Thursday, November 6, 2014

Class 10 Final: monocular depth cues

Example 1: Occlusion.

In this screenshot from Meshmoon Rocket, we see two different 3d car models. The red version is clearly in front of the green one and from the camera's perspective. If I were to move further to the right in this frame, the green more would be further revealed. This motion would show the parallax element of 3d motion graphics. 

Example 2: Size Differences.

In this shot, there are three visible stoplights. The closet light pole is the largest in the screenshot as far as # of pixels comprising it is concerned. The background posts are not only shorter, but also significantly thinner. This is the 3d graphic 's way to show that the post facing me is closer than the other ones in the intersection. 

Example 3: Shading.

The tree in this screenshot shows how 3d graphics takes advantage of shading differences a on different parts of an object. There is not a ton of detail in the bush shape at the top of the tree, and this can be shown by the fact that one can easily point out the differences in color along clear lines in the tree. Each polygon created here however is colored in with a different shade of green. The one at the highest point of the tree is the brightest shade of green, as it is closest to the light source.. In this case that is the the virtual sun.


Example 4: Linear Perspective.

As referenced by Prof. Walsh in his text, this element of 3d graphics is taken straight from the Renaissance. 3D point perspective with a vanishing point in which numerous lines head towards is shown in this example. The lines from the curb and sidewalk are where this vanishing point can most clearly be seen. 


Example 5: Texture Density.

In this screenshot, the property of texture density in 3d graphics shown quite clearly. From straight on, these yellow light on this sign are equidistant apart from each other. When I look at them from an angle however (as in the case of this screenshot) they seem to cascade together. The closest light is not only biggest, but it has the most space between it and the next light. the rest have just a fraction of space next to them. 


Example 6: Atmospheric Perspective.

In this example from Meshmoon we can see that the bricks closest to the right of the frame and not only bigger and closer to the virtual camera, but more clear than than the rest as well. The bricks further out and fuzzier and begin to fad together as the texture density of them increases. This is a way a computer can save power, as it only needs to render out what the character is close to, and not necessarily everything at once, it also emulate near-sighted vision in humans.


This is a final  exercise from the Immersive Education course that I am taking at Boston College. The course is called Discovering Computer Graphics. For details, visit the immersive BC portal at http://ImmersiveEducation.org/@/bc

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