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1)
Hi Clemens I've analysed a plate structure using Karamba and wanted to do a convergence analysis on results computed as a function of the number of elements.
Now, when strictly looking at the result magnitudes of internal energy (IE) and maximum displacement (w_max), it's acceptable, that their relative deviations are very small. But I cannot explain the tendencies of their graphs. From what I know, FEM should always compute underestimated results when compared to analytical solutions. So I don't understand why both the IE and w_max seem to be decreasing for an increasing number of elements.
But my main concern is the behaviour of the peak moment, it seems to be simply hill climbing untill suddenly a singularity kicks in. I initially wanted to use the peak moment as a fitness value for optimisation, but with this behaviour, I don't think that would make sense. I've attached my GH file as well.
It would be much appreciated if you could enlighten me on these subjects. Cheers Daniel Andersen
2)
Hi Daniel,
I could not run your definition because I have not all the plug-ins installed that you use.
You are basically right that the displacement should increase with a finer mesh. However the result of the shell analysis also depends on the shape of the triangles (well formed vs. very distorted). In order to test this, I think it would be interesting to use a very simple example (e.g. rectangular plate with one column) where you can easily control mesh generation. Would you like to start a discussion on this in the karamba group at http://www.grasshopper3d.com/group/karamba?
It is not a good idea to use the bending moment at a singularity for optimization because the result will be heavily mesh dependent. Also real columns do have a certain diameter and modeling them as point supports introduces an error.
Best,
Clemens
3)
oh, and by the way!
Here's some relevant literature on handling peak moments: https://books.google.dk/books?id=-5TvNxnVMmgC&pg=PA219&lpg=PA219&dq=blaauwendraad+plates+and+fem&source=bl&ots=SdDcwnrSA1&sig=6HulPmKNIhqKx4_rGxitteMC4CU&hl=da&sa=X&ved=0CDEQ6AEwA2oVChMIg66k0LPaxgIVgY1yCh1KPAeY#v=onepage&q=chapter%2014&f=false (Blaauwendraad, J., 2010. Plates and FEM : Surprises and Pitfalls, see Chapter 14) It would be great if a feature dealing with peak moments could be incorporated in Karamba. In my work, I ended up exporting my models to Robot in order to verify the moment values. Best, Daniel
4)
Hi Daniel,
thank you for your reply and the link to Blaauwendraads excellent book!
At some point I hope to include material nonlinearity in Karamba which will help in dealing with stress singularities.
If you want you could open a discussion with a title like 'moment peaks in shells at point-supports'. Then we could copy and paste the text of our conversation into it.
Best,
Clemens
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make quad mesh usable with Kangaroo and with limited inputs parameters in order to simulate funicular structures like "Vaulted Willow" or "Pleated Inflation" from Marc Fornes and the Verymany.
Here is a first attempt script.
As inputs there are :
Lines_in, just lines, no duplicates, on XY plane could have Z values, but the algorithm works on a , on XY plane could have Z values, but the algorithm works on a flat representation.
Tolerance is used to glue lines when points are closer than tolerance
Width is the half width of the “roads” going through the network
Angle is the shape of the ends of the roads, 0° means flat end, 180° a totally rounded end
Deviation is the shift generating spikes or enabling to generate pleated geometry
N_u is the number of subdivision along the “roads”, image above with 3 subdivisions on the roads
N_u is the number of subdivision across the “roads”
Zbool if false everything is flat, if true the mesh is in 3d, best with angle = 180° or -180°
For the outputs there is the topology of the network (like Sandbox)
As outputs geometry are put on datatree, each branch represent a path on the road, above 3 paths, which are brep output.
Adding a diagonal there are now 4 paths so 4 branches
The mesh M goes with F which are fixed points, anchor in Kangaroo.
U and V are lines in datatree, there will be used as spring in Kangaroo, U above
This script could be used to draw sort of roads, like in here https://codequotidien.wordpress.com/2013/03/22/hemfunction/
But the primary purpose is to do that.
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t defined from the discussion of radiation exchange between urban surfaces and the sky in urban heat island research (See Oke's literature list below). It will be affected by the proportion of sky visible from a given calculation point on a surface (vertical or horizontal) as a result of the obstruction of urban geometry, but it is not entirely associated with the solid angle subtended by the visible sky patch/patches.
So, I think using "geometry way" to approximate Sky View Factor is not correct. Sky View Factor calculation shall be based on the first principle defining the concept: radiation exchange between urban surface and sky hemisphere:
(image extracted from Johnson, G. T., & Watson, 1984)
Therefore, I always refer to the following "theoretical" Sky View Factors calculated at the centre of an infinitely long street canyon with different Height-to-width ratios in Oke's original paper (1981) as the ultimate benchmark to validate different methods to calculate SVF:
So, I agree with Compagnon (2004) on the method he used to calculate SVF: a simple radiation (or illuminance) simulation using a uniform sky.
The following images are the results of the workflow I built in the procedural modeling software Houdini (using its python library) according to this principle by calling Radiance to do the simulation and calculation, and the SVF values calculated for different canyon H/W ratios (shown at the bottom of each image) are very close to the values shown in Oke's paper.
H/W=0.25, SVF=0.895
H/W=1, SVF=0.447
H/W=2, SVF=0.246
It seems that the Sky View Factor calculated from the viewAnalysis component in Ladybug is not aligned with Oke's result for a given H/W ration: (GH file attached)
According to the definition shown in this component, I assume the value calculated is the percentage of visible sky which is a geometric calculation (shooting evenly distributed rays from sensor point to the sky and calculate the ratio of rays not blocked by urban geometry?), i.e solid angle subtended by visible sky patches, and it is not aligned with the original radiation exchange definition of Sky View Factor.
I'd suggest to call this geometrically calculated ratio of visible sky "Sky Exposure Factor" which is "true" to its definition and way of calculation (see the paper on Sky Exposure Factor below) so as to avoid confusion with "The Sky View Factor based on radiation exchange" as discussed in urban climate literature.
Appreciate your comments and advice!
References:
SVF: definition based on first principle
Oke, T. R. (1981). Canyon geometry and the nocturnal urban heat island: comparison of scale model and field observations. Journal of Climatology, 1(3), 237-254.
Oke, T. R. (1987). Boundary layer climates (2nd ed.). London ; New York: Methuen.
Johnson, G. T., & Watson, I. D. (1984). The Determination of View-Factors in Urban Canyons. Journal of American Meteorological Society, 23, 329-335.
Watson, I. D., & Johnson, G. T. (1987). Graphical estimation of sky view-factors in urban environments. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 7(2), 193-197. doi: 10.1002/joc.3370070210
Papers on SVF calculation:
Brown, M. J., Grimmond, S., & Ratti, C. (2001). Comparison of Methodologies for Computing Sky View Factor in Urban Environments. Los Alamos, New Mexico, USA: Los Alamos National Laboratory.
SVF calculation based on first principle:
Compagnon, R. (2004). Solar and daylight availability in the urban fabric. Energy and Buildings, 36(4), 321-328.
paper on Sky Exposure Factor:
Zhang, J., Heng, C. K., Malone-Lee, L. C., Hii, D. J. C., Janssen, P., Leung, K. S., & Tan, B. K. (2012). Evaluating environmental implications of density: A comparative case study on the relationship between density, urban block typology and sky exposure. Automation in Construction, 22, 90-101. doi: 10.1016/j.autcon.2011.06.011
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diseño, construcción y entendimiento de nuestro entorno.
BIM está poniendo a disposición de los diseñadores y gestores auténticas bases de datos que pueden generarse, conectarse y editarse de forma paramétrica, proporcionando una sólida capa de realidad a los ejercicios de diseño generativo y computación que son objeto de estudio en Algomad, el seminario que busca popularizar la programación y la parametrización en el diseño y en la experiencia de nuestro entorno construido.
Tras un paréntesis en 2015, Algomad vuelve con el objetivo de demostrar cómo una visión computacional del BIM es una oportunidad para mejorar la forma de trabajar de ingenieros, arquitectos, constructoras y operadores de edificios e infraestructuras, tendiendo un puente entre las técnicas de diseño digital más avanzadas y la realidad de la construcción.
Algomad 2016 tendrá lugar en el centro de Madrid, en IE School of Architecture and Design, IE University, los días 3, 4 y 5 de Noviembre de 2016 y comprenderá 4 talleres así como ponencias a cargo de expertos de primer nivel.
Estructura de Algomad 2016
Algomad 2016 se estructura en torno a tres áreas temáticas principales:
BIM, como la metodología total específica para el sector de la construcción.
Computación, englobando las aplicaciones de programación y parametrización al diseño de edificios e infraestructuras.
Realidad, como marco de trabajo, buscando siempre resolver problemas reales a través de los dos puntos anteriores.
Público objetivo
Arquitectos, arquitectos técnicos, ingenieros y en general académicos, estudiantes de últimos cursos y profesionales del mundo inmobiliario y de la construcción que compartan un interés por la digitalización de nuestro sector. Se espera un nivel mínimo en el uso de herramientas BIM y de parametrización. Algomad proporcionará formación adicional y gratuita en las herramientas básicas a emplear en los talleres para asegurar un correcto desempeño.…
ively and creatively solve today’s product development challenges.
Our Rhino3D Foundations for Industrial Design class provides an in-depth look at 2D and 3D tools and methods with Rhino3D, a NURBs surface modeling software. In this class, we will systematically work through Rhino3D’s core features, using them to model the various components of a consumer product. Over the course of 3 days, we’ll cover some foundational topics, including Rhino interface and navigation, Rhino3D object types and properties, creating and editing 2D and 3D geometry, procedural modeling, automation, transforming geometry, Rhino modeling best practices, freeform vs. precision modeling, and exporting geometry.
You’ll take away the following:
Navigate the Rhino modeling environment
Create, edit, and modify curves, surfaces, and solids
Precision model using coordinate input and object snaps
Use transformation and universal deformation tools
Apply best practices for layer management and model annotation
Download the course one-pager. Need more information? Connect with us.
This class is ideal for:
Industrial designers who are new to Rhino3D and want to learn its concepts and technical features in an instructor-led environment.
For groups of 10 or more, contact Mode Lab at hello@modelab.is
Interested in additional training options?
https://www.modelab.is/upcoming-computational-design-events…
e think. Also, its easier to catch an error because the malicious component simply turns red/orange (in most cases). However, if you are adept at scripting, you are probably very used to recursive looping & conditional evaluation which you miss majorly in GH (it is possible in very limited ways through using series components or comparer components). So an adept scriptor may soon end up switching back to Rhinoscript unless they find the shift from VBscript to VB.net really fast & smooth (which is rare).
GH ofcourse has the advantage of keeping it all 'alive' and changing things with sliders/graphs/image painting, compared to Rhinoscript which is a run-once operation -- so that's where one makes a choice between recursive looping (in RS) & live interactivity (in GH). I'd say RS mostly wins the battle because interactivity is fancy, but recursion can be a necessity.
Now to VB.net. The one barrier I have hit most often with GH is speed. If you were working on a fairly large data set, or doing a number of surface/polysurface/brep operations, you hit the performance ceiling real fast, which is when the interactivity becomes almost useless -- because its nowhere close to real time anymore even if you had 12gb ram. Thus steps in VB.net (A bit of clever scripting can make a really significant difference).
Working a series of geometric operations in a code component is much faster than doing it through native GH components due to the fact that each native component comes with tonnes off error trapping code, preview generation (I think even if you turn it off, its still being computed, only not displayed), etc. while with VB, you can circumvent a lot of that.
If GH were to handle geometry even remotely comparable to what GC/Catia* can do, it would have a long way to go -- I am not sure if that is even the objective. For instance, I am currently working on a tower where all geometry is only meshes and polylines - no degree 3 curves, no surfaces/polysurfaces. This is because if the entire tower is to stay 'alive', Meshes are the lightest option with the amount of geometry being generated. And most of it is through code... there's only the sliders and a couple of other components that are GH native -- and its still in GH due to the interactivity. (I think there's a vast potential with Meshes that GH/Rhino are really not tapping into. There are all the building blocks, but no significant implementation. Giulio's weaverbird plugin is just a small example).
*GC/Catia cost significantly more than Rhino itself, and GH is a free plugin to Rhino. Morever, these softwares were written to be parametric modelling softwares from day1, unlike GH which is an add-on over the RhinoSDK, which was never developed from such a perspective. So a very very unfair comparison there, but GH is becoming so significant that its got a forum of its own -- gaining an almost 'independent software' status. I just hope the McNeel marketing people are not listening :)…
e display pipeline @ xx:xx:xx(xxxms)
iThe DrawViewportWires only when loaded!
The DrawViewportMeshes always when the viewport is refreshed!
Any Idea?
Public Overrides Sub DrawViewportWires(ByVal args As Grasshopper.Kernel.IGH_PreviewArgs) ' MyBase.DrawViewportWires(args)-> Disabled because nothing to Display If (Hidden) Then Return
For Each item As Rhino.Geometry.Circle In Circle args.Display.DrawCircle(item, GC, 3) Next
For Each item As Rhino.Display.Text3d In txt
args.Display.Draw3dText(item, GC) Next
End Sub
Public Overrides Sub DrawViewportMeshes(ByVal args As Grasshopper.Kernel.IGH_PreviewArgs) ' MyBase.DrawViewportMeshes(args) -> Disabled because nothing to Display If (Hidden) Then Return
Dim Brep As Rhino.Geometry.Brep Dim M As Rhino.Display.DisplayMaterial
For i As Integer = 0 To Circle.Count Brep = Rhino.Geometry.Brep.CreatePlanarBreps(Circle.Item(i).ToNurbsCurve())(0) M = New Rhino.Display.DisplayMaterial(VC.Item(Math.Min(i, VC.Count - 1))) args.Display.DrawBrepShaded(Brep, M) Next
End Sub
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serveral questions:the first thing is in c++ i have to implement more methods than in my c# test project.
they are:
int MyGhComponent::MasterParameterIndex::get(){ return 0;}void MyGhComponent::MasterParameterIndex::set(int index){ }bool MyGhComponent::IsValidMasterParameterIndex::get(){ return 1;}
i found no hint for the implementation of that interfaces. could someone tell me that is correct ?OK, it works, but is it well writen ? What is the MasterParameterIndex?
the second "bigger" problem is, i want to have an output of an pointlist.X y Z 1.2 1.3 1.12.1 5.2 9.2...
my first approch was to use a
void MyGhComponent::RegisterOutputParams(GH_Component::GH_OutputParamManager^ pManager){pManager->Register_PointParam("Coordinate", "XYZ", "Node-Coordinate");}
and
void MyGhComponent::SolveInstance(IGH_DataAccess^ DA){Collections::Generic::List<GH_IO::Types::GH_Point3D>^ pnt = gcnew Collections::Generic::List<GH_IO::Types::GH_Point3D>(); for (int i = 0; i < 10; i++) { GH_IO::Types::GH_Point3D^ point = gcnew GH_IO::Types::GH_Point3D(i, i, i); pnt->Add(i); } DA->SetDataList(3, pnt);}
but this exampel doesn't work...i wirte a small workaround and use the following
pManager->Register_DoubleParam("X-Koordinate", "X", "X"); pManager->Register_DoubleParam("Y-Koordinate", "Y", "Y"); pManager->Register_DoubleParam("Z-Koordinate", "Z", "Z"); Collections::Generic::List<double>^ pntx= gcnew Collections::Generic::List<double>(); Collections::Generic::List<double>^ pnty= gcnew Collections::Generic::List<double>(); Collections::Generic::List<double>^ pntz= gcnew Collections::Generic::List<double>(); ... add .. ect.
this workaround do the job, but i want a better soulution. and i know somewhere out there sould be a better solution. i want to use 3D Points directly in GH without list conversation.
so somebody a familiar with c++ / cli ? and could give me some tipps or a soulution ?
the first thing is: what is the right RegisterOutputParams ?
and witch data type is the right ? Point3d doesn't work. so i try GH_IO::Types::GH_Point3D and Rhino::Geometry::Point3d ...
br Friedrich…
rent actors to work together in real time on an architectural project.
DixieVR was born from the idea that virtual reality could become a fantastic tool for architecture and architects, not only for virtual tours but for the conception at its very core. Inspired by the efficiency of sandbox games, DixieVR will allow you to build a fully parametric 3D model from scratch in a very intuitive way and to simulate various factors like natural and artificial light, gravity, and more. DixieVR is also multi-user oriented : several people, architects or not, are able to work together in real time on the same 3D model and in the same shared immersive environment !
The project started in the Digital Knowledge department of Paris-Malaquais Architecture School.
The DixieVR Softwares can be found here : dixievr.github.io
// Interoperability
DixieVR deals with .dix files. For more information about this file format, please refer to the Interoperability documentation of DixieVR.
You can use this DixieIO plugin for Grasshopper/Rhinoceros for exchanging data between DixieVR (PC) & DixieViewer (Android).
You can import or export objects at any time inside a DixieVR scene. The Software also come with a library of premade objects that you might find useful. Adding your own premade objects to this library might be a good habit.
If you are hosting a scene, you also have the choice to open a .dix file directly from the main menu, this will load the last scene in which the geometry has been saved.
// Plugin
The DixieVR Plugin can be found in the Extra tab, come with 3 components and a example definition:
Dixie2Gh : Import DixieVR geometry to Grasshopper/Rhinoceros reading a .dix file (up to 1000 beams and/or 750 faces).
G2D_Polylines : Export Grasshopper/Rhinoceros Polylines to DixieVR writing a .dix file (up to 1000 line segments).
G2D_Mesh : Export Grasshopper/Rhinoceros Mesh to DixieVR writing a .dix file (up to 750 triangulated faces).
To install:
In Grasshopper, choose File > Special Folders > Components folder. Place the DixieIO_01.gha file there.
Right-click the file > Properties > make sure there is no "blocked" text.
Restart Rhinoceros or Unload Grasshopper.
// Contact - DixieVR
vr.dixie@gmail.com dixievr.github.io
- Oswald Pfeiffer oswaldpfeiffer.com
- Mathieu Venot mathieuvenot.com…
le and grasshopper timer to simplify simulation control. Double click the main Kangaroo component to open this remote. There are buttons for Stop(reset), Play, Pause, and Step (moves the simulation forward one iteration).
Line-line force - allows interaction between line segments - they are treated as rigid cylinders. As with springs, there are settings for offset and rest distance, so this can be used to simulate colliding rods, and also for keeping cylinders tangent to one another (can be used for reciprocal structures).
Gear simulator - collision between curves in a plane, can be used for various mechanical simulations - cams, gears, rack and pinions etc.
Developablize force - adjusts vertices of a mesh locally, to make angles around each interior vertex sum to 2*Pi, so the mesh can be unfolded to a flat sheet without stretching.
Volume dependent pressure force - allows you to set a rest volume for a mesh instead of just a fixed pressure. When combined with Laplacian smoothing for area minimization, this can be used to optimize for CMC (constant-mean-curvature) surfaces. It will also work on open meshes.
Translation lock - maintains a fixed relationship between a pair of points. This can be used to enforce periodic boundary conditions for TPMS.
Equalize angles force - given a set of angles (defined by 3 points each), this tries to adjust them all to become equal.
Mirror symmetry force - can be used to minimize curvature variation, and optimize for higher order curve continuity. It can also be used for simulating torsional resistance in curved rods.
True minimal surface relaxation - Laplacian smoothing force now includes an option for cotangent weighting, which optimizes for zero mean curvature, unlike spring based methods, or uniform weighted Laplacian smoothing which only roughly approximate this.
Fast sphere collide - allows much faster collision detection between large numbers of spheres. By placing these spheres at the vertices, this can also be used for collision between meshes.
Force-density element - an experimental one, more on this later
Projected-force - adjusts its strength so the component of the force in a given direction stays constant.
New mesh tools:
WarpWeft - sorts the edges of a quad mesh into warp and weft directions. This can be used to assign them different stiffness in fabric form-finding.
Checkerboard - sort the faces of a mesh into 2 lists so that 2 faces of the same colour are never adjacent.
MeshDirection - sorts the vertices of a quad mesh to give it a sort of u-v directionality
Refine Strips - subdivision in one direction only - can be used to generate developable strips
Stripper - separates out the strips of quads from a larger mesh
Unroller - unfolds a quad strip to flat without stretching
MeshMap - maps points from one mesh to another (can be used together with circle-packing to generate conformal mappings)
Reciprocal structure - generates starting geometry for a reciprocal structure from any input mesh (using the Plankton mesh library *Note* If you already have the Plankton components installed, you will need to update to version 0.3.0, which is available from here)
ReMesher - adjusts the connectivity of a mesh by flipping, splitting and collapsing edges to make all edge lengths closer to a target value
Diagonalize - creates a new face for every edge of the original mesh. Can be used on quad meshes to easily convert to a diagrid.
Refine - simple non-smoothing subdivision, splitting quads into 4 quads, and triangles into 4 triangles
QuadDivide - subdivide quads by any number squared, not just powers of 4
Corners - finds the corner vertices of a quad mesh
ByParent - simple quad subdivision, keeping the output grouped by parent face.
User objects:
The download comes with an increased collection of user objects to simplify setting up common simulation types - Including a simple to use origami simulator, a reciprocal structure generator, and a tool to generate compact circle packings from a CP mesh.
General:
Geometry input now accepts polylines and straight curves.
Hinges can now be fold completely flat in both directions.
Various other minor bug fixes and speed improvements (including much faster removeDuplicatePoints/Lines components)
*****
I've not yet updated all the documentation and example files to reflect this new version, but over time I will keep posting here with new demos and explanation of all these new features. I'll try and add a few new examples each week. Vote in the comments below if there is a feature mentioned above that you're particularly keen to hear more about soon.
No doubt there are still some bugs to be discovered. If something isn't working the way you expect or want it to, please post in this forum (ideally with a description or sketch of what you think should be happening, and a clear description of what happens instead and any error messages).
There are also some more new features that weren't quite ready to make it into this release, but are on the way shortly...
Kangaroo remains completely free, for personal, academic, and commercial use. I'm always interested to hear about projects done using it, and suggestions for improvements or additions.
Daniel
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