XYZ coordinates
XYZ coordinates
I have an offtopic question i didnt check how is it in other engines but is it common for them to use that set fo coordinates ?
http://www.knupps.net/xyz-coordinates.png
becosue in my Physics classes (studies) we use such version :
http://www.we-r-here.com/cad/tutorials/ ... z_axes.gif
and ofcourse some other wird based on circle (for 2D) and cylinder (for 3D wich is ofcourse that circle but spread in tird deminsion) etc.
it comes to my head while drinking tea ;]
http://www.knupps.net/xyz-coordinates.png
becosue in my Physics classes (studies) we use such version :
http://www.we-r-here.com/cad/tutorials/ ... z_axes.gif
and ofcourse some other wird based on circle (for 2D) and cylinder (for 3D wich is ofcourse that circle but spread in tird deminsion) etc.
it comes to my head while drinking tea ;]
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graphics engines and cards all use an X=left-to-right, Y=up-and-down, Z=in-and-out coordinate system. This is so because X is seen as the horizontal coordinates of the screen itself, Y the vertical. Z is the extra dimension and that leaves z for depth.
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Re: XYZ coordinates
Those two are the same coordinate systems. The second image is just rotated.MarcinS wrote:
becosue in my Physics classes (studies) we use such version :
the 1st image shows a coord system used (e.g.) by Irrlicht...
the 2nd image shows a coord system used (e.g.) by 3DSMax...
that's the reason why you have to rotate 3ds meshes around the X axis by -90° (in most cases) !!!
well, if you're using Irrlicht for the graphics (Y up) and your physics engine uses the other coord system (Z up) that shouldn't matter, as long as you use the same axis for up, left and forward...
e.g. you use Y in both engines for the up vector, then the physics world will be rotatet by 90° and also the gravity, but you will never see this because the graphics engine will show you this world correctly with Y as the visible up vector...
you understand what I mean ???
the 2nd image shows a coord system used (e.g.) by 3DSMax...
that's the reason why you have to rotate 3ds meshes around the X axis by -90° (in most cases) !!!
well, if you're using Irrlicht for the graphics (Y up) and your physics engine uses the other coord system (Z up) that shouldn't matter, as long as you use the same axis for up, left and forward...
e.g. you use Y in both engines for the up vector, then the physics world will be rotatet by 90° and also the gravity, but you will never see this because the graphics engine will show you this world correctly with Y as the visible up vector...
you understand what I mean ???
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IrrExtensions:
http://abusoft.g0dsoft.com
try Stendhal a MORPG written in Java
IrrExtensions:
http://abusoft.g0dsoft.com
try Stendhal a MORPG written in Java
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That would be nice, however there's not just Y-up or Z-up, but also left-handed and right-handed. And translations between the latter can be rather complicated.
The usual way is to negate one of the axes, which transforms the handedness, but it introduces many more problems: Front-facing will become back-facing and vice versa. So all faces have to change their orientation... Moreover, rotations need even more changes, so if you want tp transform right-handed animations into left-handed systems, give the ms3d loader a check, I've gathered much information from various websites and hopefully made all the necessary changes there.
BTW: Some odd people use X-up... But it's not much of a difference once you figured the other problems
The usual way is to negate one of the axes, which transforms the handedness, but it introduces many more problems: Front-facing will become back-facing and vice versa. So all faces have to change their orientation... Moreover, rotations need even more changes, so if you want tp transform right-handed animations into left-handed systems, give the ms3d loader a check, I've gathered much information from various websites and hopefully made all the necessary changes there.
BTW: Some odd people use X-up... But it's not much of a difference once you figured the other problems