CG Class 30, Mon 2017-11-27

1   Thanksgiving trivia questions

  1. When the native American Squanto greeted the Pilgrims in March 1621, what language did he use?
  2. Where had he learned it?

2   Videos

  1. 3D Object Manipulation in a Single Photograph using Stock 3D Models (Siggraph 2014).

    From here Photo-editing software restricts the control of objects in a photograph to the 2D image plane. We present a method that enables users to perform the full range of 3D manipulations, including scaling, rotation, translation, and nonrigid deformations, to an object in a photograph. As 3D manipulations often reveal parts of the object that are hidden in the original photograph, our approach uses publicly available 3D models to guide the completion of the geometry and appearance of the revealed areas of the object. The completion process leverages the structure and symmetry in the stock 3D model to factor out the effects of illumination, and to complete the appearance of the object. We demonstrate our system by producing object manipulations that would be impossible in traditional 2D photo-editing programs, such as turning a car over, making a paper-crane flap its wings, or manipulating airplanes in a historical photograph to change its story.

3   Chapter 12 slides ctd

  1. 12_5 Rendering overview.

    At this point we've learned enough WebGL. The course now switches to learn the fundamental graphics algorithms used in the rasterizer stage of the pipeline.

4   Chapter 13 slides

  1. 13_1 Clipping.

    A lot of the material in the clipping slides is obsolete because machines are faster now. However perhaps the rendering is being done on a small coprocessor.

    Big idea (first mentioned on Oct 20): Given any orthogonal projection and clip volume, we transform the object so that we can view the new object with projection (x,y,z) -> (x,y,0) and clip volume (-1,-1,-1) to (1,1,1) and get the same image. That's a normalization transformation'.

  2. 13_2 Polygon rendering.