Intersection of a cone of light from point $p=(x,y,z)$ and $xy$-plane












1














I am working on a programming problem where I want to display a cone of light from a point $p=(x,y,z)$ lying in space to some direction.



For example, if $p=(0,0,1)$, and the light is facing straight down with angle of 90 degrees, the intersection at $xy$-plane would be a circle with radius $r = 1$ (circular cone).



The equation(s) that I am looking for should be parametrized in such way that I can input $x, y, z$ and the two angles (altitude, azimuth), and get the intersection as output.



Please, no straight answers, I want to work this out by myself ;-)










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  • Start with the standard equation of the cone $z = sqrt{x^2+y^2}$. Then use transformations (first rotations and then translations) to put the cone where you want. Finally set $z=0$ in the equation to see where it intersects the $x,y$-plane.
    – Nick
    Nov 18 at 15:34










  • Write the equation for the cone in 3D and than set z=0.
    – Moti
    Nov 18 at 16:22
















1














I am working on a programming problem where I want to display a cone of light from a point $p=(x,y,z)$ lying in space to some direction.



For example, if $p=(0,0,1)$, and the light is facing straight down with angle of 90 degrees, the intersection at $xy$-plane would be a circle with radius $r = 1$ (circular cone).



The equation(s) that I am looking for should be parametrized in such way that I can input $x, y, z$ and the two angles (altitude, azimuth), and get the intersection as output.



Please, no straight answers, I want to work this out by myself ;-)










share|cite|improve this question






















  • Start with the standard equation of the cone $z = sqrt{x^2+y^2}$. Then use transformations (first rotations and then translations) to put the cone where you want. Finally set $z=0$ in the equation to see where it intersects the $x,y$-plane.
    – Nick
    Nov 18 at 15:34










  • Write the equation for the cone in 3D and than set z=0.
    – Moti
    Nov 18 at 16:22














1












1








1







I am working on a programming problem where I want to display a cone of light from a point $p=(x,y,z)$ lying in space to some direction.



For example, if $p=(0,0,1)$, and the light is facing straight down with angle of 90 degrees, the intersection at $xy$-plane would be a circle with radius $r = 1$ (circular cone).



The equation(s) that I am looking for should be parametrized in such way that I can input $x, y, z$ and the two angles (altitude, azimuth), and get the intersection as output.



Please, no straight answers, I want to work this out by myself ;-)










share|cite|improve this question













I am working on a programming problem where I want to display a cone of light from a point $p=(x,y,z)$ lying in space to some direction.



For example, if $p=(0,0,1)$, and the light is facing straight down with angle of 90 degrees, the intersection at $xy$-plane would be a circle with radius $r = 1$ (circular cone).



The equation(s) that I am looking for should be parametrized in such way that I can input $x, y, z$ and the two angles (altitude, azimuth), and get the intersection as output.



Please, no straight answers, I want to work this out by myself ;-)







analytic-geometry






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share|cite|improve this question











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asked Nov 18 at 15:28









ZzZzZz

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  • Start with the standard equation of the cone $z = sqrt{x^2+y^2}$. Then use transformations (first rotations and then translations) to put the cone where you want. Finally set $z=0$ in the equation to see where it intersects the $x,y$-plane.
    – Nick
    Nov 18 at 15:34










  • Write the equation for the cone in 3D and than set z=0.
    – Moti
    Nov 18 at 16:22


















  • Start with the standard equation of the cone $z = sqrt{x^2+y^2}$. Then use transformations (first rotations and then translations) to put the cone where you want. Finally set $z=0$ in the equation to see where it intersects the $x,y$-plane.
    – Nick
    Nov 18 at 15:34










  • Write the equation for the cone in 3D and than set z=0.
    – Moti
    Nov 18 at 16:22
















Start with the standard equation of the cone $z = sqrt{x^2+y^2}$. Then use transformations (first rotations and then translations) to put the cone where you want. Finally set $z=0$ in the equation to see where it intersects the $x,y$-plane.
– Nick
Nov 18 at 15:34




Start with the standard equation of the cone $z = sqrt{x^2+y^2}$. Then use transformations (first rotations and then translations) to put the cone where you want. Finally set $z=0$ in the equation to see where it intersects the $x,y$-plane.
– Nick
Nov 18 at 15:34












Write the equation for the cone in 3D and than set z=0.
– Moti
Nov 18 at 16:22




Write the equation for the cone in 3D and than set z=0.
– Moti
Nov 18 at 16:22















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