Thanks very much for doing this. I look forward to testing it when I get back from holiday in a week.
I did get something that works, by stripping back the 'calculate envelope weights' compound to the core maths, but I'm keen to see anything else. Paul On 21 Jul 2013, at 04:03, David Barosin <[email protected]> wrote: > Hey Paul. Here's a scene that shows how to get a normalized weighted value. > It also shows how to use this weighted array on scale, rotation & color. It > uses a null group to influence particles. > > > On Wed, Jul 17, 2013 at 4:49 PM, Bk <[email protected]> wrote: > Thanks for all the replies. It's much appreciated. I'll grind through them > tomorrow at work. > > > > > On 17 Jul 2013, at 19:26, Vladimir Jankijevic <[email protected]> > wrote: > >> something we recorded last year while I was in NY: https://vimeo.com/44951318 >> maybe this helps :) >> >> Cheers >> Vladimir >> >> >> On Wed, Jul 17, 2013 at 2:05 PM, Vincent Ullmann >> <[email protected]> wrote: >> Quote Paul: >> >> { >> Ive managed to get barycentric interpolation working for a flat plane, >> and only 3 points, but I need it to accept multiple points in 3d space. >> } >> >> Not sure if this helps, but some time ago i made a ICE-Compound for >> calulating barycentric-Coordinates, based on 3 3D-Vectors. >> Dont know if my formula was correct.... ;-) >> >> >> Am 17.07.2013 19:47, schrieb Alok Gandhi: >>> You can have a look at my blog post: >>> http://alokgandhi.com/blog/2012/05/28/barycentric-coordinates-and-the-magic-of-locations/ >>> >>> >>> On Wed, Jul 17, 2013 at 12:58 PM, Ben Houston <[email protected]> wrote: >>> BTW here is our code for calculating barycoordinates from points and >>> creating points from barycoordinates: >>> >>> template<class T> >>> class Triangle3 { >>> public: >>> Vec3<T> a; >>> Vec3<T> b; >>> Vec3<T> c; >>> >>> Matrix44<T> getPointToBarycoordMatrix() const; >>> Matrix44<T> getBarycoordToPointMatrix() const; >>> }; >>> >>> template<class T> >>> inline Matrix44<T> Triangle3<T>::getPointToBarycoordMatrix() const { >>> M44x pointToBarycoordMatrix; >>> bool success = inverseSafe( pointToBarycoordMatrix, >>> getBarycoordToPointMatrix() ); >>> if( ! success ) { >>> T oneThird = ((T)1.0)/((T)3.0); >>> //Vec3<T> center = ( a + b + c ) * oneThird; >>> return Matrix44<T>( >>> 0, 0, 0, 0, >>> 0, 0, 0, 0, >>> 0, 0, 0, 0, >>> oneThird, oneThird, oneThird, 0); >>> } >>> return pointToBarycoordMatrix; >>> } >>> >>> template<class T> >>> inline Matrix44<T> Triangle3<T>::getBarycoordToPointMatrix() const { >>> Vec3<T> n = normal(); >>> return Matrix44<T>( >>> a[0], a[1], a[2], 1, >>> b[0], b[1], b[2], 1, >>> c[0], c[1], c[2], 1, >>> n[0], n[1], n[2], 0); >>> } >>> >>> And this you just multiple your point by the "pointToBarycoordMatrix" >>> matrix to get barycoords. And if you have barycoordinates, multiply >>> it by "getBarycoordToPointMatrix()" to get your point. >>> >>> We are using 4 coordinate barycoordinates where the fourth element is >>> the distance from the triangle plane in the normal direction. Just >>> set it to zero and you should be fine. The above can be converted to >>> Softimage Matrix types pretty easily. Probably could be added to the >>> Softimage SDK as well if it isn't already there. >>> >>> Best regards, >>> -ben >>> >>> >>> On Wed, Jul 17, 2013 at 12:04 PM, Ben Houston <[email protected]> wrote: >>> > So barycoords for a triangle works well and I believe there are tons >>> > of references on the web for this. Barycoordinates for polygons is a >>> > bit more problematic because they are no longer linear but rather >>> > polynomials and thus harder to calculate. I'd stick with triangles >>> > and then all those web references should work well. >>> > >>> > Is your problem calculating them from points? >>> > >>> > Basically this is a great guide: >>> > >>> > http://en.wikipedia.org/wiki/Barycentric_coordinate_system >>> > >>> > -ben >>> > >>> > >>> > On Wed, Jul 17, 2013 at 11:38 AM, <[email protected]> wrote: >>> >> Hi, I have spent days on this and I cant work it out >>> >> >>> >> I have a selection of points (not on a flat plane) and I have a test >>> >> position. >>> >> It returns an array that represents the weighting, related to the >>> >> proximity >>> >> to the other points. >>> >> >>> >> I want to have it so that when the test position is directly at a point, >>> >> the >>> >> value for that point in the array = 1 >>> >> and the rest will be zero >>> >> as the test point moves around the area it interpolates these values, but >>> >> they always add up to 1 >>> >> >>> >> It sounds really easy, but I’ve been literally* tearing my hair out over >>> >> this for days. >>> >> >>> >> Ive managed to get barycentric interpolation working for a flat plane, >>> >> and >>> >> only 3 points, but I need it to accept multiple points in 3d space. >>> >> >>> >> Please help. I’m going bonkers over this >>> >> >>> >> Paul >>> >> >>> >> *(not really literally) >>> > >>> > >>> > >>> > -- >>> > Best regards, >>> > Ben Houston >>> > Voice: 613-762-4113 Skype: ben.exocortex Twitter: @exocortexcom >>> > http://Exocortex.com - Passionate CG Software Professionals. >>> >>> >>> >>> -- >>> Best regards, >>> Ben Houston >>> Voice: 613-762-4113 Skype: ben.exocortex Twitter: @exocortexcom >>> http://Exocortex.com - Passionate CG Software Professionals. >>> >>> >>> >>> >>> -- >>> >> >> > > <weighted.zip>
