Notes

The animal was in daily contact with other macaque monkeys and human caretaking personnel.Human movements were recorded from a yearold male human subject.Such techniques have been applied before for the realization of animation movies for cinemas. However, monkey avatars of high quality have only very recently been developed for studies on static face perception, and to our knowledge, this work is the first one exploiting motion capture from monkeys for generating such dynamic avatars.The head model was developed based on the MRI scan of an animal. The scan provides a quite detailed model of the basic shape of the head, but it is characterized by a highly irregular polygon structure, which makes it difficult to control the deformation during animation.In order to obtain a mesh model that can be manipulated more easily, we reduced the number of polygons and created a regularized mesh with clean edge loops. This corrected mesh was adjusted for a neutral pose, and control points were specified that control the mesh deformation during animation.For the regularized mesh, the weighting regions that determine the influences of the individual control points on the mesh could be exactly controlled.This developed lowpolygon model is useful for controlling the animation, but it lacks a lot of highfrequency details that are critical for a realistic <a href="https://www.targetmol.com/compound/δ-Tocotrienol">buyδ-Tocotrienol</a> appearance of the face.This model was further refined by a number of <a href="https://pubmed.ncbi.nlm.nih.gov/34056642/">searchδ-Tocotrienol</a> specific editing steps, including clay modeling, in order to improve D shape details.Using a special tool, additional texture details were added, such as wrinkles and pores. A particular challenge was the development of a realistic skin model that specifies believable color and reflectance properties.Skinsurface textures were generated using photographs of a real monkey as the reference and by painting layerwise color variations of the skin in order to approximate maximally its realistic appearance.Specifically, we used multiple layers of diffusive texture to model the translucent behavior of the skin, separately for the deep layer, subdermal layer, and epidermal layers. For the deep layer, we hueshifted the diffuse texture map toward red colors in order to model the deep vascularization, while the color of the subdermal layers was shifted more toward yellow in order to simulate the fatty parts of the skin.In order to mimic the very thin superficial layer of dead skin, we desaturated the diffuse texture for the epidermal layer.For realistic appearance, it was also important to model the specularity of monkey skin, reproducing how light is reflected from the skin within different facial regions., corresponding to the IOR of water.A final element that was essential for a realistic appearance was the realistic modeling of the fur.The overall appearance of the hair was controlled exploiting three control levels.The first level models the base of the fur, defining the direction of the hairs by control splines and adding some noise to model texture fluctuations and the matting of the fur.The second level models structures consisting of long hair, including the whiskers and the brows, using a smaller number of thick hairs.The commercial package also includes all main textures for the neutral pose, as well as the corresponding textures for face compression and stretching.