What's Murmur's benefit over say, SHA1 or MD5?
On Wed, Aug 15, 2012 at 2:27 PM, Ben Houston <[email protected]> wrote: > The basis of hashing in Alembic is the murmur3 hash. I'd recommend it. > > http://en.wikipedia.org/wiki/MurmurHash > > -ben > > On Wed, Aug 15, 2012 at 2:19 PM, Nicolas Burtnyk <[email protected]> > wrote: > > I've used hashes of the geometry data itself (vertex and polygon data) to > > identify meshes, but this obviously doesn't work if you want the hash to > > remain stable between edits of the mesh. If you want to know if 2 meshes > > are identical with just different names though, it's extremely reliable > > assuming you have a good hash function. > > > > -Nicolas > > > > > > > > On Wed, Aug 15, 2012 at 10:49 AM, Alan Fregtman <[email protected] > > > > wrote: > >> > >> I know, but normal artists will extract geo and do other things that > would > >> destroy any metadata I could put on the object itself. > >> > >> > >> On Wed, Aug 15, 2012 at 1:42 PM, Matt Lind <[email protected]> > >> wrote: > >>> > >>> You’re describing Asset Management. > >>> > >>> > >>> > >>> A solution is to put metadata on each mesh (ie: custom property or > >>> userdata blob) with a unique ID and register the asset somewhere such > as in > >>> a database. If the mesh is renamed, it’s name will be irrelevant as > you’ll > >>> be tracking the ID in the custom property, not the mesh name. You can > >>> quickly find the custom properties via FindObjects(). You can resolve > >>> collisions of duplicates using the mesh name. > >>> > >>> > >>> > >>> Matt > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> > >>> From: [email protected] > >>> [mailto:[email protected]] On Behalf Of Alan > Fregtman > >>> Sent: Wednesday, August 15, 2012 8:28 AM > >>> To: XSI Mailing List > >>> Subject: Anyone ever tried generating a unique hash based on topology? > >>> > >>> > >>> > >>> Hey guys, > >>> > >>> > >>> > >>> I'm trying to keep track of a few thousand meshes which are being > renamed > >>> between stages/departments and I was thinking it might be worth a shot > to > >>> generate a hash based on topology so that I could track them better. > >>> > >>> > >>> > >>> Has anyone tried this already? I got pretty close hashing a string of > >>> component counts and bounding box values... In a section of 415 meshes > there > >>> were only 8 hash collisions. > >>> > >>> > >>> > >>> Any ideas what else I can consider to make the hashes more unique? Or > an > >>> alternate solution to tracking existing sets of meshes with same > topology > >>> but potentially inconsistent naming? > >>> > >>> > >>> > >>> Cheers, > >>> > >>> > >>> > >>> -- Alan > >>> > >>> > >> > >> > > > > > > -- > Best regards, > Ben Houston > Voice: 613-762-4113 Skype: ben.exocortex Twitter: @exocortexcom > http://Exocortex.com - Passionate CG Software Professionals. > >
