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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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but rather than keep everyone waiting, I've decided to share some as they become ready.
This also has the advantage that questions about components can be more easily grouped under the relevant post - so please do add any questions / comments / bugs / suggestions about these examples below.
So today I am posting some examples of the mesh utilities that come with the new release.
While these are not directly physics based, many of the forces and types of relaxation in Kangaroo are designed to work with meshes, and in the process of development I've ended up adding a number of simple utilities to make working with them a little easier.
I recommend also installing Weaverbird which has many more subdivision functions and other useful tools for working with meshes in Grasshopper. Also Plankton, Turtle, MeshEdit and Starling extend these possibilities still further.
Diagonalize
This component replaces every edge of a mesh with a new face. The new faces will always be quads, except for along the boundaries, where they will be triangles. It can be used to easily create diagrids. The input mesh can contain any mix of triangles and quads.
When treating the edges of a quad mesh as springs, diagonalizing it will often significantly change its physical behaviour. If you are trying to planarize a quad mesh, diagonalizing may sometimes allow you to stay closer to a target shape if it matches the curvature directions better.
diagonalize.gh
Checkerboard
This component assigns the faces of a mesh into a checkerboard pattern. The output is a list of 1s and 0s (which could represent black/white or true/false) which can be used to dispatch the faces into 2 lists, where no pair of adjacent faces have the same colour.
One nice application I found for this is applying alternating clockwise and counter-clockwise rotations as shown below. Also, on occasion you may want to planarize a quad mesh, but have some constraints on the shape and grid that prevent this, and triangulating only alternating quads to give a hybrid quad/tri mesh can sometimes be a good compromise, allowing a bit more freedom.
Note - Not all meshes can be assigned a checkerboard pattern!
As a simple example, take a mesh with 3 quads around one vertex - If we assign one black face, then both the neighbouring faces should be white, but then we have 2 white faces adjacent to one another, which violates the checkerboard condition.
Generally, we can say that if a mesh has any internal vertex with an odd number of faces around it, then we cannot apply a consistent checkerboard pattern to it (although not having any odd valence vertices is not in itself an absolute guarantee that a mesh is 'checkerboardable').
checkerboard.gh
WarpWeft
This sorts the edges of a quad mesh into 2 lists of line segments, which are like the warp and weft directions of a fabric. They can also be seen as a sort of mesh equivalent to the u and v isocurves on a NURBS surface.
This can be useful if you want to control the shape of a tension structure, because it allows you to assign different stiffnesses in the 2 directions.
As with the checkerboard component, not all meshes can be consistently assigned warp/weft directions. It follows a similar rule - all internal vertices should have an even number of adjacent faces. With a bit of care, it is usually possible to model the initial mesh in such a way as to allow this.
This component also has an output telling us whether or not each line is on a boundary of the mesh, as we will often want to treat these differently.
Same mesh relaxed with different warp/weft stiffness:
warpweft.gh
MeshCorners
This one is hopefully fairly self explanatory. In many simulations we want to anchor the corner points of a mesh. This saves us having to pick them manually in Rhino.
It works on quad meshes, and looks around the boundary vertices for any which do not have exactly 3 connected edges.
corners.gh
That's all for now. Coming soon - a "mesh tools 2" post explaining more of the components.…
main attention is set on easy to handle interface , which should be used at a early stage of conceptual design to respond to external and internal influences in a intelligent and sustainable way.
Participants will use the software Grasshopper as a parametric modeling plug-in for Rhino. The usage of this graphical algorithm editor tightly integrated with Rhino’s 3-D modeling tools open up the possibility to construct highly parametrical complex models. To generate this complexity we will use live linkages to several programs listed below:
• Autodesk Ecotect Analysis and Radiance via GECO
• Processing, Excel or Open Office via gHowl
• FEA software GSA via SSI
In this 3 intense days, the participants should learn the workflow of the plug-ins with the help of examples and get an overview of the different software’s, there possibilities for evaluating the performance of a design or the usage of additional tools to be not chained to a single system .
(e.g. parametrical accentuation, parametrical formation, parametrical reaction)
TIME AND LOCATION
27th – 29th September 2010Leopold-Franzens university innsbruck/austria
Technik Campus | ICT - building
Technikerstraße 21a
A - 6020 Innsbruck | Austria
47°15’50.71”N 11°20’43.45”E
detailed program as pdf-version
FOR WHOM
All levels are welcome (students & professionals)
The only requirement is knowledge of Rhino and Basic Grasshopper.
You will need a level which corresponds to the Grasshopper Primer course outline.
FEES
21 hours
professionals: 395€
students (bachelor/master): 250€.
REGISTRATION
please send a email to to.from.uto@gmail.com attached with following information :
Last Name
First Name
Date of Birth
Nationality
Email Address
Current Address
Profession or proof of student status
After submitting you will receive an email with a PayPal link to complete registration.…
ración de 150 horas divididas en cuatro módulos, arrancando el 22 de Marzo del 2011 y terminando la segunda semana de Junio con sesiones los Martes y Jueves de 18:00 a 22:00hrs y algunos Sábados de 10:00 a 14:00hrs.
El tema central del diplomado es el uso integral de la herramienta digital en el proceso de diseño a partir de la base teórica del fenómeno de la emergencia (entendida como la obtención de resultados complejos a partir de la interacción de elementos simples con reglas de bajo nivel de sofisticación).
El desarrollo del programa se concentra en la aplicación práctica de las reflexiones teóricas generadas mediante el uso de herramientas digitales generativas, principalmente Grasshopper (plug-in de modelado parametrico para Rhinoceros).
Contaremos con la presencia de dos colaboradores internacionales: EL primero será un miembro de LaN (Live Architecture Network) que impartirá un curso sobre programación avanzada en Grasshopper enfocandolo a la realización de un objeto construido, haciendo énfasis en la transición entre lo virtual, lo análogo y lo físico. El segundo es Jalal el Ali, maestro en arquitectura por la Architectural Association, líder de la Unidad de Geometría Generativa de Buro Happold y actual líder de proyecto en Zaha Hadid Architects, quien dará un curso intensivo enfocado al uso de la herramienta digital y la producción digital, enseñando procesos que ha aplicado en la empresa donde trabaja. Jalal pronunciará también una conferencia magistral.
Es un programa promueve el uso de nuevas tecnologías y la integración de procesos de producción desde la concepción del diseño, aplicando los conocimientos teóricos en un objeto físico usando el laboratorio de fabricación de la Universidad Iberoamericana.
…
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 :)…
we're actually using PET sheets for our flexures. We try to design so that the flexures don't go through more than +/- 30 degrees of deflection. If the angular deflection is kept small, the lifetime can definitely be on the order of 1000000 cycles.
As for the design process (item 2), ideally the designer would be able to use a simple 3D CAD tool to design a model of a robot, and the geometry would be represented by dimensioning the individual parts in the model. Maybe there should be some parametric primitive kinematic building blocks like four bar linkages, box frames, etc. that a user could build up a robot from. But, the key functionality the tool needs to provide is for the designer to be able to visualize how the robot will move when it's fabricated. This could mean observing (or plotting) the motion of a leg, a wing, or a series of body segments. Ideally, then, the tool would generate an unfolding of the design. How this would work is still very vague - maybe the user would assist in the unfolding, maybe there would be an optimization routine that computes optimal unfoldings based on criteria like minimal waste, or fewest pieces (I would *not* constrain the problem to construction from a single monolithic piece as in origami). The biggest problem we have right now, is that our design process is totally divorced from fabrication. Even if we went through the trouble of extruding individual thin plates in Solidworks and creating an assembly for visualizing the kinematics of a mechanism, that particular representation doesn't transfer easily to the fabrication process because it's essentially monolithic.
Item 3: The 2D drawing is simple a drawing done manually in Solidworks. There are different layers for flexure cuts, outline cuts, and potentially any cuts to be made in the plastic flexure layer. Depending on the robot, there may be many separate pieces for different parts and linkages in a single robot. For example, the drawing for a robot containing a fourbar linkage may have the linkage laid out as a physically separate piece consisting of five rigid links connected by four flexure hinges. During assembly, the designer would then fold up that linkage and insert it into the robot wherever it's supposed to go. If you're curious you can see some sample 2D drawings for older designs here: http://robotics.eecs.berkeley.edu/~ronf/Prototype/ under the "Example Structures" heading.
I noticed Kangaroo seems to be a popular choice for physical simulations. I don't really even need to include forces like bending resistance - I'm happy to allow the design tool to approximate flexures as pin joint-type hinges. Once the design is unfolded, the details of how to cut the flexures could be worked out in a post-processing step. I wouldn't expect the tool to be able to realistically simulate the bending of the hinges.
I'm going to have to dig a lot deeper into understanding Grasshopper and Kangaroo. I only just got started with Grasshopper today by following the folding plate tutorial on wa11ace.com.au today. …
round each gap is called a compact circle packing, and this isn't always possible to achieve exactly on every surface, but luckily for a sphere it is.
You can break the problem into 2 parts:
-The combinatorics, or connectivity, ie how many circles there are, and which is tangent to which. This is often represented as a mesh, where each vertex is the centre of a circle, and the edges link the centres of the circles which are tangent to each other.
-The sizes and centre positions. If you treat the combinatorics as fixed, you can then concentrate on optimizing the radii and locations of the circles to get them as close to tangent as possible.
I have done some work on solving these 2 parts simultaneously (see video here), and shared some scripts for this here.
Alternatively we can deal with them separately. For the combinatorics you could use something regular, based on subdivision (for a sphere you might want to start with an icosahedron). Alternatively you could use the remeshing tool I recently shared here. This can cover any surface with a mesh of almost equal edge lengths.
For the second part there is a force in Kangaroo which can optimize any triangulated mesh so that there is a packing of spheres centred on its vertices (and if the mesh is smooth, this sphere packing also leads to a circle packing). The file cp_mesh1 in the circle packing directory of the new collection of Kangaroo example files I recently posted shows this.
As for limiting to a small number of specified radii, this is still tricky, and impossible without compromising some of the other conditions. If you allow some variable gaps between the circles, you can replace each one with the closest from your set of radii. If you do not choose your radii in advance, but generate a packing with continuously varying radii then cluster them, it can give a better fit.
Alternatively you can give up the requirement that the packing to be compact and have good tangency, but some gaps with more than 3 sides.
Circle packing is a beautiful and surprisingly deep topic. I'd also recommend taking a look at the work of Ken Stephenson, Bobenko Hoffmann and Springborn, and Mathias Höbinger's thesis, which goes into more detail about triangular meshes with tangent incircles.
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l, you can find examples of parametric design using LB/HB, specifically the HB component pollinator workflows.
In these examples, a GH component (data recorder) is used to locally store either input parameters or output values of different model configurations and transmit them to pollinator. I can imagine, depending on how your facade is made parametric in GH, that you could save those input parameters (e.g. angle of surfaces or height of extrusion) and output variables for each iteration (e.g. annual shading).
This a search process through the design space. I do think that if you would set up the model as such, then it would be ok that the components in the PV workflow resetted after each iteration as the results would be saved. There is even a really good visualization platform Mostapha has shared to go along pollinator.
You can find examples of these workflows in the forum, simply search pollinator. I have one that I shared somewhere as well, although it was doing rudimentary things it would help.
This design space approach is a bit different than the optimization approach utilizing components like galapagos. It gives you an idea of the space of possible different desings and allows you to compare alternatives. Plus, it usually allows me to avoid all these issues of losing results between components in the workflo.
I also find it very handy and much more efficient than simply allowing a component optimize everything for me. However, it can ncrease almost exponantially (or is it geometrically, I am always bad at this) to the range and number of your input parameters. So, if each square on the wall has more than a couple of input values for a a few input parameters, I would expect this to take a long time. Thankfully, the components in the workflow will let you know exactly how many iterations.
If this method is interesting to you and you follow it I would suggest a few things to hasten the process like utilizing only the squared above and on the sides of the PV panel, since the others won't really affect shading, selecting just 2 or 3 characteristic angles for extrusions, and perhaps approximating energy production through annual shading numbers (since I imagine they have an almost linear relationship).
I do hope that I have understood what you want to do and the above information helps. I'm sure Djordje will give much better feedback on the specifics of the PV workflow. I will try and keep this page saved so that I can send over the example once I'm back at work mid of next week.
Good luck!
Kind regards,
Theodore.
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