Facial expression and animation are important aspects of the 3D environment featuring human characters. These animations are frequently used in many kinds of applications and there have been many efforts to increase the realism. Three aspects are still stimulating active research: the detailed subtle facial expressions, the process of rigging a face, and the transfer of an expression from one person to another. This dissertation focuses on the above three aspects. A system for freely designing and creating detailed, dynamic, and animated facial expressions is developed. The presented pattern functions produce detailed and animated facial expressions. The system produces realistic results with fast performance, and allows users to directly manipulate it and see immediate results. Two unique methods for generating real-time, vivid, and animated tears have been developed and implemented. One method is for generating a teardrop that continually changes its shape as the tear drips down the face. The other is for generating a shedding tear, which is a kind of tear that seamlessly connects with the skin as it flows along the surface of the face, but remains an individual object. The methods both broaden CG and increase the realism of facial expressions. A new method to automatically set the bones on facial/head models to speed up the rigging process of a human face is also developed. To accomplish this, vertices that describe the face/head as well as relationships between each part of the face/head are grouped. The average distance between pairs of vertices is used to place the head bones. To set the bones in the face with multi-density, the mean value of the vertices in a group is measured. The time saved with this method is significant. A novel method to produce realistic expressions and animations by transferring an existing expression to a new facial model is developed. The approach is to transform the source model into the target model, which then has the same topology as the source model. The displacement vectors are calculated. Each vertex in the source model is mapped to the target model. The spatial relationships of each mapped vertex are constrained.

There are several different setups for facial rigs today, joint-based and blendshape-based are two popular examples, both of them fall in the category of geomtetry-based facial rigs. The goal with this dissertation is to attempt to develop a Maya muscle facial rig. Then the rig is tested to examine to see where this rig can be an improvement in relation to other rigging systems. It was possible to create a rig using the Maya muscle system. There was an attempt to reach out to the public and get some opinions but it was to weak so no real conclusions could be drawn from it. This rig was most useful when creating stylized cartoon characters. The Maya muscle rig has several substantial flaws that is weighted against several cons that reveal that this is a niche rig that is useful in some areas but should be completely avoided in the game industry.

With high emphasis on the need of combining recent research and technology regarding automatic facial rig generation with the artistic aspect and the usage of digital humans within film production pipelines, this thesis project presents a scalable blendshape optimization framework that is adapted to fit within a VFX-pipeline, provides stability for various kinds of usage and makes the workflow of creating facial rigs more efficient. The framework successfully generates per-actor based facial rigs adapted towards sample data while ensuring that the semantics of the input rig are kept in the process. With the core in a reusable generic model, gradient based deformations, user-driven regularization terms, rigid alignment, and the possibility to split blendshapes in symmetrical halves, the proposed framework provides a stable algorithm that can be applied to any target blendshape. The proposed framework serves as a source for investigating and evaluating parameters and solutions related to automatic facial rig generation and optimization. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>