Spiro splines

human · Post by **human** » Fri Apr 03, 2009 9:36 pm

Sprio splines coming for Inkscape

http://screencasters.heathenx.org/wp-co ... ep067.html

http://andy.brisgeek.com/archives/92

EDIT: This is going to be big

heyvern · Post by **heyvern** » Fri Apr 03, 2009 10:49 pm

Looks great! Spiro is "similar" to what AS does... but more "smooth". It looks great but... it seems that it could be a "one trick pony". The smoothing looks very extreme. I should play with it though to be sure.

The problem as I see it is that the feature only works within Inkscape. You can't export "spiro paths" and maintain those curves to be used in another application. The same problem with Adobe Illustrator files imported into AS. Maybe though it has a way to "convert" spiro to bezier when exporting eps... don't know.

-vern

mkelley · Post by **mkelley** » Fri Apr 03, 2009 11:06 pm

Kind of like Inkscape "discovered" how Mike programs his curves. Doesn't seem like all that big a deal to me, but I guess the analogy would be if AS suddenly had Bezier curves -- I guess that would be "big", so I can see how adding a similar drawing feature to the way AS works might be big somewhere else.

I actually don't miss Bezier anymore -- kind of got used to drawing with "spiro" curves <g>.

human · Post by **human** » Sat Apr 04, 2009 12:36 am

If you do want to play with it, you'll need to find a daily build from the subversion system.

Ugh.

Too advanced for me. (Sounds like a job for Genete or mkelley.)

The feature will land in version 0.47.

=============================

PS Here are some more faces -- collect 'em all !!

Man, that was fun!

Genete · Post by **Genete** » Sat Apr 04, 2009 7:48 am

Spiro splines seems not to be the same than AS curves. In AS the curvature of end points is zero and Spiro in Inkscape doesn't. They are completely different.
-G

mkelley · Post by **mkelley** » Sat Apr 04, 2009 12:21 pm

I don't know about that -- all I know is I can duplicate the tutorial look very closely by doing the same steps in AS -- the curves seem to behave the same way as I move the points. If I can achieve the same look by doing much the same steps I guess I don't care about the math involved.

dm · Post by dm » Sat Apr 04, 2009 3:03 pm

Looks like vector/B- splines (NURBS). It's more complicated mathematically, but offers 'smoothness'. Spiro? why not call it what it is?

http://devworld.apple.com/dev/techsuppo ... eider.html

http://en.wikipedia.org/wiki/NURBS has nicer pictures.

The math involved in the 'curve' type has an effect on how it works with animation. Maya users can [probably] attest to that.

human · Post by **human** » Sun Apr 05, 2009 4:58 am

Guys, I think you are still having some problem with the idea that this is something we haven't seen before.

There are curves and then there are curves. To say they are all alike is like saying that all women are built alike (two eyes, two noses, etc) ...Hmmm. Guess I don't know enough women?

For some reason, the nickname "Spiro" has been tacked onto curves that were formerly called Cornu or Euler curves. In mathgeek, they call it a clothoid, as in: "Captain Kirk, we've been invaded by the Clothoids."

However, I, too, was wrong about the difficulty in access to this. Inkscape actually lets you download a runnable 0.47 development version. You'll need 7Zip to un7zip.

http://www.inkscape.org/download/?lang=en

. . . AND it is saved out to pure SVG, to answer your question.

heyvern · Post by **heyvern** » Mon Apr 06, 2009 12:31 am

Genete is right by the way. AS curves aren't like this at all. You tend to get slight "bumps" or "non smooth" curves in AS if you have too many points. I'm not really sure I would want 100% spiro when drawing. I don't think you would want all curves to be exactly the same like this. They are all perfectly round. I may be seeing it wrong or not understanding but it looks... odd to me. It looks very cool and would be great for doing logos and fonts... I just don't know how far I would want it to go. Everything could end up with that similar "spiro" look on all the curves.

It would absolutely satisfy my obsessive compulsive tendency for perfect round smooth curves without a lot of work.

human wrote:. . . AND it is saved out to pure SVG, to answer your question.

And it maintains the shape of the "spiro curves"? Cool! That is important. Not much use if you can't "get them out" of inkscape.

-vern

human · Post by **human** » Mon Apr 06, 2009 1:36 am

heyvern wrote: . . . AS curves aren't like this at all. You tend to get slight "bumps" or "non smooth" curves in AS if you have too many points. . . . -vern

heyvern wrote: . . . I don't think you would want all curves to be exactly the same like this. . . Everything could end up with that similar "spiro" look on all the curves. -vern

Dang, you're intuitive!

As a matter of fact, the Spiro curves act the same way as you described AS, depending upon the smoothing factor. If smoothing is low, the jitters of pencil drawing affect the curves so as to take the gracefulness out of it . . .

. . . and when you dial up smoothness, everything DOES "end up with that similar 'spiro' look on all the curves."

You really hit the nail on the head--these restrictions are a deal killer, unless some young guy invents a radical new character-design style within these strictures.

It's slightly beyond the scope of this thread, but I am now hanging up my experiments with animating SVG out of Inkscape.

Perhaps you can even guess why. SVG's shape morphing is not reliable enough in the best environment: the Opera browser. For an Internet browser, it's not the main event, not high priority.

SVG Path morphing in Java is even more fragile and I doubt if that situation is going to improve in the foreseeable future.

Firefox doesn't even support SVG path morphing yet, so we have no idea whether Mozilla will ever take it seriously.

I have to make up my mind now whether to commit to Anime Studio or TB Animate.

Post by **Víctor Paredes** » Mon Apr 06, 2009 1:51 am

human wrote:However, I, too, was wrong about the difficulty in access to this. Inkscape actually lets you download a runnable 0.47 development version. You'll need 7Zip to un7zip.

Human, I can't find the link to download the 0.47 version, can you post the exact link, please? (or an explanation, maybe I'm too blind or silly to see it).

human · Post by **human** » Mon Apr 06, 2009 3:03 am

selgin wrote:Human, I can't find the link to download the 0.47 version, can you post the exact link, please? (or an explanation, maybe I'm too blind or silly to see it).

No problemo, selgin.

On this page

http://www.inkscape.org/download/?lang=en

Just look for the links in Development versions:

==============================

Compiled Packages

If you don't want to compile the code yourself, use the nightly build for your system:

Windows:

* Mirrored Win32 Builds

Linux:

* Autopackage Builds — See Autopackage Site for directions
* ZeroInstall feed — see 0install.net for more information
* Gentoo Dependencies — make sure everything has been compiled by the same version of g++. C++ ABI changed between gcc 3.3 and 3.4
* Debian Dependencies — everything is available in the unstable apt repositories.

Mac OS X:

* Mac OS X packaged application (.dmg), named by date.

Post by **Víctor Paredes** » Mon Apr 06, 2009 4:02 am

Thank you, human. It was tricky. I have seen some new features of Inkscape and I'm thinking seriously in leave behind Corel Draw.

human · Post by **human** » Mon Apr 06, 2009 4:30 am

You can un-7-ZIP the development version (.47) in any local folder.

But if you want to use Inkscape seriously you will need the stable build .46 for serious work. It should come with a real installer, I think.

Get both versions . . .

heyvern · Post by **heyvern** » Mon Apr 06, 2009 11:45 am

You want to hear something really funny and coincidental?

Just about a week ago I was creating a 3D model in Animation Master of a "Victorian style" hand truck (those push carts with two wheels you use to move boxes and such). I had all of these intricate spirals and floral filigree metal designs in the hand truck... EXACTLY like the tutorial posted here for Spiro curves.

A:M has an AI import plugin. I drew all the spirals in AI and used them as extrude paths in animation master.... good grief... I would have LOVED to have had "Spiro" curves for that process. Getting perfectly round and smooth spirals in Adobe Illustrator for the filigree metal extrusions was a pain in the arse.

So yes I think Spiro has it's use but it still feels a tiny bit like a novelty. Something that would save a ton of time in the right situation but not something you would use all the time.

-vern