What exactly do you mean by degree difference?
Arc center point
Do you know the respective degrees of each of those points in the arc?
Lets supose you have 1/4 of a circle, and the arc is the 2 quadrant of the trignometric circle, the degrees of the points would be PI/2 and PI, and the difference would be PI/2.
Do you have that?
Lets supose you have 1/4 of a circle, and the arc is the 2 quadrant of the trignometric circle, the degrees of the points would be PI/2 and PI, and the difference would be PI/2.
Do you have that?
If you are just given two points on a plane, any point that is at the same distance from both points could be a center (these points form a line that is perpendicular to the segment between the two points and that cuts this segment in the middle). If you know the radius, that narrows it down to 2 points.
What data do you have, exactly? Is this a 2D or a 3D problem? Can you give us an example situation (with concrete numbers)?
What data do you have, exactly? Is this a 2D or a 3D problem? Can you give us an example situation (with concrete numbers)?
Author
All I have are two points on a plane, and the vectors with which to establish the coordinate system about that plane, and I need to somehow get another point on that plane that will represent the center point of a circle whose circumference passes through those two points.
Author
This is a 3d problem. Here are some points...
start point: X = 18.0000 Y = 0.0000 Z = 6.0000
end point: X = 16.6298 Y = 6.8883 Z = 12.0000
The following in this case would be the center point that would lie on the same plane as the above points.
center point: X = -82.9766 Y = -7.8989 Z = -0.8803
If we were to draw an arc from start to end point, while rotating about this center, then the distance from center to start and center to end would be equal, hence they would both be the radius of a circle.
I was wondering if there is an algorithmic way to find this point.
start point: X = 18.0000 Y = 0.0000 Z = 6.0000
end point: X = 16.6298 Y = 6.8883 Z = 12.0000
The following in this case would be the center point that would lie on the same plane as the above points.
center point: X = -82.9766 Y = -7.8989 Z = -0.8803
If we were to draw an arc from start to end point, while rotating about this center, then the distance from center to start and center to end would be equal, hence they would both be the radius of a circle.
I was wondering if there is an algorithmic way to find this point.
Quote:Original post by kelaklub
This is a 3d problem. Here are some points...
start point: X = 18.0000 Y = 0.0000 Z = 6.0000
end point: X = 16.6298 Y = 6.8883 Z = 12.0000
The following in this case would be the center point that would lie on the same plane as the above points.
center point: X = -82.9766 Y = -7.8989 Z = -0.8803
If we were to draw an arc from start to end point, while rotating about this center, then the distance from center to start and center to end would be equal, hence they would both be the radius of a circle.
I was wondering if there is an algorithmic way to find this point.
no, there is not, because any algorithm aimed at finding such a point could return any of the infinitly many points that statisfy your demands, making the change of it finding that specific point rather unlikely.
why not just pick the centre at infinity? ok your radius will be infinite, and your arc a straight line, but thats also a correct solution the way you state the problem.
i think youre forgetting something. that normal vector you mentioned: are you sure its not a tangent vector at one of the points? that would give us something to work with..
Author
I think that you guys have given alot to think about. I appreciate it. I'm gonna take another look at this problem and see if there is some given information that I may have tosed as irrelevant. Thanks for everything.
Quote:the distance from center to start and center to end would be equal, hence they would both be the radius of a circle.
Do you want a half circle??
if not you need a radius or you have infinite solutions.
Quote:Original post by robert_pQuote:the distance from center to start and center to end would be equal, hence they would both be the radius of a circle.
Do you want a half circle??
if not you need a radius or you have infinite solutions.
what is that supposed to mean?
This topic is closed to new replies.
Advertisement
Popular Topics
Advertisement
