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Subject: 
LDraw coordinate system driving me crazy
Newsgroups: 
lugnet.cad.dev
Date: 
Sun, 19 Nov 2006 03:18:26 GMT
Viewed: 
2629 times
  
Hello all,

I'm having difficulties with the ldraw coordinate system. As fas I
understood it it's Right handed, just like OpenGL. So

X positive is right
X negative is left
Y Positive is top
Y Negative is bottom
z Positive is front
z negative is back

    Y

    /\
    |
    |
    ----> X
   /
|/_

Z

Please confirm this, I have been reading contradictions.

But let's assume this is correct, then why are all parts drawn upside
down while rendering in OpenGL?

It seems even MlCad is correcting for this by rotating 180 degrees
around the x axis, up becomes -Y and back Z

But why is this? It doesn't fix anything you still got one 'weird' axis
(in non professional people eye's) cuz you got the Y axis in the 'wrong'
way now instead of the Z-Axis.


Just wondering about this, while trying to determine how to orientate
stuff in my new animation software.

Greetings,

Roland



Message has 2 Replies:
  Re: LDraw coordinate system driving me crazy
 
(...) I've always understood it is: X positive is right X negative is left Y Positive is bottom Y Negative is top z Positive is back z negative is front In fact you can show this by adding a brick in MLCad and moving it around, watching how the X, Y (...) (17 years ago, 19-Nov-06, to lugnet.cad.dev)
  Re: LDraw coordinate system driving me crazy
 
(...) I've been having difficulty with importing/exporting .dat files from SketchUp. In SketchUp, if you stand at the Origin; X is right, Y is forward, and Z is up. The LDraw Primitives Reference ((URL)) says the LDraw axes are: X is right, Y is (...) (17 years ago, 19-Nov-06, to lugnet.cad.dev, FTX)

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