Nah, not condescending at all. That definitely makes it more clear. Thanks again Alan!
On Wed, Jun 27, 2012 at 11:07 AM, Alan Fregtman <[email protected]>wrote: > Hey Chris, > > Here's an oversimplification, if it helps you or others visualize it > better: > > > 1. For every point on the source mesh, find the closest triangle our > target's mesh our point fits in -- a quad has 2 triangles, of course, so > one of them. > > 2. Imagine that triangle's edges are tightropes, and you start taking > a turn walking on each rope... you take steps and make your way to the > closest you can get to the point of interest while staying on that rope. > > 3. When you're the closest you can be, you mark it with a napkin where > you write the number of steps it took divided by a known number of steps it > takes to walk that rope. The result is your "weight" for that rope, or > edge. . Repeat for the other two "ropes". > > 4. Now you know that, let's say, your point of interest is 0.25 of > rope A, 0.7 of rope B and 0.15 of rope C. (0.25, 0.7, 0.15) are your > barycentric coordinates, more or less. > > 5. Now, if we want to know shapekey data (3d vectors per actual > vertex) from this arbitrary point in the target mesh triangle, how do we > compute it? Well, using those same weights from before we use > interpolation, which is just a fancy word for mixing up the values from > that triangle's vertices using each weight, and the result would be our new > shape vector. > > > Make more sense now? (I hope it didn't come off condescending; not my > intent.) > Cheers, > > -- Alan > > > On Tue, Jun 26, 2012 at 9:43 AM, Chris Covelli <[email protected]>wrote: > >> Thanks Alan, >> >> That link you provided is a bit over my head, but I get what you're >> saying. >> >> >> On Mon, Jun 25, 2012 at 3:42 PM, Alan Fregtman >> <[email protected]>wrote: >> >>> Well GATOR is not doing a 1:1 copy of the shapes, it's reinterpreting >>> every point by the transformation of each individual closest triangle using >>> pointlocator/locations magic, a.k.a. barycentric >>> coordinates<http://alokgandhi.com/blog/2012/05/28/barycentric-coordinates-and-the-magic-of-locations/> >>> sorcery math. >>> >>> Unless your meshes are completely and absolutely the same volume there >>> is always a chance of slight error, unfortunately. >>> >>> >>> On Mon, Jun 25, 2012 at 11:00 AM, Chris Covelli <[email protected]>wrote: >>> >>>> Hey Guys, >>>> >>>> Lets say I have a perfectly symmetrical mesh ( along the X axis ) and I >>>> build a few blendshapes for that mesh that are also perfectly symmetrical. >>>> >>>> Next, lets say I GATOR those blendshapes onto a different but also >>>> perfectly symmetrical mesh ( a lower/higher res version that has the same >>>> basic shape but different topology, for instance ). >>>> >>>> I've noticed that every time I do this the shapes on the new mesh end >>>> up being slightly asymmetrical. >>>> >>>> Anyone know why this happens? This is more of a curiosity rather than >>>> a problem I need fixed as I have a pretty quick method for getting the >>>> shapes symmetrical again without changing the topology. >>>> >>>> >>>> Thanks!! >>>> >>>> -Chris >>>> >>>> -- >>>> Chris Covelli >>>> http://kylevargas.net/ >>>> >>> >>> >> >> >> -- >> Chris Covelli >> http://kylevargas.net/ >> > > -- Chris Covelli http://kylevargas.net/
