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…
re are major changes and enhancements.
HONEYBEE
More Flexible Workflow - Many small modifications were made to support a more flexible workflow, such as the ability to separate a zone created with masses2Zones into editable HBSrfs that can be recombined. For the energy components, it is now possible to plug custom constructions directly into the components that set the zone constructions without writing them first into the library. For the daylighting components it is now possible to change all of the materials of specific surface types at once.
Support for Complex Geometry - Many small bugs for complex geometry have been fixed including the ability to import energy results correctly for curved NURBS surfaces as well as unconventional window configurations. Also, the intersectMasses component now almost always succeeds in splitting all of the surfaces of adjacent zones, no matter how complex the intersection is.
Automatic Download Issues Fixed - Many users who faced issues with not having “gendaymtx.exe” or who had trouble syncing with our github know that we faced an issue with automatic background downloads.
Air Walls - Honeybee EnergyPlus models now officially support air walls (or virtual partitions) in a basic implementation. Now, any time that you use the air wall construction or set a surface type to “air wall,” the air between adjacent zones will be automatically mixed. At present, this mixing is just a constant flow based on the surface area between zones connected by air walls multiplied by an adjustable “flow factor.” It is important to stress that this basic air mixing is not with the EnergyPlus Airflow Network, although the groundwork laid in this release will eventually allow for the implementation of the Airflow Network in future releases. As such, this present air mixing is only suitable for multi-zone conditions where there is not significant buoyancy-driven flow between zones.
Natural Ventilation - To go along with the new potential introduced by air walls, there has been a basic implementation of EnergyPlus’s natural ventilation objects in a new component called “Set EP Airflow”. The current setup allows for three possible types of natural ventilation: 1) natural ventilation through windows (with auto-calculated flow based on window area, outdoor wind speed/direction, and stack effects), 2) custom wind and stack objects that can be used to model things such as chimneys off of single zones, and 3) constant, fan-driven natural ventilation.
Additional Thermal Mass - The capability to add additional thermal mass to zones has been added. This is useful for factoring in the mass of indoor furniture or heavy interior objects such as chimneys.
New Utility Components - Abraham has added a couple of useful components to help calculate lighting loads based on bulb types and target lighting levels as well as a converter from ACH to the m3/s-m2 that the other HB components accept. Along this vein, there is also a component for adding in the resistance of Air Films to HB constructions.
Improved and Editable Ideal Air Loads System - The EnergyPlus Ideal Air System now goes through an automatic sizing period at the start of the simulation based on the extreme weeks of the weather file. Furthermore, the ability to adjust many of the parameters of the ideal air loads system have been added with a new “Set Ideal Air Loads Parameters” component. The component allows you to add in heat recovery, air side economizers and demand-controlled ventilation.
OpenStudio Export Update - The OpenStudio workflow is still largely under development but this release includes a version with a working VAV and PTHP system template for those curious with experimenting. Note that not all of the new features available for the basic “Run Energy Simulation” component are available for the OpenStudio component (such as air walls, natural ventilation, or additional thermal mass).
Microclimate/Indoor Comfort Maps - Blossoming from initial experiments with the radiant temperature map, a workflow for looking into sub-zone microclimate and indoor comfort has been initiated. All components for this are presently under the Honeybee WIP tab but, over the next month, they will be completing their development phase and moving into the rest of the tabs. If you are interested in testing when they are ready, please let Chris know. For a teaser video of the intended capabilities, see this video: (https://www.youtube.com/watch?v=fNylb42FPIc&list=UUc6HWbF4UtdKdjbZ2tvwiCQ)
LADYBUG
Monthly Bar Chart - After much demand from multiple parties, a new component to create monthly bar and line charts has been added. The component is particularly useful for plotting the outputs of the “Average Data” component like monthly EPW data or averaged monthly-per hour data. It also supports daily data and any type of Energy simulation results.
Wind Profile - To go along with the new capabilities of natural ventilation in Honeybee, Ladybug now has a fully fleshed-out Wind Profile component that allows you to visualize how wind speed changes with height in relation to your building geometry. The component is geared to understanding the conditions of prevailing wind and will be useful in the future for setting up CFD models. Credit goes to Djordje Spasic for adding in all of the new capabilities. In a similar vein, the appearance of the wind rose has also been improved thanks to suggestions from Alejandra Menchaca.
Faster Solar Adjusted Temperature - Thanks to the SolarCal method from the Center for the Built Environment at UC Berkeley (http://escholarship.org/uc/item/89m1h2dg), the solar adjusted temperature component now includes an option for a much faster calculation that produces results that are very close to those originally obtained with the genCumSky component. Instead of using the cumulative sky, the component can now accept the direct and diffuse radiation from the ImportEPW component. Over a whole year, this essentially takes a calculation that used to be a half-hour and shrinks it down to 10 seconds. Thanks again to those at UC Berkeley for keeping their work open source!
Instructions - Last but not the least, [It took me almost two years to understand this but finally] we have a text file that describes the installation step by step and is way easier to modify than a video. You can find it in the zip file. Credit goes to Chris!
We also want to welcome Anton, Patrick and Sandeep to the team. Anton has kicked off his development by working on a component to import and visualize epw ground temperature data and he will be continuing to develop components to bring in reliable precipitation data to Ladybug. With this basis, he will continue to implement Honeybee components for ground heat storage, earth tubes, rain collection and hot water systems. Patrick and Sandeep are working on integration of Honeybee to Energy Performance Calculator.
As always let us know your comments and suggestions.
Enjoy!…
les automatically at the right angle to form the cap of an icosahedron.
To complete the full icosahedron, we consider just the six points we already know, the five pentagon vertices and the raised pyramid tip and reorient one of the vertices using three-point transformation so it obtains the exact same relationship between vertices only one more stage beyond our little cap pyramid, and we do a five-fold polar array:
I used a password-protected cluster I ran into one the forum somewhere to reproduce Rhino's 3-point orient command:
A final 3-point orientation transforms in space the original pyramid tip down to the bottom:
Now we can create a convex hull which gives an icosahedron mesh:
So that's how you build an icosahedron in Rhino from scratch, only using rather long winded Grasshopper.
Now we use the Weaverbird plug-in to subdivide the faces and then project the vertices out onto a sphere via finding the closest points to a sphere and then recreating a convex hull to make a geodesic dome mesh:
Subdividing two times works fine but 3 times blows up convex hull, so I'll just have due with the the subdivision step and leave out projecting back to a sphere, since the algorithm already gives a nice spherical result that you can see inside this disaster:
Now you know what a standard geodescic dome is, just an icosahedron with faces divided into smaller triangles, projected out to a sphere.
Actually, the mere subdivision is just a bit blobby instead of a sphere, damn it, so I'll have to topologically recreate the mesh after projecting the points indeed back onto our sphere.
Using a subdivision plug-in may be slightly throwing the perfect result off, so manually creating subdivision points on each mesh face may be in order, doing them flat against each icosahedron face:
You can also start with the two other triangulated Platonic solids but those give less regular triangles:
…
a problem with SSL. Any Ideas? I am using the following code:
import json,httplib connection = httplib.HTTPSConnection('api.parse.com', 443) connection.connect() connection.request('GET', '/1/classes/MY-CLASS', '', { "X-Parse-Application-Id": "MY-APP-ID", "X-Parse-REST-API-Key": "MY-REST-API-KEY" }) result = json.loads(connection.getresponse().read()) print result
I Get the Following Messages:
Runtime error (IOException): Authentication failed because the remote party has closed the transport stream. Traceback: line 280, in do_handshake, "C:\Program Files\Rhinoceros 5.0 (64-bit)\Plug-ins\IronPython\Lib\ssl.py" line 120, in __init__, "C:\Program Files\Rhinoceros 5.0 (64-bit)\Plug-ins\IronPython\Lib\ssl.py" line 336, in wrap_socket, "C:\Program Files\Rhinoceros 5.0 (64-bit)\Plug-ins\IronPython\Lib\ssl.py" line 1156, in connect, "C:\Program Files\Rhinoceros 5.0 (64-bit)\Plug-ins\IronPython\Lib\httplib.py" line 3, in script Any help would be greatly appreciated! Thanks in advance! -Zach…
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));
}
}
}…
r." I'm sorry to hear that, I take the interface and ease-of-use rather seriously so this sounds like a fundamental failure on my part. On the other hand, Grasshopper isn't supposed to be on a par with most other 3D programs. It is emphatically not meant for manual/direct modelling. If you would normally tackle a problem by drawing geometry by hand, Grasshopper is not (and should never be advertised as) a good alternative."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."Grasshopper ships with about 1000 components (rounded to the nearest power of ten). I'm adding more all the time, either because new functionality has been exposed in the Rhino SDK or because a certain component makes a lot of sense to a lot of people. Adding pre-canned components that do the same as '8 or 10 components strung together' for the heck of it will balloon the total number of components everyone has to deal with. If you find yourself using the same 8 to 10 components together all the time, then please mention it on this forum. A lot of the currently existing components have been added because someone asked for it."[...] has a far cleaner and more intuitive interface. So does SolidWorks, Inventor, CATIA, NX, and a bunch of others."Again, GH was not designed to be an alternative to these sort of modellers. I don't like referring to GH as 'parameteric' as that term has been co-opted by relational modellers. I prefer to use 'algorithmic' instead. The idea behind parameteric seems to be that one models by hand, but every click exists within a context, and when the context changes the software figures out where to move the click to. The idea behind algorithmic is that you don't model by hand.This is not to say there is no value in the parametric approach. Obviously it is a winning strategy and many people love to use it. We have considered adding some features to GH that would make manual modelling less of a chore and we would still very much like to do so. However this is such a large chunk of work that we have to be very careful about investing the time. Before I start down this road I want to make sure that the choice I'm making is not 'lame-ass algorithmic modeller with some lame-ass parametrics tacked on' vs. 'kick-ass algorithmic modeller with no parametrics tacked on'.
Visual Programming.I'm not exactly sure I understand your grievance here, but I suspect I agree. The visual part is front and centre at the moment and it should remain there. However we need to improve upon it and at the same time give programmers more tools to achieve what they want.
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."Unfortunately it's not as simple as that. Whether or not a conversion between two data types makes sense is often dependent on the actual values. If you plug a list of curves into a Line component, none of them may be convertible. Should I therefore not allow this connection to be made? What if there is a single curve that could be converted to a line? What if you want to make the connection now, but only later plan to add some convertible curves to the data? What you made the connection back when it was valid, but now it's no longer valid, wouldn't it be weird if there was a connection you couldn't make again?I've started work on GH2 and one of the first things I'm writing now is the new data-conversion logic. The goal this time around is to not just try and convert type A into type B, but include information about what sort of conversion was needed (straightforward, exotic, far-fetched. etc.) and information regarding why that type was assigned.You are right that under some conditions, we can be sure that a conversion will always fail. For example connecting a Boolean output with a Curve input. But even there my preferred solution is to tell people why that doesn't make sense rather than not allowing it in the first place.
Sliders."I think they should be optional."They are optional."The “N” should turn into the number if set."What if you assign more than one integer? I think I'd rather see a component with inputs 'N', 'P' and 'X' rather than '5', '8' and '35.7', but I concede that is a personal preference."But if I plug it into something that'll only accept a 1, a 2, or a 3, that slider should self set accordingly."Agreed.
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."I was thinking of just zooming in on a component would eventually provide easier ways to access settings and data."Could some of these items disappear if they are contextually inappropriate or gray out if they're unlikely?"It's almost impossible for me to know whether these things are 'unlikely' in any given situation. There are probably some cases where a suggestion along the lines of "Hey, this component is about to run 40,524 times. It seems like it would make sense to Graft the 'P' input." would be useful.
Integration."Why isn't it just live geometry?"This is an unfortunate side-effect of the way the Rhino SDK was designed. Pumping all my geometry through the Rhino document would severely impact performance and memory usage. It also complicates the matter to an almost impossible degree as any command and plugin running in Rhino now has access to 'my' geometry."Maybe add more Rhino functionality to GH. GH has no 3D offset."That's the plan moving forward. A lot of algorithms in Rhino (Make2D, FilletEdge, Shelling, BlendSrf, the list goes on) are not available as part of the public SDK. The Rhino development team is going to try and rectify this for Rhino6 and beyond. As soon as these functions become available I'll start adding them to GH (provided they make sense of course).On the whole I agree that integration needs a lot of work, and it's work that has to happen on both sides of the isle.
Documentation.Absolutely. Development for GH1 has slowed because I'm now working on GH2. We decided that GH1 is 'feature complete', basically to avoid feature creep. GH2 is a ground-up rewrite so it will take a long time until something is ready for testing. During this time, minor additions and of course bug fixes will be available for GH1, but on a much lower frequency.Documentation is woefully inadequate at present. The primer is being updated (and the new version looks great), but for GH2 we're planning a completely new help system. People have been hired to provide the content. With a bit of luck and a lot of work this will be one of the main selling points of GH2.
2D-ness."I know you'll disagree completely, but I'm sticking to this. How else could an omission like offsetsurf happen?"I don't fully disagree. A lot of geometry is either flat or happens inside surfaces. The reason there's no shelling (I'm assuming that's what you meant, there are two Offset Surface components in GH) is because (a) it's a very new feature in Rhino and doesn't work too well yet and (b) as a result of that isn't available to plugins.
Organisation.Agreed. We need to come up with better ways to organise, document, version, share and simplify GH files. GH1 UI is ok for small projects (<100 components) but can't handle more complexity.
Don't get me wrong, I appreciate the feedback, I really do, but I want to be honest and open about my own plans and where they might conflict with your wishes. Grasshopper is being used far beyond the boundaries of what we expected and it's clear that there are major shortcomings that must be addressed before too long. We didn't get it right with the first version, I don't expect we'll get it completely right with the second version but if we can improve upon the -say- five biggest drawbacks (performance, documentation, organisation, plugin management and no mac version) I'll be a happy puppy.
--
David Rutten
david@mcneel.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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