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Introduction
Pasting UI
Animated
Surface
Pasting
Cylindrical
Surface
Pasting
Quasi-
Interpolated
Surface
Pasting
The Direct
Manipulation
of Pasted
Surfaces
Papers
Talks
Images
People
Introduction of Surface Pasting
Surface pasting is a composition method in which a feature surface is
attached on a base surface to provide details on the underlying
surface. The base surface can be a single surface or a composite surface.
After pasting, the original underlying surface is not changed and the
feature surface retains the character of its unpasted shape and reflects
the topography of the underlying surface as well (see the
Surface Pasting page
for more details on how surface pasting works, or see Chapter 2
Section 3 of my
Thesis).
How Pasted Surfaces Behave
The main idea of this research is to test how pasted surfaces behave in animation. Thus, I built a skeleton of a puppet, then put skin on top of the skeleton as a base surface and finally pasted the facial features, such as eyes, nose, ears, and lips, and fingers as feature surfaces. After setting up the system, I generated an animation to test the pasted surfaces with deformation of the head and moving fingers.
Animations
The idea of this animation is based on The Scream by Edvard Munch. The animation starts with a man standing on a bridge. The man seems to be looking for something. Suddenly, there is a very bright flashing light. The man gets scared and does not know what to do. He just holds his head with his hands. At this time, some strange things happen. His head gets deformed because he squeezes his head too hard and his head does not return to its normal shape after he removes his hands. He attempts to shake his head to make it normal. However, it does not work. So, he pulls both ears to stretch his head outside. He releases his hands after he cannot stretch his head anymore. The width of the head is restored, but the head is shortened because the man stretched his head too much. Then, he holds his chin with one hand and pull the top of his head with another hand to elongate the head. Afterwards, the man's head goes back to normal shape and size. The man is glad that there is no more exotic things happened, everything becomes normal.
For this animation, I built forty-two keyframes and generated one hundred and ninety-one inbetween frames. The total run-time of the animation is approximately thirteen seconds. Notes that the total number of inbetween frames has been increased to three hundred and four because the quick time movie has been converted to mpeg movie for faster running time.
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| Normal Animation (with Fingers Distortion) | Normal Animation (without Fingers Distortion) |
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| Zoomed Animation (with Fingers Distortion) | Zoomed Animation (without Fingers Distortion) |
Results
The facial features behave as we thought when the head is deforming. The following figures show the facial features in differents poses.
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Although the pasted surfaces behave reasonably in this animation, there are somethings that an animator has to take care of when making an animation. For example, the following figures show the original head with the mouth open wide and the stretched head with the mouth open wide. In the figures of the right column, you will see part of the lip touches (and sticks into) the nose. The reason is the height of the head is shortened, so the nose and the mouth get closer and closer and then they stick together.
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Moreover, an animator has to take care of when designing features, especially hierarchical features. For example, the eye of the puppet is formed by pasting three surfaces hierarchically. Normally, the pupil of the eye lays inside the white of the eye (as shown in the figures of the left column). However, as the eye narrows, the pupil bulges out beyond the white of the eye in the figures of the right column. The reason is the directions of the normals has changed to the sides of the eye that caused the feature to distort in an unwanted manner.
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In my initial animation, the fingers did not behave correctly. The following figures show the distortion when the fingers act a grasping motion. As you can see, the fingers got fatter. In this animation, the relative sizes of the finger domain and the hand domain are constant.
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