[Sidefx-houdini-list] image based fracturing

Michael K. O'Brien mobrien at pixar.com
Wed Apr 28 21:41:35 EDT 2010


Hola~

We ended up writing a medial axis SOP and the another one that did nearest
neighbor edge finding to solve this problem. In general the medial axis is the
most intuitive, but is also really slow. The nearest neighbor is really fast,
but gets a little dense as you try to keep the high frequency detail.

We played around with trace -> fuse and then re-adding high frequency detail.
It never was all that controllable. If your crack image has consistent
frequency detail in it, you can get some good looks with it, tho.

MO

>-- On Wed, Apr 28, 2010 at 06:26:50PM -0700, Andrew D Lyons wrote:
> You're right - my "off the top of my head" has issues.
> 
> The fuse SOP snap functionality helps with that a little - but there's
> still cleanup to do after that even. Anyone else got ideas?
> 
> Cheers
> 
> On 28 April 2010 22:00, Shaun Galinak <shaun at neonshaun.com> wrote:
> > With a trace sop, won't you always get those bordered edges?
> > Is there any way to get rid of those, so you have clean piece-against-piece
> > geometry?
> > I thought hole faces would take care of it, but it doesn't seem to help...
> >
> > -Shaun
> >
> > --------------------------------------------------
> > From: "Andrew D Lyons" <tstexture at gmail.com>
> > Sent: Wednesday, April 28, 2010 8:25 PM
> > To: <sidefx-houdini-list at sidefx.com>
> > Subject: Re: [Sidefx-houdini-list] image based fracturing
> >
> >> Well that's kinda what I'd call 2d - but nevermind. The trace SOP
> >> followed by an extrude, some point position noise and then a facet
> >> (unique points) could be your ticket....
> >>
> >> On 28 April 2010 16:25, Jim VanAllen <jimvanallen at gmail.com> wrote:
> >>> ideally 3-d, something extruded with a bit of noise to create interesting
> >>> edges.
> >>>
> >>> On Wed, Apr 28, 2010 at 4:22 PM, Andrew D Lyons <tstexture at gmail.com>
> >>> wrote:
> >>>> Is it a planar breakup or 3D?
> >>>>
> >>>> If it's planar (like broken glass) you might be able to use a Trace SOP?
> >>>>
> >>>> Cheers
> >>>>
> >>>>
> >>>> On 28 April 2010 16:19, Jim VanAllen <jimvanallen at gmail.com> wrote:
> >>>>> Hi,
> >>>>>
> >>>>> I'm trying to figure out the best way to take an image of some cracks
> >>>>> (like broken glass), and use it to break up a mesh in Houdini. I've
> >>>>> used some of the other techniques for fracturing a mesh, but we're
> >>>>> trying to figure out this specific problem, and my Houdini memory is
> >>>>> failing me at the moment.
> >>>>>
> >>>>> Any ideas?
> >>>>>
> >>>>> - jim
> >>>>> _______________________________________________
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> >>>>> Sidefx-houdini-list at sidefx.com
> >>>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >>>>>
> >>>>
> >>>>
> >>>>
> >>>> --
> >>>> =======================================
> >>>> Andrew D Lyons | Digital Artist | http://www.tstex.com
> >>>> =======================================
> >>>> _______________________________________________
> >>>> Sidefx-houdini-list mailing list
> >>>> Sidefx-houdini-list at sidefx.com
> >>>> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >>>>
> >>> _______________________________________________
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> >>>
> >>
> >>
> >>
> >> --
> >> =======================================
> >> Andrew D Lyons | Digital Artist | http://www.tstex.com
> >> =======================================
> >> _______________________________________________
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> >> Sidefx-houdini-list at sidefx.com
> >> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list
> >
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> >
> 
> 
> 
> -- 
> =======================================
> Andrew D Lyons | Digital Artist | http://www.tstex.com
> =======================================
> _______________________________________________
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> Sidefx-houdini-list at sidefx.com
> https://lists.sidefx.com:443/mailman/listinfo/sidefx-houdini-list

-- 
Michael O'Brien                                                       FX Lead
Pixar                                                       mobrien at pixar.com

Censorship is the mother of metaphor.
                            -Jorges Luis Borges



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