t file** - ply file with just x,y,z locations. I got it from a 3d scanner. Here is how first few lines of file looks like - ply format ascii 1.0 comment VCGLIB generated element vertex 6183 property float x property float y property float z end_header -32.3271 -43.9859 11.5124 -32.0631 -43.983 11.4945 12.9266 -44.4913 28.2031 13.1701 -44.4918 28.2568 13.4138 -44.4892 28.2531 13.6581 -44.4834 28.1941 13.9012 -44.4851 28.2684 ... ... ... In case you need the data - please email me on **nisha.m234@gmail.com**. **Algorithm:** I am trying to find principal curvatures for extracting the ridges and valleys. The steps I am following is: 1. Take a point x 2. Find its k nearest neighbors. I used k from 3 to 20. 3. average the k nearest neighbors => gives (_x, _y, _z) 4. compute covariance matrix 5. Now I take eigen values and eigen vectors of this covariance matrix 6. I get u, v and n here from eigen vectors. u is a vector corresponding to largest eigen value v corresponding to 2nd largest n is 3rd smallest vector corresponding to smallest eigen value 7. Then for transforming the point(x,y,z) I compute matrix T T = [ui ] [u ] [x - _x] [vi ] = [v ] x [y - _y] [ni ] [n ] [z - _z] 8. for each i of the k nearest neighbors:<br> [ n1 ] [u1*u1 u1*v1 v1*v1] [ a ]<br> [ n2 ] = [u2*u2 u2*v2 v2*v2] [ b ] <br> [... ] [ ... ... ... ] [ c ] <br> [ nk ] [uk*uk uk*vk vk*vk]<br> Solve this for a, b and c with least squares 9. this equations will give me a,b,c 10. now I compute eigen values of matrix [a b b a ] 11. This will give me 2 eigen values. one is Kmin and another Kmax. **My Problem:** The output is no where close to finding the correct Ridges and Valleys. I am totally Stuck and frustrated. I am not sure where exactly I am getting it wrong. I think the normal's are not computed correctly. But I am not sure. I am very new to graphics programming and so this maths, normals, shaders go way above my head. Any help will be appreciated. **PLEASE PLEASE HELP!!** **Resources:** I am using Visual Studio 2010 + Eigen Library + ANN Library. **Other Options used** I tried using MeshLab. I used ball pivoting triangles remeshing in MeshLab and then applied the polkadot3d shader. If correctly identifies the ridges and valleys. But I am not able to code it. **My Function:** //the function outputs to ply file void getEigen() { int nPts; // actual number of data points ANNpointArray dataPts; // data points ANNpoint queryPt; // query point ANNidxArray nnIdx;// near neighbor indices ANNdistArray dists; // near neighbor distances ANNkd_tree* kdTree; // search structure //for k = 25 and esp = 2, seems to got few ridges queryPt = annAllocPt(dim); // allocate query point dataPts = annAllocPts(maxPts, dim); // allocate data points nnIdx = new ANNidx[k]; // allocate near neigh indices dists = new ANNdist[k]; // allocate near neighbor dists nPts = 0; // read data points ifstream dataStream; dataStream.open(inputFile, ios::in);// open data file dataIn = &dataStream; ifstream queryStream; queryStream.open("input/query.
pts", ios::in);// open data file queryIn = &queryStream; while (nPts < maxPts && readPt(*dataIn, dataPts[nPts])) nPts++; kdTree = new ANNkd_tree( // build search structure dataPts, // the data points nPts, // number of points dim); // dimension of space while (readPt(*queryIn, queryPt)) // read query points { kdTree->annkSearch( // search queryPt, // query point k, // number of near neighbors nnIdx, // nearest neighbors (returned) dists, // distance (returned) eps); // error bound double x = queryPt[0]; double y = queryPt[1]; double z = queryPt[2]; double _x = 0.0; double _y = 0.0; double _z = 0.0; #pragma region Compute covariance matrix for (int i = 0; i < k; i++) { _x += dataPts[nnIdx[i]][0]; _y += dataPts[nnIdx[i]][1]; _z += dataPts[nnIdx[i]][2]; } _x = _x/k; _y = _y/k; _z = _z/k; double A[3][3] = {0,0,0,0,0,0,0,0,0}; for (int i = 0; i < k; i++) { double X = dataPts[nnIdx[i]][0]; double Y = dataPts[nnIdx[i]][1]; double Z = dataPts[nnIdx[i]][2]; A[0][0] += (X-_x) * (X-_x); A[0][1] += (X-_x) * (Y-_y); A[0][2] += (X-_x) * (Z-_z); A[1][0] += (Y-_y) * (X-_x); A[1][1] += (Y-_y) * (Y-_y); A[1][2] += (Y-_y) * (Z-_z); A[2][0] += (Z-_z) * (X-_x); A[2][1] += (Z-_z) * (Y-_y); A[2][2] += (Z-_z) * (Z-_z); } MatrixXd C(3,3); C <<A[0][0]/k, A[0][1]/k, A[0][2]/k, A[1][0]/k, A[1][1]/k, A[1][2]/k, A[2][0]/k, A[2][1]/k, A[2][2]/k; #pragma endregion EigenSolver<MatrixXd> es(C); MatrixXd Eval = es.eigenvalues().real().asDiagonal(); MatrixXd Evec = es.eigenvectors().real(); MatrixXd u,v,n; double a = Eval.row(0).col(0).value(); double b = Eval.row(1).col(1).value(); double c = Eval.row(2).col(2).value(); #pragma region SET U V N if(a>b && a>c) { u = Evec.row(0); if(b>c) { v = Eval.row(1); n = Eval.row(2);} else { v = Eval.row(2); n = Eval.row(1);} } else if(b>a && b>c) { u = Evec.row(1); if(a>c) { v = Eval.row(0); n = Eval.row(2);} else { v = Eval.row(2); n = Eval.row(0);} } else { u = Eval.row(2); if(a>b) { v = Eval.row(0); n = Eval.row(1);} else { v = Eval.row(1); n = Eval.row(0);} } #pragma endregion MatrixXd O(3,3); O <<u, v, n; MatrixXd UV(k,3); VectorXd N(k,1); for( int i=0; i<k; i++) { double x = dataPts[nnIdx[i]][0];; double y = dataPts[nnIdx[i]][1];; double z = dataPts[nnIdx[i]][2];; MatrixXd X(3,1); X << x-_x, y-_y, z-_z; MatrixXd T = O * X; double ui = T.row(0).col(0).value(); double vi = T.row(1).col(0).value(); double ni = T.row(2).col(0).value(); UV.row(i) << ui * ui, ui * vi, vi * vi; N.row(i) << ni; } Vector3d S = UV.colPivHouseholderQr().solve(N); MatrixXd II(2,2); II << S.row(0).value(), S.row(1).value(), S.row(1).value(), S.row(2).value(); EigenSolver<MatrixXd> es2(II); MatrixXd Eval2 = es2.eigenvalues().real().asDiagonal(); MatrixXd Evec2 = es2.eigenvectors().real(); double kmin, kmax; if(Eval2.row(0).col(0).value() < Eval2.row(1).col(1).value()) { kmin = Eval2.row(0).col(0).value(); kmax = Eval2.row(1).col(1).value(); } else { kmax = Eval2.row(0).col(0).value(); kmin = Eval2.row(1).col(1).value(); } double thresh = 0.0020078; if (kmin < thresh && kmax > thresh ) cout << x << " " << y << " " << z << " " << 255 << " " << 0 << " " << 0 << endl; else cout << x << " " << y << " " << z << " " << 255 << " " << 255 << " " << 255 << endl; } delete [] nnIdx; delete [] dists; delete kdTree; annClose(); } Thanks, NISHA…
noceros 3D, en caso de aprobar satisfactoriamente el examen, se les otorga un reconocimiento avalado por el CMJ y la Secretaría del Trabajo. Este workshop va dirigido principalmente a estudiantes de arquitectura; sin embargo, ya que la parametrización es una herramienta que abarca diferentes ámbitos del diseño, se pueden integrar estudiantes de diseño industrial, artistas o estudiantes que tengan relación con lo gráfico y lo formal. Al finalizar el curso, los asistentes serán capaces de manejar Rhinoceros y Grasshopper en un nivel medio, con el objetivo de que el alumno pueda continuar aprendiendo con alguno de nuestros workshops subsiguientes o de manera autodidacta.
Las personas inscritas deben tener conocimientos básicos de geometría y de preferencia utilizar algún programa de dibujo en 2D o modelación en 3d. Rhino.GetMe Rigid // Enfocado a construir un objeto de diseño parametrizado a cualquier escala, el workshop se divide en tres módulos: Módulo 1 // Rhinoceros 3D // Una sesión de cinco horas. Módulo 2 //Grasshopper // Una sesión de cinco horas. Módulo 3 // Ejercicios prácticos /Tres sesiones de diez horas c/u. Es necesario traer el equipo necesario para trabajar, se cuenta con equipos en caso de que algún alumno no cuente con laptop pero son limitados, por favor avísanos a la brevedad si lo requieres. Se les recomienda que traigan dispositivos de almacenamiento en caso de que necesitemos compartir información.
El costo del Workshop es de $6500.00 para profesionales y $5000 pesos para estudiantes.
Pre-venta únicamente para estudiantes, hasta el día viernes 29 de junio, con un costo de $3500.00 pesos.
El cupo del evento es limitado puedes apartar tu lugar y terminar de liquidar antes del 29 de junio en pre-venta, antes del 6 de junio en admisión general.
Para hacer tu registro al workshop por favor envía un correo a workshop@transformalab.com incluyendo:
Nombre
Universidad u oficina de procedencia
Teléfono móvil
En el caso de estudiantes por favor incluyan una copia escaneada de su Constancia de Estudios para hacer válido su descuento.
Una vez recibida su información se les enviará un correo con la información necesaria para realizar su pago mediante depósito bancario, y posteriormente un mail de confirmación de su participación en el Workshop.
www.transformalab.com…
onstrates the following:
1. The definition's functionality employing HumanUI for the custom user interface.
2. The evaluation of the definition's ability to handle different point cloud data sets.
3. Video reports with the definition's results, animating subsequent per deviation step frames.
This definition calculates best fitting plane deviations. The number of manual set parameters has been minimized to two the facade per World UCS axis selection and the search width. This defines a box, which is used to crop protruding architectural details, which do not contribute to the analysis, but also ensures that large deformations are included in the calculation.
For the automation of the vertical and horizontal sections creation, the analyzed cloud is clustered, according to user defined number of 2d grid cells. The deviations corresponding to each cell are averaged in mean and median mode.
The process is displayed mostly in real time, with some speed up in some parts. Too long calculations have been omitted during video edit. The setup is responsive and benchmarks show that changing between dense point cloud data sets and facades is pretty quick (6.5-7.5M points, 25-45 deviation steps, 44x22 clusters), updates are calculated in acceptable timings (3-6 minutes).
I would like to thank Heumann A. and Zwierzycki M. who provided direct support with HumanUI and Volvox. Also Grasshopper3d forum users Maher S. and Segeren P., who contributed with Rhino viewport manipulation scripts.
More on Volvox:
http://papers.cumincad.org/cgi-bin/works/Show?_id=ecaade2016_171&sort=DEFAULT&search=ecaade%20volvox&hits=2629
http://www.food4rhino.com/app/volvox
http://duraark.eu/
HumanUI:
http://www.food4rhino.com/app/human-ui?page=1&ufh=&etx=…
ino Mc Neel, autore di "Architettura Parametrica - Introduzione a Grasshopper", il primo manuale su Grasshopper. I corsi PLUG IT nascono dalla volontà di promuovere le nuove tecnologie digitali di supporto alla progettazione e condividere il know-how maturato attraverso ricerca, collaborazione con i più importanti studi di architettura e pubblicazioni internazionali. Verranno introdotte le nozioni base di Grasshopper approfondendo le metodologie della progettazione parametrica e le tecniche di modellazione algoritmica per la generazione di forme complesse. Il corso è rivolto a studenti e professionisti con esperienza minima nella modellazione 3D e si articolerà in lezioni teoriche ed esercitazioni. Argomenti trattati: - Introduzione alla progettazione parametrica: teoria, esempi, casi studio - Grasshopper: concetti base, logica algoritmica, interfaccia grafica - Nozioni fondamentali: componenti, connessioni, data flow - Funzioni matematiche e logiche, serie, gestione dei dati - Analisi e definizione di curve e superfici - Definizione di griglie e pattern complessi - Trasformazioni geometriche, paneling - Attrattori, image sampler - Data tree: gestione di dati complessi - Digital fabrication: teoria ed esempi - Nesting: scomposizione di oggetti tridimensionali in sezioni piane per macchine CNC Verrà rilasciato un attestato finale. INFO E PRENOTAZIONI: http://www.arturotedeschi.com/wordpress/?p=2888…
merely automates finding clear intersections between pairs of objects and then splits the objects along those intersection *curves*, deletes the trims, then joins the remains, and cycles on. But within the confusing Rhino Settings tolerance value, wherever surfaces actually just sort of come closely together, there *is* *no* clear intersection curve. So it bugs out and stops working EVERY time you try more than a dozen or two spheres.
Some software can do this by switching to volumetric pixels (voxels). $9K-$30K Geomagic Freeform is an example of this. It also fails sometimes, often due to memory issues, as you can imagine since it needs to fill all inner space of each sphere definition with 3D pixels.
Materialize Magics for $16K can often handle such Booleans well. It will take a seeming lifetime to figure out such often pirate software kludges though.
One thing you can try though is to simply drape a mesh or NURBS plane onto the top of your spheres.
There's a well known *reason* your Booleans are failing. Nobody here has yet even hinted at it:
The main reason is that Rhino/Grasshopper developers don't care about the human element. The math exists to make this work very fast, every time. It just has to join things *right*, incorporating human knowledge of kissing surfaces, instead of acting stupidly, like some pocket calculator. But that would involve hacks that make 99% of complex Booleans work instead of 10%, and we can't have that since it will be SLOWER for the other 1% that just happen to have no nearly kissing or really kissing surfaces.
You could also use the new Cocoon plugin to do a surface *around* your structures, with a given radius of extension beyond the spheres, then offset that surface back the same radius. That is 100% robust, but won't offer quite as sharp of intersections, more rounded, like most everybody wants anyway.
You can *test* Boolean failures, by running a Grasshopper intersection command, to see the intersection curves, and zoom in to see how badly many of them are, all knotted, or twisted, or even with gaps, often with gaps.
It's a math problem nobody at McNeel wants to solve, sorry.
Just write a check for $25K and spend six months taking notes, like I did, and you can merge your simple spheres finally.…
Added by Nik Willmore at 6:33pm on October 20, 2015
up before you can produce a nice render. If you are using vray for Rhino you need to first learn how to set up (as an architect) a nice solar daylight system with environment, is actually very easy. (1 - set up sun lighting, 2 - set up environment, 3 - choose correct settings, such as activating indirect illumination)
However, since sketchup is the perfect draft tool for architectural design, it happens to have an environment with daylight defined already when you open an empty file. Vray for sketchup knows how to use all these settings so the only thing you need to do is to hit render. Apart from that you need to learn some simple material settings, which you find here: http://www.vray.com/vray_for_sketchup/manual/, the same manual for rhino here: http://www.vray.com/vray_for_rhino/manual/
The advantage of using vray for sketchup rather than for rhino (although if you can handle vray for one program its exactly the same for the other), is that you can easily import models from 3d warehouse. Sketchup is an excellent render set-up platform, except its only 32-bit so a to complex scene will simply not render. Rhino 64-bit will handle this better.
Conclusion, learn vray, whatever you learn can be applied to sketchup, rhino and 3ds max. Sketchup is probably a tool you already use and vray for sketchup will render with correct settings by default. Later when you take it to the next step you can go one and learn vray 2.0 for 3dsmax.
Personally I like using Luxology render engine that comes with Microstation, simply because I handle it better and Microstation is the best tool for architects in my opinion. However Vray is similar but more powerful.…
Added by Martin Hedin at 4:11pm on October 21, 2011
something in 3d, explode it to single surfaces, reference it to GH in proper order -manually- then unfold it with gh).
To make it really elegant you could try to make some "topology language" - have you seen this talk by Robert Lang http://www.ted.com/talks/lang/en/robert_lang_folds_way_new_origami.... ?
You can always make only few parametric types of structures - like leg, hand etc. (this is much easier than Mr.Lang's ) which can change its sizes, but topology stays the same.
Beside - Your sandwich looks really good, i played something similiar before.... have you tried thin PE (polyethylene) sheets ? Its similiar to PP (polypropylene) but a little bit softer. It is (PP) commonly used as tic tac box cap ( http://www.absolutelynarcissism.co/wp-content/uploads/2011/09/Tic-T... ) and some say that it can fold/unfold about 1000000 times. It would really simplify the whole production (just one cnc router needed to obtain full structure). Of course bending it will require prefabrication to look like e.g. http://www.grasshopper3d.com/video/the-swarm-2012 by Mr. Wieland Schmidt.
To clear things up :
1. It certainly can be done with rhino/gh
2. You should write some more on how should it all work (what you provide as geometry)
3. You should also provide some more info how 2d drawing looks now.
EDIT : I forgot about kinematics - use kangaroo. There are forces now like bending resistance etc.
…
other kind of planes because I need to deal with Display Pipline .
There's a few threads about similar problem( i'm posting them here as a reference)
1. Viewport rectangle
2. TextTag parallel to Viewport
3. Horster method (with timer)
4. Another horster method to get On screen display (also with timer)
5. Discussion how to send Rhino Viewport Cplane to GH
There is a lot of things possible to do using camera frustum plane such as:
- making custom project layout
- Camera-plane sections
- 3d Isovist (example of Francois)
- projections on the frustum plane
I need to output geometry to Grasshopper in order to use a Frustum Plane for dynamic operations like for example: On Screen Display of Text Tags with sections and other views.
…
3 arms and 6 legs (PS: Remember: in real-life our fee is proportional to the budget > thus > like Godzilla > the bigger the better).
In the mean time (auto detection of struts < min Allowed == true) get the gist of the whole "torque" issue, the other gist not to mention the other-other gist.
Of course you can opt for NOT making the cables (green) that stabilize the "extension" part of a given tensegrity strut ... yielding the Mother in Law syndrome (fat and ugly):
But ... hmm ... well ... are you really the chosen one? Here's your chance for the ticket to Paradise (full Lord's assistance, that is). Identify this engine, name the designer and the related immortal racer (when men were men).
Moral: Heaven can wait. …
ese explanations help (we will also look at your file) asap.
About your question regarding the Tutte graph drawing algorithm (also known as topological embedding):
The Tutte algorithm can be viewed as a special case of Spectral Graph Drawing, which is a mathematical solution for topological embedding formulated as an optimization problem. The formulation of the topological embedding (e.g. as in Tutte algorithm) is in fact quite similar to the so-called force-directed drawing that is often solved by heuristic methods like the one we have made for the SYNTACTIC plugin. You can read more about Force-Directed Graph Drawing (a.k.a. coin-graph drawing and kissing disks drawing) and Spectral Graph Drawing and Spectral Graph Theory in my dissertation.
The functionality of the Tutte algorithm is only guaranteed for graphs that are 3-connected, i.e. graphs with more than 3 vertices which cannot be torn apart unless at least two vertices are removed.
https://en.wikipedia.org/wiki/K-vertex-connected_graph
Speaking of the conditions for the Tutte algorithm to work properly: Practically, this implies, for instance, that there should not be rooms connected only to one other room.
Anyhow, long story short, we have decided to continue with Spectral Graph Drawing and 3D force-directed graph drawing. These algorithms are ready and with a couple of adjustments for maximum speed and stability we will release them shortly. Some conditions for these algorithms are easier to ensure, but in general if a node(room) is connected to only one space or the graph is not well connected one cannot expect a good graph drawing from neither of these methods. The other issue that is also common is that the force directed graph drawing will not work if one forces a big bubble to be squeezed in the middle of smaller bubbles. Stay tuned. …