Vector Reorientation: overcoming the twist. (Message 1 to 3 of 3)
From: Greg M Johnson
Subject: Vector Reorientation: overcoming the twist.
Date: 30 Sep 2007 22:08:06
Message: <47005686@news.povray.org>
I know "we" solved this problem years ago, but I've forgotten the solution.
I have an object that I am reorienting from y to -y. At the .y=0
transition, there is a flip.
I see how Mike Williams did it in sweepmesh, but for practicality in my case
I would like a single transform. Is there no simple mathematical
transformation that allows this to happen without the flip?
From: Christian Froeschlin
Subject: Re: Vector Reorientation: overcoming the twist.
Date: 1 Oct 2007 05:52:21
Message: <4700c355$1@news.povray.org>
Greg M. Johnson wrote:
> I have an object that I am reorienting from y to -y. At the .y=0> transition, there is a flip. > > I see how Mike Williams did it in sweepmesh, but for practicality in my case> I would like a single transform. Is there no simple mathematical> transformation that allows this to happen without the flip?
I'm not sure what you mean by "reorienting from y to -y without flip".
A rotation by 180 degrees might be what you are looking for.
Christian Froeschlin <chr### [at] chrfrde> wrote:
> Greg M. Johnson wrote:>> > I have an object that I am reorienting from y to -y. At the .y=0> > transition, there is a flip.> >> > I see how Mike Williams did it in sweepmesh, but for practicality in my case> > I would like a single transform. Is there no simple mathematical> > transformation that allows this to happen without the flip?>> I'm not sure what you mean by "reorienting from y to -y without flip".> A rotation by 180 degrees might be what you are looking for.
Hmm, y to -y but no flip? Like scale y by -1 so it's reversed, and then
translate it back to the same position? You can always put
multiple/sequential transformations into a single transform{} variable.
Charles