RE: [Flashcoders] Calc max radius of a circle
>>'rotating around the x-axis' is a perfectly reasonable statement for a 3D >>object: rotate something in the x-y plane by 90 degrees about the x-axis and >>it will end up in the x-z plane. Rotating around the z-axis would keep it in >>the same plane. You can't rotate a 2-d object about an axis at all, only a >>point. Well, I guess we're just arguing semantics then. You're still taking about moving part of the object out of x-y space and into the "z" space, or as you put it in your words, the "x-z" plane. Jason Merrill | E-Learning Solutions | icfconsulting.com >>-Original Message- >>From: [EMAIL PROTECTED] [mailto:flashcoders- >>[EMAIL PROTECTED] On Behalf Of Danny Kodicek >>Sent: Wednesday, November 23, 2005 4:33 AM >>To: Flashcoders mailing list >>Subject: Re: [Flashcoders] Calc max radius of a circle >> >> >>>>The difficult part of the question is that the circle is really a 3D >>object >>>>ie it can be rotate about the x or y axis. >> >>> Do you mean rotate into the "z" axis? X and Y are still just 2-D >>spaces. >> >>'rotating around the x-axis' is a perfectly reasonable statement for a 3D >>object: rotate something in the x-y plane by 90 degrees about the x-axis and >>it will end up in the x-z plane. Rotating around the z-axis would keep it in >>the same plane. You can't rotate a 2-d object about an axis at all, only a >>point. >> >>Danny >> >>___ >>Flashcoders mailing list >>Flashcoders@chattyfig.figleaf.com >>http://chattyfig.figleaf.com/mailman/listinfo/flashcoders NOTICE: This message is for the designated recipient only and may contain privileged or confidential information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of this e-mail by you is prohibited. ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
Re: [Flashcoders] Calc max radius of a circle
The difficult part of the question is that the circle is really a 3D object ie it can be rotate about the x or y axis. Do you mean rotate into the "z" axis? X and Y are still just 2-D spaces. 'rotating around the x-axis' is a perfectly reasonable statement for a 3D object: rotate something in the x-y plane by 90 degrees about the x-axis and it will end up in the x-z plane. Rotating around the z-axis would keep it in the same plane. You can't rotate a 2-d object about an axis at all, only a point. Well, then, if you rotate a circle around the global x or y axis by 90 degrees (picture a coin standing on edge), the radius of the largest circle that would fit in a rectangular bounding box would be 1/2 the diagonal of that rectangle, or ((x^2 + y^2)^0.5)/2. ...because you can then rotate the circle around the global z axis until its local x-y plane is parallel to the diagonal of the rectangle. OP, is that what you were looking for? ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
Re: [Flashcoders] Calc max radius of a circle
The difficult part of the question is that the circle is really a 3D object ie it can be rotate about the x or y axis. Do you mean rotate into the "z" axis? X and Y are still just 2-D spaces. 'rotating around the x-axis' is a perfectly reasonable statement for a 3D object: rotate something in the x-y plane by 90 degrees about the x-axis and it will end up in the x-z plane. Rotating around the z-axis would keep it in the same plane. You can't rotate a 2-d object about an axis at all, only a point. Danny ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
RE: [Flashcoders] Calc max radius of a circle
>>The difficult part of the question is that the circle is really a 3D object >>ie it can be rotate about the x or y axis. Do you mean rotate into the "z" axis? X and Y are still just 2-D spaces. Jason Merrill | E-Learning Solutions | icfconsulting.com >>-Original Message- >>From: [EMAIL PROTECTED] [mailto:flashcoders- >>[EMAIL PROTECTED] On Behalf Of Robert Edgar >>Sent: Tuesday, November 22, 2005 1:15 PM >>To: 'Flashcoders mailing list' >>Subject: [Flashcoders] Calc max radius of a circle >> >>I am trying to calculate the max radius a circle can be and have it still >>fit in a bounding box. >> >>The difficult part of the question is that the circle is really a 3D object >>ie it can be rotate about the x or y axis. >> >>Ie imagine a plain circle drawn on the screen, now imagine your could >>"push" the top of it down till its was edge on, then the max radius would be >>half the width of the box. If pushed in on the left till it was edge on it >>woulde be half the height of the box. >> >>But how about all the other angles in between. >> >>So you have width/height of box, and x rotation and a y rotation, so what is >>the max radius.. >> >>Thanks >>Rob >> >> >> >>___ >>Flashcoders mailing list >>Flashcoders@chattyfig.figleaf.com >>http://chattyfig.figleaf.com/mailman/listinfo/flashcoders NOTICE: This message is for the designated recipient only and may contain privileged or confidential information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of this e-mail by you is prohibited. ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
Re: [Flashcoders] Calc max radius of a circle
The difficult part of the question is that the circle is really a 3D object ie it can be rotate about the x or y axis. A circle is a 2d object, do you mean a cylinder? The radius would always remain the same, 1/2 the shortest side of the box, or, if the box is aquare, call it 1/2 the width, it is the pespective that would change. ryanm ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
Re: [Flashcoders] Calc max radius of a circle
it will only affect the 'radius' measured along an axis perpendicular to the rotation axis..to calculate those values you can just take two points, one on each opposited edge of the circle, calculate where they are in 3d space then project them onto your viewing plane.. but are you also concerned about perspective? are you trying to draw a circle rotating in 3d space without going into 3d transformations? or something else? martin I am trying to calculate the max radius a circle can be and have it still fit in a bounding box. The difficult part of the question is that the circle is really a 3D object ie it can be rotate about the x or y axis. Ie imagine a plain circle drawn on the screen, now imagine your could "push" the top of it down till its was edge on, then the max radius would be half the width of the box. If pushed in on the left till it was edge on it woulde be half the height of the box. But how about all the other angles in between. So you have width/height of box, and x rotation and a y rotation, so what is the max radius.. Thanks Rob ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders -- want to know what i think? probably not http://relivethefuture.com/choronzon ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
RE: [Flashcoders] Calc max radius of a circle
The rotation doesn't affect the maximum radius. The maximum radius will be the smaller of width or height, divided by 2. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Robert Edgar Sent: Tuesday, November 22, 2005 1:15 PM To: 'Flashcoders mailing list' Subject: [Flashcoders] Calc max radius of a circle I am trying to calculate the max radius a circle can be and have it still fit in a bounding box. The difficult part of the question is that the circle is really a 3D object ie it can be rotate about the x or y axis. Ie imagine a plain circle drawn on the screen, now imagine your could "push" the top of it down till its was edge on, then the max radius would be half the width of the box. If pushed in on the left till it was edge on it woulde be half the height of the box. But how about all the other angles in between. So you have width/height of box, and x rotation and a y rotation, so what is the max radius.. Thanks Rob ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders ___ Flashcoders mailing list Flashcoders@chattyfig.figleaf.com http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
