Analytical Geometry with POV-Ray
Righthanded and Lefthanded Systems of Coordinates
and the Cross Product
Basics on the handyness of coordinate systems
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The lefthanded coordinate system:
This is the default of POV-Ray.
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The lefthanded coordinate system
- the default of POV-Ray
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pros: The students can start easily:
the x axis and the y axis are pointing in the same directions
as they used to do in their exercise books.
Many commercial 3d graphic programs (i.e. Cinema 4D) use it too.
cons: The cross productin physics is defined for righthanded coordinate systems!
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The righthanded coordinate system:
This can be made in POV-Ray by changing the camera as follows:
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The righthanded coordinate system
by changing the camera values of POV-Ray
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camera { // for diagonal view
angle 18
right -x*image_width/image_height
sky <0,0,1>// right handed !
location <20.0, 20.0, 20.0>
look_at <0.0, 0.0, 0.5>
} // end of camera -----------
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cons: 1. The students have to learn by new:
the x axis and the y axis are not pointing in the same directions
as they used to do in their exercise books.
2. Scenes, designed for a lefthanded coordinate system,
cannot be changed easily for righthanded scenes, because all objects
must be tranformed accordingly!
3. The templates scenes from the "Insert Menu"
and from my "Insert Menu Add-on" must be changed accordingly.
pros: In physics is often(but not exclusively) used a righthanded cross product defined for righthanded coordinate systems!
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The cross product in a lefthanded coordinate system:
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The cross product in a righthanded coordinate system:
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The cross product in the standard
lefthanded coordinate system in POV-Ray
Scene for POV-Ray:
".txt" file or
".pov" file
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The cross product in a
righthanded coordinate system
after changing the camera values of POV-Ray
Scene for POV-Ray:
".txt" file or
".pov" file
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