And you can turn off the display in a view: eye icon > Visibility Options > Components > Bezier Handles While Drawing Points/Knots.
gray
-----Original Message-----
From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM]On Behalf
Of Éric Cabot
Sent: Friday, October 07, 2005 10:26 AM
To: XSI(at)Softimage.COM
Subject: RE: XSI5 nurbs curves
Yes the first two CVs and last two CVs of an opened curve are the tangents of the curve at the beginning and the end. So the two blue lines that you see when you go in point mode are just a visual feedback that's all. If you use the old move point tool you will not see any change in behavior because of them. But if you use the new curve tweak tool you then have the ability to manipulate those tangents in many ways (rotating or scaling the tangent, aligning the tangent horizontally or vertically, etc.).
Eric
-----Original Message-----
From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM] On Behalf Of Joey Ponthieux
Posted At: Friday, October 07, 2005 9:49 AM
Posted To: xsi
Conversation: XSI5 nurbs curves
Subject: Re: XSI5 nurbs curves
Actually this makes perfect sense for a NURBS curve. While XSI 4.2 does not appear to show you these handles, at least I can't seem to make them appear, considering typical NURBS rules they are probably there but you just can't see them. They are likely hidden on top of the first and last CV's. By default a cubic NURBS(3) curve requires approximately 1 more CV than the define curve order IE a cubic 3 requires 4 CVs. So a cubic NURBS would require you to create at least 4 CVs in order to see the curve. Consider Soft 3D 3.9, it's B-Spline curve had something called phantom keys, which revealed handles just like you descibe by checking a command in it's Info>Selection page. It did not show these handles on teh NURBS curves but I suspect something was there. In Maya, these are typcally referred to as "Multiple End Knots". Maya's curve creation is a bit more revealing of the nature of a NURBS curve as it will not display a curve at all if you create a cubic curve with only 2 CVs!
. It requires a minimum of 4 CVs and Multiple End Knots to be on for the curve to be visible from 0 to 3, else anything less will only display a hull. If you turn Multiple End Knots off and create 4 CVs, it will only display a curve from CV1 to CV2 using the CV0 and CV3 as the curve's effective "end knots". As best I can tell you don't typically see this level of the curve construction in XSI. Further, XSI will allow you to create a NURBS curve with only two CVs, but if you look at XSI CV curve a bit closer after plotting just two CVs, by moving points using the M tool you will notice that it stacks 3 CVs on top of each other at the last point of creation. In other words, CV1, CV2, and CV3 are created simultanouesly where you click the last point, so even XSI is still required to conform to the rules of NURBS creation, Softimage is just making the creation method a little less complicated for the user by adding the extra points automatically instead of forcing the user to !
create them. Without having 5.0 up at the moment I would sugge!
st that
what Softimage has probably done is change the way that it reveals components of the NURBS curve to the user and that what you are seeing is more than likely a more sophisticated representation of what has always been there, but Soft chose not to display until now.
Joey Ponthieux
NCI Information Systems Inc.
NASA Langley Research Center
____________________________________________________________
Opinions stated here-in are strictly those of the author and do not represent the opinions of NASA or any other party.
Wayne Williams wrote:
>
> Odd, when I draw cubic by cv's or knot points then hit space bar to go
> into object mode...and then hit T to grab points on the curve...there
> are bezier handles on the beginning and end points. Not on any of the
> inbetween points though...just the beginning and end. This was not the
> behavior in any previous version was it? There seem to be workarounds to
> the issue that Dadi was facing so no biggie! :)
>
> -----Original Message-----
> From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM] On Behalf
> Of Sandy Sutherland
> Sent: Friday, October 07, 2005 2:48 AM
> To: XSI(at)Softimage.COM
> Subject: Re: XSI5 nurbs curves
>
> They do not - I just drew a curve by cvs - look just like it always
> did!!
>
> S.
>
> ----------------------------------------------------------
> Sandy Sutherland Digital Doodeller - TD
> The Refinery (Cape) http://www.refinery.co.za
> mailto:sandy(at)refinery.co.za
> (P) (+27 21) 480 3132 (F) (+27 21) 480 3101
> ----------------------------------------------------------
>
> ----- Original Message -----
> From: "Wayne Williams" <wayne(at)realtimegaming.com>
> To: <XSI(at)Softimage.COM>
> Sent: Thursday, October 06, 2005 7:18 PM
> Subject: RE: XSI5 nurbs curves
>
> > Hey Kris, they come with tangent handles now as well unfortunately. Im
>
> > with Dadi on this one...if it ain't broke...please don't do so.
> >
> > -----Original Message-----
> > From: owner-xsi(at)Softimage.COM [mailto:owner-xsi(at)Softimage.COM] On
> > Behalf Of Kris Rivel
> > Sent: Thursday, October 06, 2005 1:00 PM
> > To: XSI(at)Softimage.COM
> > Subject: Re: XSI5 nurbs curves
> >
> >
> >
> > "Create>Curve>Draw Cubic by CVs" will give you the traditional curve.
> >
> > Kris
> >
> > Dadi Einarsson wrote:
> >
> >> ....so what the hell has happened to curves in 5? I have a rig which
> >> depends on cluster contraints, said cluster contraints now being
> >> utterly useless as the new bezier handles move the tag point away
> >> from
> >
> >> its center. There's something very buggy happening between saving a
> >> scene and reopening it but basically what happens is that when I
> >> reopen my scene the beziers have gone berserk and scewed all the
> >> clusters away from their centers, thus completely exploding my rig.
> >> Softimage - something like bezier handles on curves seems like it
> >> could be a good idea, but at least leave regular curves that are
> >> proven to work and are a fundamental part of workflow as an option.
> >> Very upset.
> >>
> >
> >
> > ---
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