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I can't remember how to determine the new x y coordinates in a
circle and it's been a while since I've done any real math, so trying
to work the problem by myself has resulted in failure...
If I have a radius of 10(pov units)and the line is then rotated by
say 45degrees(or whatever angle I need), what is the new <x,y>?
I can't remember the formula for it...
I could just translate the object along x and then rotate around z,
but I kind of need the math to find it's new postion.
TIA
--
Phil
...coffee?...yes please! extra sugar,extra cream...Thank you.
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Phil Clute <pcl### [at] tiac net> wrote:
> I can't remember how to determine the new x y coordinates in a
> circle and it's been a while since I've done any real math, so trying
> to work the problem by myself has resulted in failure...
>
> If I have a radius of 10(pov units)and the line is then rotated by
> say 45degrees(or whatever angle I need), what is the new <x,y>?
> I can't remember the formula for it...
>
> I could just translate the object along x and then rotate around z,
> but I kind of need the math to find it's new postion.
#declare NewPos = Radius*<cos(radians(Angle)), sin(radians(Angle))>;
Note that at Angle=0 you get <Radius, 0>, while at Angle=90 you get <0,
Radius> (i.e. the rotation is anti-clockwise around the z-axis, starting at
the positive x-axis).
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I'm not sure to have well understood what's your problem in what you say,
but the polar coordinates of a point in a plane are
x = radius*cos(angle)
y = radius*sin(angle)
where angle is the angle beetwin the x-axis and the line from the origin and
your point, and radius, the distance from the origin to the origin
hoping it'll help you in any way
Baillp
3903B99A.B95AB357@tiac.net...
> I can't remember how to determine the new x y coordinates in a
> circle and it's been a while since I've done any real math, so trying
> to work the problem by myself has resulted in failure...
>
> If I have a radius of 10(pov units)and the line is then rotated by
> say 45degrees(or whatever angle I need), what is the new <x,y>?
> I can't remember the formula for it...
>
> I could just translate the object along x and then rotate around z,
> but I kind of need the math to find it's new postion.
>
> TIA
> --
> Phil
> ...coffee?...yes please! extra sugar,extra cream...Thank you.
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Thank you both.
--
Phil
...coffee?...yes please! extra sugar,extra cream...Thank you.
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In article <3903c0b1@news.povray.org>, "Chris Colefax"
<chr### [at] tagpovrayorg> wrote:
> #declare NewPos = Radius*<cos(radians(Angle)), sin(radians(Angle))>;
I would have done it this way:
#declare NewPos = vrotate(x*Radius, y*Angle);
--
Christopher James Huff - Personal e-mail: chr### [at] yahoocom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://chrishuff.dhs.org/
TAG Web page: http://tag.povray.org/
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Phil Clute wrote:
> I can't remember how to determine the new x y coordinates in a
> circle and it's been a while since I've done any real math, so trying
> to work the problem by myself has resulted in failure...
>
> If I have a radius of 10(pov units)and the line is then rotated by
> say 45degrees(or whatever angle I need), what is the new <x,y>?
> I can't remember the formula for it...
>
> I could just translate the object along x and then rotate around z,
> but I kind of need the math to find it's new postion.
Well, in "real" math, 0 degrees is along the positive x-axis and rotation
goes counterclockwise. That uses the formula <u,v>=radius*<cos theta, sin
theta>
But since POV is a lefty system :-) you (if rotating around y) start at
positive z and go clockwise in which case it's <u,v>=radius*<sin theta,
cos theta>
and remember these functions take radians...
this is exactly the kind of stuff we're doing in math right now (well,
actually we've moved on to periodic functions in general) and it's so
booooring and such a waste of my time and so pointless and boring and I
learn nothing from it and it's all review and it's review even if you
don't know trig since we're just using scalars to transform graphs and
well i shouldn't complain at least i can get it done in class while he
blabs on and on because next year will be worse i'll get actual homework
in that class
--
___ _______________________________________________
| \ |_ <dav### [at] faricynet> <ICQ 55354965>
|_/avid |ontaine http://www.faricy.net/~davidf/
"The only difference between me and a madman is that I'm not mad." -Dali
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In article <3904BE21.EAD45C53@faricy.net>, David Fontaine
<dav### [at] faricynet> wrote:
> this is exactly the kind of stuff we're doing in math right now (well,
> actually we've moved on to periodic functions in general) and it's so
> booooring and such a waste of my time and so pointless and boring and I
> learn nothing from it and it's all review and it's review even if you
> don't know trig since we're just using scalars to transform graphs and
> well i shouldn't complain at least i can get it done in class while he
> blabs on and on because next year will be worse i'll get actual homework
> in that class
You're lucky, I am stuck in Algebra II until next year, when I take
Trigonometry and Analytical Geometry.(Finally, something interesting! I
would rather have been doing Trig/Analytical Geometry *last* year...)
It looks like I won't even get Pre-Calculus until college. :-(
--
Christopher James Huff - Personal e-mail: chr### [at] yahoocom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://chrishuff.dhs.org/
TAG Web page: http://tag.povray.org/
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Chris Huff wrote:
> You're lucky, I am stuck in Algebra II until next year, when I take
> Trigonometry and Analytical Geometry.(Finally, something interesting! I
> would rather have been doing Trig/Analytical Geometry *last* year...)
> It looks like I won't even get Pre-Calculus until college. :-(
Damn! Sounds like a serious case of "disgruntled student feels cheated by
society and grows up to be the Unabomber." (No, no, j/k!!!!!)
--
___ _______________________________________________
| \ |_ <dav### [at] faricynet> <ICQ 55354965>
|_/avid |ontaine http://www.faricy.net/~davidf/
"The only difference between me and a madman is that I'm not mad." -Dali
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