Han, Donghui (2017-05). Perceptual Effects in Physically Based Animation with Rigid and Deformable Objects. Doctoral Dissertation. Thesis uri icon

abstract

  • We perform four psychophysical studies to investigate the perceptual effect of factors in the rendering and simulation stages of physically based animation production. Our study provides helpful insights in how to improve visual plausibility or reduce computational cost, which may allow artists to adjust their designs to enhance or minimize the perceived deformation in a model, or to choose a more efficient dynamics model and simpler mesh used in simulation without harming the visual plausibility. In our first study, we find that appearance can potentially influence people's sensitivity to differences of deformation as well as subjective rating of softness. Further analysis shows that, in simple scenarios, the effect of low-level visual details in appearance can be dominant, even if high-level information delivered by appearance has the opposite implication. Another experiment shows that as the number of objects in a scenario increases, objects are perceived to be stiffer. In the second study, we quantitatively measure how different low-level visual details can influence people's perceived stiffness of a deformable sphere under physically based simulation. We find that checkerboard pattern with certain combinations of spatial frequency and contrast can reduce the perceived stiffness. Our study further shows that adding a high-contrast checkerboard background can reduce such effect. In our third study, we discover that the resolution of a mesh used in the simulation of deformable objects can be reduced to a certain level without being noticed. For complex deformation, it is easier for people to recognize such reduction. Lastly, we verify two hypotheses which are assumed to be true only intuitively in many rigid body simulations in our third study. I: In large scale rigid body simulation, viewers may not be able to perceive distortion incurred by an approximated simulation method. II: Fixing objects under a pile of objects does not affect the visual plausibility. Our analysis of results supports the truthfulness of the hypotheses under certain simulation environments, but discovers four factors which may affect the authenticity of these hypotheses: number of collisions simulated simultaneously, homogeneity of colliding object pairs, distance from scene under simulation to camera position, and simulation method used.
  • We perform four psychophysical studies to investigate the perceptual effect of factors in the rendering and simulation stages of physically based animation production. Our study provides helpful insights in how to improve visual plausibility or reduce computational cost, which may allow artists to adjust their designs to enhance or minimize the perceived deformation in a model, or to choose a more efficient dynamics model and simpler mesh used in simulation without harming the visual plausibility.

    In our first study, we find that appearance can potentially influence people's sensitivity to differences of deformation as well as subjective rating of softness. Further analysis shows that, in simple scenarios, the effect of low-level visual details in appearance can be dominant, even if high-level information delivered by appearance has the opposite implication. Another experiment shows that as the number of objects in a scenario increases, objects are perceived to be stiffer.

    In the second study, we quantitatively measure how different low-level visual details can influence people's perceived stiffness of a deformable sphere under physically based simulation. We find that checkerboard pattern with certain combinations of spatial frequency and contrast can reduce the perceived stiffness. Our study further shows that adding a high-contrast checkerboard background can reduce such effect.

    In our third study, we discover that the resolution of a mesh used in the simulation of deformable objects can be reduced to a certain level without being noticed. For complex deformation, it is easier for people to recognize such reduction.

    Lastly, we verify two hypotheses which are assumed to be true only intuitively in many rigid body simulations in our third study. I: In large scale rigid body simulation, viewers may not be able to perceive distortion incurred by an approximated simulation method. II: Fixing objects under a pile of objects does not affect the visual plausibility. Our analysis of results supports the truthfulness of the hypotheses under certain simulation environments, but discovers four factors which may affect the authenticity of these hypotheses: number of collisions simulated simultaneously, homogeneity of colliding object pairs, distance from scene under simulation to camera position, and simulation method used.

publication date

  • May 2017