erning how to do that on a sphere.
So I know already all the different approches of how to get a relaxed voronoi pattern on a free-form open surface, but still don't know how to obtain the same elegant effect on a sphere (or an ellipsoid closed surface, whatever), or how to relax the facet dome cells.
Andrew stated on his site that he used kangaroo for this project, so the Spore Lamp consists in my opinion either of a relaxed voronoi 3d diagram (b-rep, b-rep intersection) on a sphere the cells of which have been planarized later on, or more likely it is a sort of relaxed facet dome.
The trick is to:
1. obtain a nicely-balanced voronoish diagram (or facet dome cells) on a sphere
2. keep each cell/polyline planar (or force them with kangaroo to be planar) in order to move scale and loft them later on.
Here is what I have by now.(files: matsys spore lamp attempt)
That's the closest appearance that I got so far (simple move scale and loft of facet dome cells with the amount of transformations being proportional to the power of the initial cell area: bigger cell = bigger opening etc.) - with no relaxation of the diagram. But it's obviously not the same thing as the matsys design.
Here are some of my attempts of facet dome relaxation, but well, it's certainly still not the right approach, and most importantly I don't know how to keep or force the cells to be planar after the relaxation.
1. pulling vertices to a sphere - no anchor points. That obviously doesn't make sense at all, but the relaxation without anchor points gives at the beginning a pattern that is closer to what I am looking for. (files: relaxation 01)
2. pulling vertices to a sphere - two faces of the initial facet dome anchored (files: relaxation 02)
3. pulling vertices to the initial geometry (facet dome) no anchor points (files: relaxation 03)
The cell pattern of the lamp kinda looks like this:
You can find it here: http://www.grasshopper3d.com/forum/topics/kangaroo-0-095-releasedgroupUrl=kangaroo&x=1&groupId=2985220%3AGroup%3A120977&id=2985220%3ATopic%3A972434&page=2#comments
Done with Plankton (of course without the "gradient increase" appearance), but in fact not, I took a look at Daniel Parker's Plankton example files, and it's not quite the same thing. Also the cells aren't planar...
The last problem is that during the relaxation attempts that I did, the biggest initial cells became enormous, and it's not like that in the elegant project by Andrew Kudless, that I'd like to achieve.
So to sum up:
Goal no 1: Obtain an elegant voronoi /facet dome cell pattern on a sphere (or an ellipsoid surface, whatever).
Goal no 2: How to keep the cells planar in order to be able to loft them later, obtain those pyramidal forms, and assemble easily
Have you got any ideas? Or maybe there's a completely different approach to that?
Cheers, and thanks in advance…
mers considering extreme sports reject mainstream retailers and like to check out small stores rather of at chains plus malls. Several smaller retailers discuss trends in sports shoe sales. http://skateszone.com/
Though athletic shoes and sports stores and from doorways retailers have reported somewhat uptick in footwear sales due to the increase in extreme sports, the particular beneficiaries inside the trend are independent surf and skate niche stores.
Some West Coast surf and skate shops stated teenagers and even more youthful Generation Xers are not only rejecting traditional sports, but they're also shunning mainstream retailers and malls meant for smaller niche shops transporting hard-to-come-by brands.
Eddie Miyoshi, district manager at Atomic Garage, a 3-store chain situated in Gardena, Calif., stated the soaring recognition of skateboard footwear has boosted the retailer's total footwear business 20-thirty percent this year, rather of '95.
Skate footwear presently represent 80-90 % of Atomic Garage's shoe sales, while couple of years back, Dr. Martens and Timberland drove the retailer's footwear business.
Like many retailers, Miyoshi pointed to Airwalk since the trend's catalyst.
However, if Airwalk broadened its distribution to larger chains, which are frequently located in malls, only a few skate shoe customers adopted. Rather, many youthful males have switched for your skate shops for additional elusive brands like Etnies, Duffs, and Electricity Footwear by Circus. By refusing to market bigger retailers or sports stores, these brands are increasing their cachet among youthful consumers.
"Kids don't want stuff which have been within the shops,In . Miyoshi added.
Searching ahead, Miyoshi forecasted skate shoe sales will remain strong through spring '97 provided "the [hot] vendors don't auction other [non-particularly shop] retailers."
"Skaters and non-skaters are rebelling against mainstream retailers so on to surf and skate shops for many looks," echoed Mark Richards, co-online sources Val Surf, a 3-store chain situated in North Hollywood, Calif. Soaring sales of skate footwear have driven total footwear receipts up 25 percent this year rather of '95.
"The quantity of that increase might be connected while using exposure of maximum games? I am unsure. [Skate footwear] may also be actually the think about the moment,In . Richards acknowledged. And in relation to getting this right look, youthful customers can be very picky.
"Skateboard footwear is a huge category for people, but we're not able to own the brands, Etnies, Duffs, Electricity and Nice, simply because they won't sell us," stated Mark Anderson, buyer at Chick's Sports, a six-store chain in Covina, Calif. "We have people coming every single day requesting them." Consequently, skate footwear have consistently ongoing to obtain about 5 % of Chick's overall footwear business. http://skateszone.com/the-top-8-best-skateboards-for-beginners-reviews-2017/
Nonetheless, some outdoors, niche sports and sports retailers are noting the growing recognition and coverage of maximum sports will receive a modest impact on footwear sales. Trailrunning footwear and approach/outdoors crosstrainers will be the two groups benefiting the very best inside the recognition. Like the skate shoe business, some retailers realize that styling instead of function frequently drives sales of individuals footwear.
"At this time the merchandise is a lot more visual than function," stated Chet James, gm of Super Jock 'N Jill, Dallas, speaking about trailrunning footwear. Still, James noted the current hype over adventure sports helps draw more customer traffic. "The marketing campaigns and media help bring growing figures of people in, nonetheless they frequently occasions day an issue that increases results on their own account,Inch he conceded.
John Wilkinson, executive vp inside the 85-store chain Track 'N Trail, Eldorado Hillsides, Calif., stated the shop has "seen some activity in approach footwear," but he requested the amount of consumers depend in it commercially sport. And, instead of accelerating total footwear business, Wilkinson speculated elevated sales of approach footwear and trailrunners are gnawing away at traditional hiking shoe and boot volume.
But Dan Bazinet, president of Overland Exchanging, a 34-store chain situated in Westford, Mass., believes the company-new looks have breathed existence for the wilting hiking boot category. "[Approach-type footwear] don't represent the lion's participate the hiking market, nonetheless they have elevated the hiking business and provided us extra sales," Bazinet stated.
He designated Timberland's Treeline Series and Rockport's Leadville line as strong performers. Unsurprisingly, he noted the company-new looks are attractive to youthful consumer base than traditional hikers.
For that month of June, sales of men's hikers were up 49 percent at Overland, rather of June '95, while sales of women's hikers were up 17 % for that month. Bazinet also attributed elevated sales that shops walked inside the hiking business, departing that business for that specialists.
Some retailers draw a good example concerning the hiking boom of two yrs ago combined with the current extreme sport phenomenon. "Plenty of bigger chains will get a specific percent in the industry while [extreme] sports remain a fad because they are selling cost-point type gear," described Steven Carre, assistant hard goods buyer at Adventure 16, a six-store chain situated in Hillcrest.
"However individuals [true enthusiasts] will say `we need real gear' and may shown up at us. That will help us after a while. What Size Skateboard good for an 3 4 5 6 7 8 9 10 11 12 13 14 year old
…
ch has a vertex in each of the vertices of the polyline. But, when I try to create the mesh using the Mesh Brep component, I get a simplified mesh, where the extra vertices in the edges of the polyline have disappeared. I think it is easier to understand what I am trying to say with the following screenshots:
Polyline:
Mesh created with the rhino command:
Mesh created using grasshopper:
The last mesh has less faces, as the Mesh Brep component gets rid of the extra vertices that define the polyline.
Any suggestions?
Thanks,
Diego…
imeBinder.CSharpArgumentInfo.Create'
Is it possible to solve this issue?
using System;
using IronPython.Hosting;
using IronPython.Runtime;
using Microsoft.Scripting;
using Microsoft.Scripting.Hosting;
using Microsoft.CSharp;
namespace Bob.Meshes {
public class pythonFromCShapr {
ScriptEngine engine = Python.CreateEngine();
public pythonFromCShapr() {
}
public void something() {
dynamic scope = engine.CreateScope();
scope.Add = new Func<int, int, int>((x, y) => x + y);
Console.WriteLine( scope.Add(2, 3));
}
}
}…
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
…
ly has finally metamorphosed to have all known major bugs fixed and is ready to be used by a larger number of people in our community.
Butterfly is powered by OpenFOAM, which is a validated and open-source engine for Computational Fluid Dynamics (CFD). Primarily, Butterfly assists with exporting geometry and other input parameters from the CAD + scripting interface to the OpenFOAM engine. The Grasshopper plugin supports live results visualization that updates as the CFD simulation iterates. The Dynamo plugin supports results visualization once the analysis is over or paused.
For installation instructions and guidance on getting started, check out the Butterfly wiki page. There, you can find step-by-step installation directions and tutorial videos. There also 3 YouTube playlists for getting you started with installing OpenFOAM for Windows and using Butterfly for Grasshopper and Butterfly for Dynamo.
Similar to other ladybug tools, Butterfly uses an external validated engine (in this case, OpenFOAM) and you need to install it first to get the insect up-and-running. However, unlike Radiance and EnergyPlus, OpenFOAM doesn’t have a native installation for Windows and it requires Linux to run. Accordingly, the current version of “OpenFOAM for Windows” uses a technology called docker to run a Linux virtual machine on your system, inside which OpenFOAM operates. While this sounds complicated, the good news is that all of this setup has been packaged into the installer for “OpenFOAM for Windows.” So running this installer with all its defaults should give you everything you need.
The bad news is that the installation can fail if you don’t check your Windows system properly beforehand or don’t follow every step carefully afterwards. You will also need to run Rhino, Revit, and OpenFOAM as an administrator to ensure Butterfly works properly (by right-clicking each launcher for the program and selecting “Run As Administrator"). This said, if you follow the steps carefully, you should have no issues with the installation. You can find some of the issues that people faced during the alpha testing and the solutions to them here.
Butterfly is the first plugin that is fully developed based on the structure that I discussed before which consists of a core library and [+] libraries for specific software (in this case Grasshopper and Dynamo). We hope this structure to extend ladybug tools to more platforms by re-using the current code. We will provide a better documentation with more details on this matter in the near future but for now you can use the API for butterfly, butterfly_grasshopper and butterfly_dynamo for customizing or extending the current development.
Finally, having access to a powerful CFD engine from inside parametric/generative modeling environments is a great power and as Spider-Man or Uncle Ben once said:
“with great power comes great responsibility!”
We believe in learning by doing and we don’t expect you to be a CFD expert to get started with butterfly however we expect you to educate yourself along the way. If you have never used OpenFOAM before here is a great presentation to get started. We also highly recommend checking out the official OpenFOAM User Guide that goes through most of its functionality. Finally, we have also collected a number of other learning resources on this page that can be a good starting point.
We understand that you will have questions about the plugins which you can post to this forum or Dynamo discussion forum however CFD related issues and questions should be posted to CFD Online.
I like to thank everyone who have helped us with the development and testing during the last year or so, and special thank to Theodore who single-handedly educated me through the process of migrating to OpenFOAM and developing butterfly. Butterfly wasn’t possible without Theodore!
As always let us know about your comments and suggestions.
Happy flying the butterfly! Happy Spring!
…
ger work.
Be aware, this release breaks file-forwards compatibility. You will not be able to open gh and ghx files saved with 0.8.0050 on previous versions, though of course you should be able to open old files without problems. If this is not the case, please yell loudly.
If you're having trouble loading Grasshopper, note that you must have the latest Microsoft C++ Runtimes installed on your machine. They can be downloaded from the microsoft website.
The new release can be downloaded from the usual location.
Here's a list of changes, additions and fixes since 0.8.0013:
File format forwards compatibility has been broken. You will not be able to open files saved with 0.8.0050 on earlier versions.
This release contains many breaking changes and GHA libraries compiled for older version may not work anymore.
Grasshopper Binary files (*.gh) are now saved as compressed data.
Grasshopper Binary files (*.gh) are now the default format.
Support for ancient versions of the Text Panel (still called Post-It from back then) has been removed.
Support for ancient versions of the Path Mapper (still called Path Lexer from back then) has been removed.
Placeholders for ancient versions of the Graph Mapper have been removed.
Gradient input parameters now show state tag icons (Reversed, Flatten etc.).
Geometry Cache name changes are now updated on every key press.
Geometry Cache name changes can now be cancelled with Escape.
Geometry Cache name changes can now be undone.
Mesh|Mesh intersection component now uses a different algorithm. The old behaviour is still available from the component menu.
Warning and Error balloons are now drawn as part of a Canvas Widget and will no longer show up in the Hi-Res image export.
Galapagos now accepts multiple fitness values. The true fitness will be the average of the collection.
Galapagos wires are drawn much fainter when the Galapagos object is unselected.
Medium fast redraw mode in Galapagos now immediately redraws instead of at the end of each generation.
Redesigned all Grasshopper file format icons and added larger size icons for high-dpi explorer views.
Redesigned the Most Recently Used files menu, it should now display much quicker.
Compass widget has been rewritten in an attempt to increase display performance.
Added preferences section for Compass widget.
Added preferences section for Align widget.
Added preferences section for Default Preview colours.
Added preferences section for Document Preview colours.
Added preferences section for the Most Recently Used files menu.
The Area component now accepts Breps, Meshes and Planar Closed Curves.
The Area Centroid component now accepts Breps, Meshes and Planar Closed Curves.
The Volume component now accepts Breps and Meshes.
The Volume Centroid component now accepts Breps and Meshes.
Added Merge Faces component (Surface.Util panel).
Added a Mesh Smooth component (Mesh.Util panel).
Added a Curve Seam component (Curve.Util panel).
Added Interpolate Curve With Tangents component (Curve.Spline dropdown).
Added GrasshopperFolders command to open Settings, Components and UserObject folders without loading the core plugin.
The window that reports on certain Loading Errors now has a Copy button.
Added Simplify post-process filter to parameters (in addition to Reverse, Flatten and Graft).
Parameter post processes (Reverse, Flatten, Graft & Simplify) can now also be assigned to output parameters.
Version History window now has formatting (not happy with this, I'm working on something better).
The Process Info window is gone.
Main menu has been redesigned.
Canvas toolbar has been redesigned.
Canvas context menu has been replaced by a Radial Menu.
Canvas now has a radial menu which will pop up on Middle Mouse Button clicks.
It's possible to switch between Radial and Legacy menus in the Preferences (Interface.Canvas section).
'Save As Copy' feature has been replaced by 'Save Backup' which is a GUI-less save including date+time stamp.
Added a 'Show in Folder' item to the File menu.
AutoSave settings are no longer available from the File menu, you now need to use the Preferences.
Selection shifts now also modify the view so you can use Ctrl+Left and Ctrl+Right to navigate up and downstream.
Mesh Edge display can now be toggled with Ctrl+M.
Preview modes now have shortcuts (Ctrl+1 = no preview, Ctrl+2 = wireframe, Ctrl+3 = shaded).
Solution States now have a default name.
Data Viewer window now responds to all required events.
Data Viewer window can now handle input and output parameters as well.
Canvas Navigation pane can now be dragged using the icon in the upper left corner.
The Persistent Data Editor has been redesigned.
It's now possible to select multiple items in the Persistent Data Editor list and edit their properties.
It's now possible to drag multiple items at the same time in the Persistent Data Editor list.
Item addition to the Persistent Data Editor is much improved.
The Persistent Data Editor is now non-modal.
The Canvas would remain black upon maximizing the Rhino window, this is fixed.
Sliders would cause multiple updates under certain conditions, this is fixed.
Digit Scrollers would cause multiple updates under certain conditions, this is fixed.
Pipes were inside out. This is fixed.
The curve component would not adjust invalid nurbs degrees, this is fixed.
Curves referencing Brep edges failed to load, this is fixed.
Points referencing Brep edges failed to load, this is fixed.
Referenced dlls in the VB/C# components sometimes resulted in invalid imports statements, this is fixed.
Pasting geometry in Rhino would cause a recompute of the Grasshopper solution, this is fixed.
Importing a file into the Rhino document would cause a recompute of the Grasshopper solution, this is fixed.
Galapagos would trigger superfluous solutions, this is fixed.
Mesh Solid Difference had a wrong name and description, this is fixed.
Several menu items were not greyed out despite not being usable, this is fixed.
The position and size of the Grasshopper window failed to get stored on Rhino shutdown, this is fixed.
The Persistent Data Editor would crash on parameters that did not support data proxies, this is fixed.
I'll add some additional information regarding some of the new UI features in subsequent posts.
--
David Rutten
david@mcneel.com
Poprad, Slovakia…
lly it should not make much of a difference - random number generation is not affected, mutation also is not. crossover is a bit more tricky, I use Simulated Binary Crossover (SBX-20) which was introduced already in 1194:
Deb K., Agrawal R. B.: Simulated Binary Crossover for Continuous Search Space, inIITK/ME/SMD-94027, Convenor, Technical Reports, Indian Institue of Technology, Kanpur, India,November 1994
Abst ract. The success of binary-coded gene t ic algorithms (GA s) inproblems having discrete sear ch sp ace largely depends on the codingused to represent the prob lem variables and on the crossover ope ratorthat propagates buildin g blocks from pare nt strings to childrenst rings . In solving optimization problems having continuous searchspace, binary-co ded GAs discr et ize the search space by using a codingof the problem var iables in binary st rings. However , t he coding of realvaluedvari ables in finit e-length st rings causes a number of difficulties:inability to achieve arbit rary pr ecision in the obtained solution , fixedmapping of problem var iab les, inh eren t Hamming cliff problem associatedwit h binary coding, and processing of Holland 's schemata incont inuous search space. Although a number of real-coded GAs aredevelop ed to solve optimization problems having a cont inuous searchspace, the search powers of these crossover operators are not adequate .In t his paper , t he search power of a crossover operator is defined int erms of the probability of creating an arbitrary child solut ion froma given pair of parent solutions . Motivated by t he success of binarycodedGAs in discret e search space problems , we develop a real-codedcrossover (which we call the simulated binar y crossover , or SBX) operatorwhose search power is similar to that of the single-point crossoverused in binary-coded GAs . Simulation results on a number of realvaluedt est problems of varying difficulty and dimensionality suggestt hat the real-cod ed GAs with t he SBX operator ar e ab le to perform asgood or bet t er than binary-cod ed GAs wit h t he single-po int crossover.SBX is found to be particularly useful in problems having mult ip le optimalsolutions with a narrow global basin an d in prob lems where thelower and upper bo unds of the global optimum are not known a priori.Further , a simulation on a two-var iable blocked function showsthat the real-coded GA with SBX work s as suggested by Goldberg
and in most cases t he performance of real-coded GA with SBX is similarto that of binary GAs with a single-point crossover. Based onth ese encouraging results, this paper suggests a number of extensionsto the present study.
7. ConclusionsIn this paper, a real-coded crossover operator has been develop ed bas ed ont he search characte rist ics of a single-point crossover used in binary -codedGAs. In ord er to define the search power of a crossover operator, a spreadfactor has been introduced as the ratio of the absolute differences of thechildren points to that of the parent points. Thereaft er , the probabilityof creat ing a child point for two given parent points has been derived forthe single-point crossover. Motivat ed by the success of binary-coded GAsin problems wit h discrete sear ch space, a simul ated bin ary crossover (SBX)operator has been develop ed to solve problems having cont inuous searchspace. The SBX operator has search power similar to that of the single-po intcrossover.On a number of t est fun ctions, including De Jong's five te st fun ct ions, ithas been found that real-coded GAs with the SBX operator can overcome anumb er of difficult ies inherent with binary-coded GAs in solving cont inuoussearch space problems-Hamming cliff problem, arbitrary pr ecision problem,and fixed mapped coding problem. In the comparison of real-coded GAs wit ha SBX operator and binary-coded GAs with a single-point crossover ope rat or ,it has been observed that the performance of the former is better than thelatt er on continuous functions and the performance of the former is similarto the lat ter in solving discret e and difficult functions. In comparison withanother real-coded crossover operator (i.e. , BLX-0 .5) suggested elsewhere ,SBX performs better in difficult test functions. It has also been observedthat SBX is particularly useful in problems where the bounds of the optimum
point is not known a priori and wher e there are multi ple optima, of whichone is global.Real-coded GAs wit h t he SBX op erator have also been tried in solvinga two-variab le blocked function (the concept of blocked fun ctions was introducedin [10]). Blocked fun ct ions are difficult for real-coded GAs , becauselocal optimal points block t he progress of search to continue towards t heglobal optimal point . The simulat ion results on t he two-var iable blockedfunction have shown that in most occasions , the sea rch proceeds the way aspr edicted in [10]. Most importantly, it has been observed that the real-codedGAs wit h SBX work similar to that of t he binary-coded GAs wit h single-pointcrossover in overcoming t he barrier of the local peaks and converging to t heglobal bas in. However , it is premature to conclude whether real-coded GAswit h SBX op erator can overcome t he local barriers in higher-dimensionalblocked fun ct ions.These results are encour aging and suggest avenues for further research.Because the SBX ope rat or uses a probability distribut ion for choosing a childpo int , the real-coded GAs wit h SBX are one st ep ahead of the binary-codedGAs in te rms of ach ieving a convergence proof for GAs. With a direct probabilist ic relationship between children and parent points used in t his paper,cues from t he clas sical stochast ic optimization methods can be borrowed toachieve a convergence proof of GAs , or a much closer tie between the classicaloptimization methods and GAs is on t he horizon.
In short, according to the authors my SBX operator using real gene values is as good as older ones specially designed for discrete searches, and better in continuous searches. SBX as far as i know meanwhile is a standard general crossover operator.
But:
- there might be better ones out there i just havent seen yet. please tell me.
- besides tournament selection and mutation, crossover is just one part of the breeding pipeline. also there is the elite management for MOEA which is AT LEAST as important as the breeding itself.
- depending on the problem, there are almost always better specific ways of how to code the mutation and the crossover operators. but octopus is meant to keep it general for the moment - maybe there's a way for an interface to code those things yourself..!?
2) elite size = SPEA-2 archive size, yes. the rate depends on your convergence behaviour i would say. i usually start off with at least half the size of the population, but mostly the same size (as it is hard-coded in the new version, i just realize) is big enough.
4) the non-dominated front is always put into the archive first. if the archive size is exceeded, the least important individual (the significant strategy in SPEA-2) are truncated one by one until the size is reached. if it is smaller, the fittest dominated individuals are put into the elite. the latter happens in the beginning of the run, when the front wasn't discovered well yet.
3) yes it is. this is a custom implementation i figured out myself. however i'm close to have the HypE algorithm working in the new version, which natively has got the possibility to articulate perference relations on sets of solutions.
…
e chosen to dive into Grasshopper. I’m about 6 months in. If some of my comments are completely off, please take that to mean that a feature is too inaccessible to a newish user rather that it’s just missing, as I may have stated.
One of my primary pain points is this. Things that can be done in other programs are invariably easier in other programs. This is a big enough issue that I doubt there’s an easy solution that an armchair qb like myself can offer up.
The interface:
I’ve used a lot of 3D programs. I’ve never encountered one as difficult as grasshopper. What in other programs is a dialog box, is 8 or 10 components strung together in grasshopper. The wisdom for this I often hear among the grasshopper community is that this allows for parametric design. Yet PTC (Parametric Technology Corp.) has been doing parametric design software since 1985 and has a far cleaner and more intuitive interface. So does SolidWorks, Inventor, CATIA, NX, and a bunch of others.
In the early 2000's, when parametric design software was all the rage, McNeel stated quite strongly the Rhino would remain a direct modeler and would not become a parametric modeler. Trends come. Trends go. And the industry has been swinging back to direct modeling. So McNeel’s decision was probably ok. But I have to wonder if part of McNeel’s reluctance to incorporate some of the tried and proven ideas of other parametric packages doesn't have roots in their earlier declaration to not incorporate parametrics.
A Visual Programming Language:
I read a lot about the awesomeness and flexibility of Grasshopper being a visual programming language. Let’s be clear, this is DOS era speak. I believe GH should continue to have the ability to be extended and massaged with code, as most design programs do. But as long as this is front and center, GH will remain out of reach to the average designer.
Context sensitivity:
There is no reason a program in 2014 should allow me to make decisions that will not work. For example, if a component input is in all cases incompatible with another component's output, I shouldn't be able to connect them.
Sliders:
I hate sliders. I understand them, but I hate ‘em. I think they should be optional. Ya, I know I can r-click on the N of a component and set the integer. It’s a pain, and it gives no feedback. The “N” should turn into the number if set. AAAnd, sliders should be context sensitive. I like that the name of a slider changes when I plug it into something. But if I plug it into something that'll only accept a 1, a 2, or a 3, that slider should self set accordingly. I shouldn't be able to plug in a “50” and have everything after turn red.
Components:
Give components a little “+” or a drawer on the bottom or something that by clicking, opens the component into something akin to a dialog box. This should give access to all of the variables in the component. I shouldn't have to r-click on each thing on a component to do all of the settings.
And this item I’m guessing on. I’m not yet good enough at GH to know if this may have adverse effects. Reverse, Flatten, Graft, etc.; could these be context sensitive? Could some of these items disappear if they are contextually inappropriate or gray out if they're unlikely?
Tighter integration with Rhino:
I'm not entirely certain what this would look like. Currently my work flow entails baking, making a few Rhino edits, and reinserting into GH. I question the whole baking thing, btw. Why isn't it just live geometry? That’s how other parametric apps work. Maybe add more Rhino functionality to GH. GH has no 3D offset. I have to bake, offsetserf, and reinsert the geometry. I’m currently looking at the “Geometry Cache” and “Geometry Pipeline” components to see if they help. But I haven't been able to figure it out. Which leads me to:
Update all of the documentation:
I'm guessing this is an in process thing and you're working toward rolling GH from 0.9.00075 to 1.0. GH was being updated nearly weekly earlier this year. Then it suddenly stopped. If we're talking weeks before a full release, so be it. But if we're looking at something longer, a documentation update would help a lot. Geometry Cache and Geometry Pipeline’s help still read “This is the autogenerated help topic for this object. Developers: override the HtmlHelp_Source() function in the base class to provide custom help.” This does not help. And the Grasshopper Primer 2nd Ed. was written for GH 0.60007.
Grasshopper is fundamentally a 2D program:
I know you'll disagree completely, but I'm sticking to this. How else could an omission like offsetsurf happen? Pretty much every 3D program in existence has this. I’m sure I can probably figure out how to deconstruct the breps, join the curves, loft, trim, and so forth. But does writing an algorithm to do what all other 3D programs do with a dialog box seem reasonable? I'm sure if you go command by command you'll find a ton on such things.
If you look at the vast majority of things done in GH, you'll note that they're mostly either flat or a fundamentally 2D pattern on a warped surface.
I've been working on a part that is a 3D voronoi trimmed to a 3D model. I've been trying to turn the trimmed voronoi into legitimate geometry for over a month without success.
http://www.grasshopper3d.com/profiles/blogs/question-voronoi-3d-continued
I’ve researched it enough to have found many others have had the exact same problem and have not solved it. It’s really not that conceptually difficult. But GH lacks the tools.
Make screen organization easier:
I have a touch of OCD, and I like my GH layout to flow neatly. Allow input/output nodes to be re-ordered. This will allow a reduction in crossed wires. Make the wire positions a bit more editable. I sometimes use a geometry component as a wire anchor to clean things up. Being able to grab a wire and pull it out of the way would be kinda nice.
I think GH has some awesome abilities. I also think accessing those abilities could be significantly easier.
~p…