I see. I think it's a pretty bad naming convention.. =)
v1.Normalize(); should normalize itself like "InPlace" does, and
nothing else is necessary. Since it's a method of the vector object,
it should be assumed that it reffers to itself. If you want a
normalized copy you could just do this:
v2 = v1;
v2.Normalize();
that's what my c++ vector classes look like anyway ;-) "Place" is
confusing, people are lead to believe it reffers to a coordnate, while
- as you say - vectors don't have them, they're just a direction. It
should at least be named "NormalizeSelf" or something along those
lines.
IMO =)
--
stockholm.postproduction | www.stopost.se
On 2/15/06, kim aldis <kim(at)cg-soup.com> wrote:
>
> A vector - it's a vector, not a normal, a normal is usually used to describe
> a vector perpendicular to something, usually a surface - is a direction only
> so it doesn't have a 'tail' position. Nor does it have a coordinate. it's an
> important distinction.
>
> How helpful the documentation is when it's so wonderfully literal ;-)
> Although to be fair, the difference between Normalize and Normalize in
> place, is just that, one normalizes in place, the other doesn't, it just
> needs a bit more detail.
>
> Given vectors v1 and v2:
>
> v1.Normalize( v2 ); // normalize v2 and place the result in v1
>
>
> v1.NormalizeInPlace(); // normalize v1 and place the result in v1.
>
>
> Normalize divides the 3 components of the vector by the vector length.
>
> l = sqrt( x*x + y*y + z*z );
>
> x /= l;
> y /= l;
> z /= l;
>
>
>
>
>
>
> ________________________________
> From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM] On Behalf Of
> guillaume laforge
> Sent: 15-February-2006 08:49
> To: XSI(at)Softimage.COM
> Subject: Re: Vector to rotation
>
>
> I guess normalize is a one unit length vector with the tail at 0,0,0 and
> normalize in place is a one unit length vector with the tail at the same
> coordinate than the non-normalized vector.
>
> Cheers
>
> Guillaume Laforge
>
>
>
> On 2/15/06, Arvid Björn <arvidbjorn(at)gmail.com> wrote:
> > Thanks, I had it sorted, but your function is indeed useful for other
> > things, thanks for sharing :-)
> >
> > Just a question though, what's the difference between Normalize and
> > NormalizeInPlace, the SDK doc offers this detailed description:
> >
> > ----8<-----------
> > Description
> >
> > Normalizes this vector in place.
> > --------->8------
> >
> > :-P
> >
> > --
> > stockholm.postproduction | www.stopost.se
> >
> >
> > On 2/15/06, Derek Jenson <derekjenson(at)hotmail.com> wrote:
> > > Here is a function I created for getting a rotation from 2 objects. Feel
> > > free to use it if you find it helpful.
> > >
> > > Pass a Direction Object, an Up Vector Object, and the pass strings for
> > > which axis you want to point at the Direction Object and which axis to
> point
> > > toward your Up Vector Object ("x", "y", or "z"). Negatives axis aren't
> > > considered, but you can add those if needed. The function returns an
> > > SIRotation object.
> > >
> > > function RotFromObj (dirObj, upObj, majorAxis, minorAxis)
> > > {
> > > var dirVec, upVec, crossVec;
> > > var m3, rot;
> > > var X, Y, Z;
> > >
> > > dirVec = XSIMath.CreateVector3();
> > > upVec = XSIMath.CreateVector3();
> > > crossVec = XSIMath.CreateVector3();
> > >
> > >
> dirObj.Kinematics.Global.Transform.GetTranslation(dirVec);
> > >
> upObj.Kinematics.Global.Transform.GetTranslation(upVec);
> > >
> > > dirVec.NormalizeInPlace();
> > > upVec.NormalizeInPlace ();
> > > crossVec.Cross(upVec, dirVec);
> > > crossVec.NormalizeInPlace();
> > > upVec.Cross(dirVec, crossVec);
> > > upVec.NormalizeInPlace();
> > >
> > > var X, Y, Z;
> > >
> > > switch(majorAxis + minorAxis)
> > > {
> > >
> > > case "xy":
> > > X = dirVec;
> > > Y = upVec;
> > > crossVec.NegateInPlace();
> > > Z = crossVec;
> > > break;
> > >
> > > case "xz":
> > > X = dirVec;
> > > Y = crossVec;
> > > Z = upVec;
> > > break;
> > >
> > > case "yx":
> > > X = upVec;
> > > Y = dirVec;
> > > Z = crossVec;
> > > break;
> > >
> > > case "yz":
> > > crossVec.NegateInPlace();
> > > X = crossVec;
> > > Y = dirVec;
> > > Z = upVec;
> > > break;
> > >
> > > case "zx":
> > > X = upVec;
> > > crossVec.NegateInPlace();
> > > Y = crossVec;
> > > Z = dirVec;
> > > break;
> > >
> > > case "zy":
> > > X = crossVec;
> > > Y = upVec;
> > > Z = dirVec;
> > > break;
> > >
> > > default:
> > > X = crossVec;
> > > Y = upVec;
> > > Z = dirVec;
> > > }
> > >
> > > m3 = XSIMath.CreateMatrix3();
> > >
> > > m3.Set(X.x, X.y, X.z,
> > > Y.x, Y.y, Y.z,
> > > Z.x, Z.y, Z.z);
> > >
> > > rot = XSIMath.CreateRotation();
> > > rot.SetFromMatrix3(m3);
> > >
> > > return(rot);
> > > }
> > >
> > >
> > > Hope this helps,
> > >
> > > Derek Jenson
> > >
> > >
> > >
> > >
> > >
> > >
> > > >From: Arvid Björn <arvidbjorn(at)gmail.com>
> > > >Reply-To: XSI(at)Softimage.COM
> > > >To: xsi(at)Softimage.COM
> > > >Subject: Vector to rotation
> > > >Date: Thu, 9 Feb 2006 12:06:50 +0100
> > > >
> > > >Hey,
> > > >
> > > >Are there any built-in methods for converting a 3-dimensional vector
> > > >to xyz-rotation angles in XSI?
> > > >
> > > >-a
> > > >
> > > >--
> > > >stockholm.postproduction | www.stopost.se
> > > >
> > > >---
> > > >Unsubscribe? Mail Majordomo(at)Softimage.COM with the following text in
> body:
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> > >
> > >
> > >
> > > ---
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> >
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