How do I draw 3D shapes?There are many ways that you can draw 3D shapes. Two of the most common methods are wireframe/polygon and ray-tr
aced graphics. In this tutorial, you'll learn the basics of each. For much more detailed information, please visit our 3D Section.
What are wireframe graphics?Wireframe graphics, and the related polygon-fill graphics
, are fast and relatively easy ways to draw three-dimensional shapes. Their main advantage is speed; they can run reasonably well even on an underpowered old computer, such as a 286!
Wireframe graphics are drawn by using matrices to store a set of three-dimensional points. These points are then converted to the two-dimensional coordinates of a computer screen and connected using lines. Especially when rotated, wireframe models give a
good view of the object that they are modelling.
What are polygon gtaphics?Polygon graphics are just like wireframe graphics except that they connect the polygons formed by the points rather than the points themselves. When shaded properly, polygo
n graphics can look quite realistic. In addition to shading, texture mapping can be applied to the polygons to create further realism.
How does ray-tracing differ?Ray-tracing uses a very different method to produce images. Instead of just plotting
points and connecting them, ray-tracing excruciatingly determines the color of each and every pixel in the image! That might not sound too bad, but just remember that there are over 300,000 pixels in a 640x480 image.
To calculate the color, ray-tracing draws an imaginary ray of light back from each pixel. Through scripts or programs, the ray-tracer is made aware of objects in its path. These objects are mathematically perfect and include shapes such as spheres, cones,
cylinders, lenses, planes, and more. Using information about the relfection and refraction that occurs at each object, the ray is bounced around until it arrives back at its source. This process takes a long time even on fast computers, but yields result
s that are so mathematically perfect as to be surreal. Often, as with polygon graphics, texture mapping is used on the images to give them a more real look. For more information, visit The Online POV-Ray Tutorial
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