whole design intent, but this is what Inventor is good at. The way it packages bits of 'scripted' components into 'little models' that can be stored and re-assembled is central to MCAD working.
The Inventor model shown is almost 5 years old. We don't model like that any more, however it does offer a good idea of general MCAD modeling approaches.
iParts is useful in certain situations, it could've been useful in the above model, its usefulness is often in function of the quantity of variants/configurations.
So much is scripted in GH, maybe it should also be possible to script/define/constrain/assist the placement/gluing of the results?
...
Starting point: I think we are talking across purposes. AFAIK, the solving sequence of GH's scripted components is fixed. It won't do circular dependencies... without a fight. The inter-component dependencies not 'managed' like constraints solvers do for MCAD apps.
Components and assemblies are individual files in MCAD.
Placement of these within assemblies in MCAD is a product of matrix transforms and persistent constraints. There is no bi-directional link, the link is unidirectional (downflow only), because of the use of proxies.
Consequently, scripting the placement of components is irrelevant in GH, unless you decide that each component needs to be contained in its own separate file.
This also brings up the point that generating components and assemblies in MCAD is not as straightforward. In iParts and iAssemblies, each configuration needs to be generated as a "child" (the individual file needs to be created for each child) before those children can be used elsewhere.
You notice the dilemma, if you generate 100 parts, and then you realize you only need 20, you've created 80 extra parts which you have no need for, thus generating wasteful data that may cause file management issues later on.
GH remains in a transient world, and when you decide to bake geometry (if you need to at all), you can do that in one Rhino file, and save it as the state of the design at that given moment. Very convenient for design, though unacceptable for most non-digital manufacturing methods, which greatly limits Rhino's use for manufacturing unless you combine it with an MCAD app.
One of the reasons why the distributed file approach makes perfect sense in MCAD, is that in industry you deal with a finite set of objects. Generative tools are usually not a requirement. Most mechanical engineers, product engineers and machinists would never have any use for that.
The other thing that MCAD apps like Inventor have, is the 'structured' interface that offers up all that setting out information like the coordinate systems, work planes, parameters etc in a concise fashion in the 'history tree'. This will translate into user speed. GH's canvas is a bit more freeform. I suppose the info is all there and linked, so a bit of re-jigging is easy. Also, see how T-Flex can even embed sliders and other parameter input boxes into the model itself. Pretty handy/fast to understand, which also means more speed.
True. As long as you keep the browser pane/specification tree organized and easy to query.
:)
Would love to understand what you did by sketching.
I'll start by showing what was done years ago in the Inventor model, and then share with you what I did in GH, but in another post.
Let's use one of the beams as an example:
We can isolate this component for clarity.
Notice that I've highlighted the sectional sketch with dimensions, and the point of reference, which is in relation to the CL of the column which the beam bears on. The orientation and location of the beam is already set by underlying geometry.
Here's a perspective view of the same:
The extent of the beam was also driven by reference geometry, 2 planes offset from the beam's XY plane, driven by parameters from another underlying file which serves as a parameter container:
Reference axes and points are present for all other components, here are some of them:
It starts getting cluttered if you see the reference planes as well:
Is I mentioned earlier, over time we've found better ways to define and associate geometry, parameters, manage design change, improving the efficiency of parametric models. But this model is a fair representation of a basic modeling approach, and since an Inventor-GH comparison is like comparing apples and oranges anyways, this model can be used to understand the differences and similarities, for those interested.
I haven't even gotten to your latest post yet, I will eventually.…
Added by Santiago Diaz at 10:36am on February 26, 2011
.
Things have been working swimmingly in many areas of the plugin, but one particular problem has been tough to solve. I have two components that are trying to read/write to the same memory at the same time, causing Rhino exceptions and crashes.
The conflicts appear to be happening between two components -- one is a "Layer Events Listener" that reports essentially what type of layer event just happened. The other is a "Set Layer Visibility" component that toggles the visibility of a list of layers.
The code:
public class LayerTools_LayerEventsListener : GH_Component { /// <summary> /// Initializes a new instance of the LayerTools_LayerListener class. /// </summary> public LayerTools_LayerEventsListener() : base("Layer Events Listener", "Layer Listener", "Get granular information about the layer events happening in the Rhino document.", "Squirrel", "Layer Tools") { }
/// <summary> /// Registers all the input parameters for this component. /// </summary> protected override void RegisterInputParams(GH_Component.GH_InputParamManager pManager) { pManager.AddBooleanParameter("Active", "A", "Set to true to listen to layer events in the Rhino document.", GH_ParamAccess.item, false); pManager.AddTextParameter("Exclusions", "E", "Provide a list of exclusions to stop reading specific events (Added, Deleted, Moved, Renamed, Locked, Visibility, Color, Active).", GH_ParamAccess.list); pManager[1].Optional = true; }
/// <summary> /// Registers all the output parameters for this component. /// </summary> protected override void RegisterOutputParams(GH_Component.GH_OutputParamManager pManager) { pManager.AddBooleanParameter("Initialized", "I", "Whether the listener changed from passive to active.", GH_ParamAccess.item); pManager.AddTextParameter("Document Name", "doc", "Name of the Rhino document that is changing.", GH_ParamAccess.item); pManager.AddTextParameter("Layer Path", "path", "Path of the modifed layer.", GH_ParamAccess.item); pManager.AddIntegerParameter("Layer Index", "ID", "Index of the modified layer.", GH_ParamAccess.item); pManager.AddIntegerParameter("Sort Index", "SID", "Sort index of the modified layer.", GH_ParamAccess.item); pManager.AddTextParameter("Event Type", "T", "Type of the modification.", GH_ParamAccess.item); pManager.AddBooleanParameter("Added", "A", "If the layer has been added.", GH_ParamAccess.item); pManager.AddBooleanParameter("Deleted", "D", "If the layer has been deleted.", GH_ParamAccess.item); pManager.AddBooleanParameter("Moved", "M", "If the layer has been moved.", GH_ParamAccess.item); pManager.AddBooleanParameter("Renamed", "R", "If the layer has been renamed.", GH_ParamAccess.item); pManager.AddBooleanParameter("Locked", "L", "If the layer locked setting has changed.", GH_ParamAccess.item); pManager.AddBooleanParameter("Visibility", "V", "If the layer's visibility has changed.", GH_ParamAccess.item); pManager.AddBooleanParameter("Color", "C", "If the layer's color has changed.", GH_ParamAccess.item); pManager.AddBooleanParameter("Active", "Act", "If the active layer has changed.", GH_ParamAccess.item); }
/// <summary> /// This is the method that actually does the work. /// </summary> /// <param name="DA">The DA object is used to retrieve from inputs and store in outputs.</param> protected override void SolveInstance(IGH_DataAccess DA) { bool active = false; List<string> exclusions = new List<string>();
DA.GetData(0, ref active); DA.GetDataList(1, exclusions);
RhinoDoc thisDoc = null;
bool initialize = false;
string dName = null; string activePath = null; int layerIndex = -1; int sortIndex = -1; string eventType = null; bool added = false; bool deleted = false; bool moved = false; bool renamed = false; bool locked = false; bool visibility = false; bool color = false; bool current = false;
if (active) { thisDoc = RhinoDoc.ActiveDoc;
initialize = (!previouslyActive) ? true : false;
RhinoDoc.LayerTableEvent -= RhinoDoc_LayerTableEvent; RhinoDoc.LayerTableEvent += RhinoDoc_LayerTableEvent; previouslyActive = true;
} else {
RhinoDoc.LayerTableEvent -= RhinoDoc_LayerTableEvent; previouslyActive = false; }
if (ev != null) { dName = ev.Document.Name; layerIndex = ev.LayerIndex; eventType = ev.EventType.ToString();
if (!exclusions.Contains("Active")) { if (ev.EventType.ToString() == "Current") { // active layer has just been changed current = true; }
}
if (!exclusions.Contains("Moved")) { if (ev.EventType.ToString() == "Sorted") { // active layer has just been changed moved = true; }
}
if (!exclusions.Contains("Added")) { if (ev.EventType.ToString() == "Added") { // layer has just been added activePath = ev.NewState.FullPath; added = true; }
}
if (!exclusions.Contains("Active")) { if (ev.EventType.ToString() == "Deleted") { // layer has just been added
deleted = true; } }
if (ev.EventType.ToString() == "Modified") { // layer has been modified activePath = ev.NewState.FullPath;
//skip sortindex eventType = ev.EventType.ToString();
if (ev.OldState != null && ev.NewState != null) { if (!exclusions.Contains("Locked")) { if (ev.OldState.IsLocked != ev.NewState.IsLocked) locked = true;
} if (!exclusions.Contains("Visibility")) { if (ev.OldState.IsVisible != ev.NewState.IsVisible) visibility = true; }
if (!exclusions.Contains("Moved")) { if (ev.OldState.ParentLayerId != ev.NewState.ParentLayerId) moved = true; }
//if (ev.OldState.SortIndex != ev.NewState.SortIndex) moved = true; if (!exclusions.Contains("Renamed")) { if (ev.OldState.Name != ev.NewState.Name) renamed = true; }
if (!exclusions.Contains("Color")) { if (ev.OldState.Color != ev.NewState.Color) color = true; } }
} }
DA.SetData(0, initialize); DA.SetData(1, dName); DA.SetData(2, activePath); DA.SetData(3, layerIndex); DA.SetData(4, sortIndex); DA.SetData(5, eventType); DA.SetData(6, added); DA.SetData(7, deleted); DA.SetData(8, moved); DA.SetData(9, renamed); DA.SetData(10, locked); DA.SetData(11, visibility); DA.SetData(12, color); DA.SetData(13, current);
}
static bool previouslyActive = false; Rhino.DocObjects.Tables.LayerTableEventArgs ev = null;
void RhinoDoc_LayerTableEvent(object sender, Rhino.DocObjects.Tables.LayerTableEventArgs e) { ev = e;this.ExpireSolution(true); }
And for the layer visibility component:
public LayerTools_SetActiveLayer() : base("Set Active Layer", "SetActiveLayer", "Set the active layer in the Rhino document.", "Squirrel", "Layer Tools") { }
/// <summary> /// Registers all the input parameters for this component. /// </summary> protected override void RegisterInputParams(GH_Component.GH_InputParamManager pManager) { pManager.AddBooleanParameter("Active", "A", "Set to true to change the active layer in Rhino.", GH_ParamAccess.item, false); pManager.AddTextParameter("Path", "P", "Full path of the layer to be activated.", GH_ParamAccess.item); }
/// <summary> /// Registers all the output parameters for this component. /// </summary> protected override void RegisterOutputParams(GH_Component.GH_OutputParamManager pManager) { pManager.AddIntegerParameter("Layer ID", "ID", "Index of layer that has been activated.", GH_ParamAccess.item); pManager.AddBooleanParameter("Status", "St", "True when the layer has been activated.", GH_ParamAccess.item); }
/// <summary> /// This is the method that actually does the work. /// </summary> /// <param name="DA">The DA object is used to retrieve from inputs and store in outputs.</param> protected override void SolveInstance(IGH_DataAccess DA) { bool active = false; string path = "";
if (!DA.GetData(0, ref active)) return; if (!DA.GetData(1, ref path)) return;
int layer_index = -1; bool status = false;
if (path != null) {
Rhino.RhinoDoc doc = Rhino.RhinoDoc.ActiveDoc; Rhino.DocObjects.Tables.LayerTable layertable = doc.Layers;
layer_index = layertable.FindByFullPath(path, true);
if (layer_index > 0) { // if exists RhinoDoc.ActiveDoc.Layers.SetCurrentLayerIndex(layer_index, true); status = true; } }
DA.SetData(0, layer_index); DA.SetData(1, status); }
Now originally I was getting exceptions when changing multiple layers' visibility properties, which would cause the Event Listener to fire and try to read the Visibility property before the memory has been released by the Set Layer Visibility component. That led me to add an "Exceptions" input, that would allow me to disable the reading of Visibility events at the source in the Layer Events listener. That helped me manage about 95% of the crashes I was getting, but I still get strange crashes in other event properties, even when that property shouldn't be affected. For instance, I am getting a crash here on the Name property in the event from the delegate function, even though I am only changing Visibility at any one time:
I have a few ideas but they all seem pretty hacky. One is to try to set a flag that is readable by any component in the plugin -- so that the event listener can see if a "set" component is currently running and abort before causing an exception. The other is creating a delay in the event listener, somthing like 200ms, to allow any set components to finish what they are doing before reading the event. Neither seems super ideal.
Any ideas?
Thanks,
Marc
…
edit 29/04/14 - Here is a new collection of more than 80 example files, organized by category:
KangarooExamples.zip
This zip is the most up to date collection of examples at the moment, and collects t
currently within a fake euphoria framework - blame China/UAE) and a potential decision about doing/developing this or doing that … well …anyway … read and enjoy.
AEC matters: The good, the bad and the ugly.
The bad news: Rhino is NOT suitable for the job (although some use it … but only in the sense that people use Modo for the so called “hard modeling”). By job I mean things up to shop drawing level + specs + you and me (we call it Final level) – nothing to do with sketches and outlines of some abstract “schematic” topology.
The ugly news: The so called Design-Construct approach gains exponentially momentum especially in countries the likes of China/UAE/BRICS (95% of the whole AEC activity worldwide happens there). DeCo means: AEC engineers deliver some kind of study in a preliminary level and the main contractor splits (outsourcers) the job and assigns the study completion AND the construction to various sup-constructors. That thing appeared first – in a large scale - in Dubai 15 years ago. This means that the era of Sergio Pininfarina is over and out: welcome anonymous Toyota designer. In plain English: days of construction corporations fast replacing practices. Dead men walking.
The good news: All AEC related apps (Revit, AECOsim, Allplan and the likes) are in a lethargic state as regards the brave new world (based on the archaic level driven organization schemas etc etc). Of course they all claim the exact opposite and point that support BIM (nobody mention PLM) better than the other guy. But the 21st century – helped by 2 forthcoming unavoidable crisis (a) about shortage of water (b) about transition from carbon to hydrogen economy – isn’t about bureaucracy: think cost/resources optimization and “fitness” rather than China/UAE type of liquid trend. Days of euphoria fast approaching the Wall.
Top to bottom and visa versa.
Old days Titans (Oscar, Mies, Walter, Pierre Luigi, Frank, Eero, blah blah) outlined things (mostly using crayons) and the rest were struggling to translate these in reality in an one way vector like process : Top to bottom that is. These days the inverse gains momentum : when in the whole consider the part … validate … redo … validate … redo. This means bottom to top geared with top-to-bottom. In plain English : child imposes rules to parent and parent imposes rules to child. This means classic MCAD feature/history modeling (CATIA/NX/MS). This is something that Rhino can’t do (not to mention that Rhino is a surface modeler – a rather critical fact).
The parts that are bigger than the whole.
Go there ( http://www.behance.net/gallery/2885057/a-myriad-of-cables) are inspect the whole thing: it’s a parametric nightmare made with the other guy (Generative Components – slower than a Skoda + bugs + why bother?). But the whole (masts and membranes and the likes) means nothing here: focus to the details that are critical for connecting this with that. Complex feature driven solids that are made with internal (on a per se basis) parameters (like fillets required for casting or radius for cable anchoring) whilst they comply with external rules/parameters (cable angles, topology clash issues etc etc). So the whole outlines possibilities … and the part either can follow…or the part must change…or the whole must change. Can you do that with GH/Rhino? And if not what’s missing? (lot’s of things to be honest).
Some other "similar" things:
The narrow picture.
I agree with what others already said and with pretty much all Ola’s points – especially the visual drag-and-drop path mapper (i.e. a visual data manipulator so to speak) and the enable/disable components in groups capability.
Some other suggestions:
A multi canvas capability. As things are right now…it’s like working in Rhino in one view (rather unsuitable I guess). In fact …since overlapping views they don’t work in Rhino…well…you know, he he.
A working auto profile arrangement capability (non twisted Loft/Sweep and the likes). Worth 1Bn dollars that one.
Ability to locate components that caused this or that in the Rhino view: meaning a 2 way communication approach : GH makes things happen in Rhino and things can indicate their cause in the GH canvas.
A robust collection of components that bake stuff in nested blocks (emulating some primitive assembly/component way of thinking). Why may you ask? Well … the whole objective is to talk to CATIA (via STEP) don’t you agree? CATIA makes things happen in real-life not Rhino.
A robust collection of components that can create real-life parametric tensile membrane solutions (get some inspiration from FormFinder: useless because it’s academic but good to point the way). Membranes (and geodesics) are the future.
I could continue at infinitum but IMHO the big picture is worth 12345,67 “focused” GH improvements.
May the Force (the dark option) be with us all.
…
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.
…
Introduction to Grasshopper Videos by David Rutten.
Wondering how to get started with Grasshopper? Look no further. Spend an some time with the creator of Grasshopper, David Rutten, to learn the