarcastic) and loses its details here and there when it does the process; and 2) i'm awkward. The results are as below:

http://www.freepgs.com/cribble/moho/char-devlp.swf

This is an early, rough version. I've lost the original animation files, but still have the character files, so i can't really share my example. Hopefully what i've described is good enough.

[Rasheed]

Ah, I understand, you use normal curve interpolation between consecutive vector layers.

Hmm, in my experience switch layers are more flexible, in the sense that you can rearrange the animation more easily than in the Points animation channels and still interpolate between keyframes.

I realize (again) that there is really no substitution for hands-on experience with drawing real-life objects (and people). No clever method is going to replace that. If you have never studied how objects should be drawn when they rotate, you can only fail to do so behind your computer screen.

[Rasheed]

I've created an animated GIF of a rotating sphere, with the center of the face marked by a black dot. The sphere rotates from -90 to 90 degrees along the Y-axis and up and down between -90 and 90 degrees along the X-axis. The angle increments by 22.5 degrees per frame (0.32 s/frame, first frame 1.28 s).

(Wings/Moho source file)

It shows how the surface of a sphere moves in real 3D space. The positions roughly coincide with the points of intersection in the sphere grid (see above).

I realize now that the sphere grid only indicates where the midpoint of the face is, not how the sphere can be divided into equal-surface sections. Therefore you cannot use the sphere grid to redraw the face pointing in another direction.

[Rasheed]

Another approach is to create a special 3D body in Wings3D, a sphere with sticks pointing outwards. You can rotate this sphere in Moho and use the sticks as a reference for a turning face animation. It is a kind of rotoscoping (using an existing animation or real-life action to create another animation).

The result isn't very realistic, but nevertheless, it resembles somewhat a face turning left to right, while showing its chin.


Look what happens if you reduce the number of inbetweens (and thus speed up the action):

So for this to work, you have to make speedy turns. But that's ok, because most head turns in traditional 2D animation are speedy turns (and those animators use other tricks as well to reduce the workload).

This method is rather quicker than the previous ones, because there are enough visual clues where to put the mouth, nose and eyes (and ears as well, but I left those out here). The only drawback is that you have to create the Wings3D model. But once that's done, you can use it as often as you like.

Remember, I wanted a method to draw a face from all directions, and I think this latest method seems to be pretty close to the one that I want.

BTW I've used no switch layers this time, but simply vector layer interpolation. That works just fine for simple animations. (Thanks cribble, for that tip.)

[Rasheed]

Using the last method, one could be under the impression that putting more sticks in the sphere would lead to better animation.


However, this seems not to be the case. If you have too many points to orientate yourself, you tend to put the bits of the face in the wrong place and those bits are going to "wobble" during the animation (see in the example animation).

It seems more important that the relative positions and proportions of the eyes, nose and mouth are maintained than that these are exactly spot on their positions.

However, this exercise was still usefull, because I saw that you should position the eyes first (that is, after you've determined where the midpoint of the face is during the turning of the head), followed by the nose and only then the other parts of the face.

Maybe it is enough to just position a triangle on the turning sphere with only a few sticks in it as orientation points -- to draw the rest of the face. The cornerpoints of that triangle are then the midpoints of the eyes and the tip of the nose.

I will explore this idea next time.

[Rasheed]

Look what happens if you use a series of lines instead of the actual shapes for rotoscoping.

I simply aligned the center of each layer containing a shape with the correct endpoint and used layer translation to translate the shape.

The triangle gave me an indication of the proportions. I created the animation of the red lines by tracing the multi-pinned sphere I described earlier. After that, I animated by translating the layers containing the eyes, nose, mouth and ears (each in its own layer) and modifiied the shape of each shape at the end of the turn with the Move Points and other points tool. I removed the left ear at the appropriate keyframe.

Judging from the smoothness of this animation, it seems to be the correct way to animate a turning head if you want to use rotoscoping. Simple and easy

[bupaje]

@rasheed - thanks for your experimenting. I am finding it interesting.