..
The problem is that using the index, adding a activies, the next activies change the index and then the link is wrong.
example: I need to connect to hotel function with house function, therefore i have 0 and 4 index in my panel.. So i have to extract the index linked to the alphabetical value to be able to draw lines between the points associated to the names of activities. Now if i add a new string between the values, the house activity hasn't the original index 4 but the new index 5. So the link will be not created between hotel and house but hotel e new activity in the index 4.
…
This is the actual reason I'm going through all this. I want to develop an algorithm that can be applied consistently and produce good results.
Here is a a little background. I'm working on my master's thesis in structural analysis. My thesis is on seismic behaviour of a roman temple in Portugal. I will be using a method of analysis suitable for block structures called the discrete element method. I am using a commercial code called 3DEC for this.
Now in order to the analysis I need to construct a 3D block model of my structure. I received a 3D scan of the entire structure (in *.wrl) format and spent a week trying to clean it up and slice it into the blocks that make up the structure. Now I want to use the scanned geometry of the blocks and describe a simplified prism around each that will represent the block in my analysis. I've attached a file with one of the columns in the temple. I think (at least with my tests so far) that it is representative of the all the blocks I'm dealing with.
Now my criteria for creation of the blocks:
I would like the contact area between the blocks to be as close as possible to the actual drum contact area,
I would like to get the volume of the blocks to be as close as possible (secondary to the contact area) to the volume of the actual drums in order to insure that the weight distribution in the structure is as close to reality as possible,
I would like the shape of the contact area to be as close to reality as possible
I order to satisfy all these requirements, I've done the following in my grasshopper file:
I take a section at the top and bottom of each of the drum meshes. I use this to extract the contact outline at the top and bottom of the drum. This is sometimes problematic and requires me to clean up the model and remove features that interfere.
Next I take each surface and try to fit a minimum circle around it. I try to do this because in my mind this is the best possible way to find the actual centre of the drum when there is cut outs and deterioration. This works well as long as more than half of the contact surface is still in its circular shape (third block from bottom in the example file doesn't satisfy this requirement and thus causes problems).
Knowing the centre, I use an algorithm I created in VB to search for one of the flutes on the contact profile. My ideas is that if I can find one of the flutes, I can then find the others by just going around at 30 degrees (there are 12 flutes) and find the location of all the flutes. In the VB code I've tried to explain my algorithm so I won't explain it here. I also think this algorithm is needlessly complicated and stupid as I'll explain later.
Once I've got one of the flutes, I just find the intersection of a line with at every 30 degrees with the outline curve.
Having all (12) points around the perimeter, I use an loop to scale the shape around the centre of the circle I found in step 1 to get the area within a tolerance value of the actual contact area (satisfying requirement 1). I was using HoopSnake before, but it required resetting every time so I decided to write my own thing.
I then connect the points on both top and bottom to get a solid block.
Now the problems are as follows:
Sometimes the algorithm doesn't find the best location as the starting point. As I said an important thing is that the circle is tangent to the flutes and that is true only if the column profile is larger than a half-circle.
The software I use requires convex blocks. I've tried to remedy this by using convex hull component before step 5 to insure the surfaces are convex.
I'm having issues sometimes with the alignment of top and bottom points. I think I just need to implement a component that sorts the points around a single basis so that there is no twisting.
I've been experimenting with convex hull as a general approach for defining the corner points, but I'm having problem take the convex hull curve and breaking it into a 12 sided polygon, preserving as much as possible the location of the flutes and the general shape of the contact surface.
I'm really sorry about the long post and complicated question. I hope someone can give some pointers on what I could try. I understand that this is not an easy question and that it is more a question of doing something rather than asking about grasshopper itself. My goal is to have an algorithm that I can explain as a general method for others to use in the future when dealing with these structures. This is only a small minor part of my thesis (the analysis is what is important) but it is taking a lot of time to figure out.
If you have any other questions, I would be more than happy to provide a better explanation. In the file I have created a region with all my input parameters. You can choose a different mesh from that point and change various settings. I hope that is self-explanatory.
Thanks for all your help,
Ali
BTW: I'm really sorry for the poor way I've done this stuff so far. I'm not a programmer and apart from some small macros in Excel I don't know much about this stuff. To add to that, I've just started with Rhino and Grasshopper about five days ago after almost pulling out all my hair trying to do this with AutoCAD!…
o my python component returning null despite running fine in the standalone python editor (i.e.: not through grasshopper).The original python script is as follows:
import randomimport rhinoscriptsyntax as rsrs.EnableRedraw(False)
def placeBuildings(curve, distance): pts=rs.DivideCurveLength(curve,5) counter=0 for myPoint in pts: counter=counter+1 #get the parmeter f current positision param=rs.CurveClosestPoint(curve,myPoint) #get teh tangent of this parameter tangent=rs.CurveTangent(curve,param) #calculate the angle of the tangent angle=rs.Angle((0,0,0),tangent) randomNumber=random.uniform(1,5) heightOfBuilding=random.uniform(4,40) rect=rs.AddRectangle(rs.WorldXYPlane(),randomNumber,2) rs.MoveObject(rect,(0,randomNumber,0)) hull=rs.ExtrudeCurveStraight(rect,(0,0,0),(0,0,heightOfBuilding)) rs.RotateObject(hull,(0,0,0),angle[0]) rs.MoveObject(hull,myPoint) #if counter%4: #rs.AddCircle(myPoint,3) #selection of curve#curveParameter=rs.GetCurveObject("sel curve")#curve=curveParameter[0]
curves=rs.GetCurveObject("select streets",4)distance=rs.GetInteger("distance?",4)for curve in curves: placeBuildings(curve,distance) rs.ReverseCurve(curve) placeBuildings(curve,distance)
When placed in grasshopper it is the following:
import randomimport rhinoscriptsyntax as rs
#randomNumber=random.uniform(1,5)#rs.AddCircle((0,randomNumber,0), 2)
def placeBuildings(curve, distance): pts=rs.DivideCurveLength(curve, 5) counter=0 for myPoint in pts: counter=counter+1 #get the parmeter f current positision param=rs.CurveClosestPoint(curve,myPoint) #get teh tangent of this parameter tangent=rs.CurveTangent(curve,param) #calculate the angle of the tangent angle=rs.Angle((0,0,0),tangent) randomNumber=random.uniform(1,5) heightOfBuilding=random.uniform(4,40) rect=rs.AddRectangle(rs.WorldXYPlane(),randomNumber,2) rs.MoveObject(rect,(0,randomNumber,0)) hull=rs.ExtrudeCurveStraight(rect,(0,0,0),(0,0,heightOfBuilding)) rs.RotateObject(hull,(0,0,0),angle[0]) rs.MoveObject(hull,myPoint)
#selection of curve#curveParameter=rs.GetCurveObject("sel curve")#curve=curveParameter[0]
curves=xdistance=y
for curve in curves: placeBuildings(curve,distance) rs.ReverseCurve(curve) placeBuildings(curve,distance)
I am unsure why there is no error being returned yet I cannot achieve any result other than null. Maybe someone could look at the script and tell me what is going wrong? I'm hoping to solve this before next Thursday so I might be asking for too much.
Much Appreciated.-A…
Added by Adem O'Byrne at 11:45am on October 9, 2014
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.
…
What is it?Bumblebee is a set of user objects which connect Microsoft Excel and Grasshopper.
The current component set allows for not just the transfer of data back and forth between GH and XL but giv
rsistant data , as the inputs and outputs of the component should be build by the data stored in the object.
thanxs in advance
Michael
here is the code of the object....
public class Proxy { public List<string> _name_in; public List<string> _name_out; public List<SerializableType> _type_in; public List<SerializableType> _type_out; public List<GH_ParamAccess> _access_in; public string _path; public string _script; public bool _internalized; public bool _working; public Proxy(List<string> name_in, List<string> name_out, List<SerializableType> type_in, List<SerializableType> type_out, List<GH_ParamAccess> access_in, string path, string script, bool internalized) { _name_in = name_in; _name_out = name_out; _type_in = type_in; _type_out = type_out; _access_in = access_in; _path = path; _script = script; _internalized = internalized; _working = true; } public Proxy() { _name_in = new List<string>(); _name_out = new List<string>(); _type_in = new List<SerializableType>(); _type_out = new List<SerializableType>(); _access_in = new List<GH_ParamAccess>(); _path = get_path_of_plugin(); _script = ""; _internalized = false; _working = false; } public static string get_path_of_plugin() { string temp_cut; string string_path = System.Reflection.Assembly.GetExecutingAssembly().Location; string string_name = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name; int temp_name_int = string_name.Length + 5; int temp_path_int = string_path.Length; temp_cut = string_path.Remove(temp_path_int - temp_name_int); return temp_cut; } public static T ObjectDeserializer<T>(string XmlInput) { System.Xml.XmlDocument XmlDoc = new System.Xml.XmlDocument(); XmlDoc.Load(new System.IO.StringReader(XmlInput)); System.Xml.Serialization.XmlSerializer ser = new System.Xml.Serialization.XmlSerializer(typeof(T)); T out_ob = (T)ser.Deserialize(new System.IO.StringReader(XmlInput)); return out_ob; } public static string ObjectSerializer<T>(T SerializedObject) { System.Xml.Serialization.XmlSerializer ser = new System.Xml.Serialization.XmlSerializer(typeof(T)); System.Text.StringBuilder builder = new System.Text.StringBuilder(); XmlWriter xmllol = XmlWriter.Create(builder); ser.Serialize(xmllol, SerializedObject); return builder.ToString(); } } public class SerializableType { private Type type; // when serializing, store as a string // [DataMember] public string TypeString { get { if (type == null) return null; return type.FullName; } set { if (value == null) type = null; else { type = Type.GetType(value); } } } public Type return_Type() { return type; } // constructors public SerializableType() { type = null; } public SerializableType(Type t) { type = t; } // allow SerializableType to implicitly be converted to and from System.Type static public implicit operator Type(SerializableType stype) { return stype.type; } static public implicit operator SerializableType(Type t) { return new SerializableType(t); } // overload the == and != operators public static bool operator ==(SerializableType a, SerializableType b) { // If both are null, or both are same instance, return true. if (System.Object.ReferenceEquals(a, b)) { return true; } // If one is null, but not both, return false. if (((object)a == null) || ((object)b == null)) { return false; } // Return true if the fields match: return a.type == b.type; } public static bool operator !=(SerializableType a, SerializableType b) { return !(a == b); } // we don't need to overload operators between SerializableType and System.Type because we already enabled them to implicitly convert public override int GetHashCode() { return type.GetHashCode(); } // overload the .Equals method public override bool Equals(System.Object obj) { // If parameter is null return false. if (obj == null) { return false; } // If parameter cannot be cast to SerializableType return false. SerializableType p = obj as SerializableType; if ((System.Object)p == null) { return false; } // Return true if the fields match: return (type == p.type); } public bool Equals(SerializableType p) { // If parameter is null return false: if ((object)p == null) { return false; } // Return true if the fields match: return (type == p.type); } } public class GH_Proxy : Grasshopper.Kernel.Types.GH_Goo<Proxy> { public override Grasshopper.Kernel.Types.IGH_Goo Duplicate() { return this; } public override bool IsValid { get { return true; } } public override string ToString() { return Proxy.ObjectSerializer<Proxy>(this.Value); } public override string TypeDescription { get { return "his is a proxy"; } } public override string TypeName { get { return "his is a proxy"; } } }…
e 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.
I get that. That’s why that 3D shape I’m trying to apply the voronoi to was done in NX. I do wonder where the GUI metaphor GH uses comes from. It reminds me of LabVIEW.
"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.
It’s not the primary components that catalyzed this thought but rather the secondary components. I was toying with a component today (twist from jackalope) that made use of three toggle components. The things they controlled are checkboxes in other apps.
Take a look at this jpg. Ignore differences; I did 'em quickly. GH required 19 components to do what SW did with 4 commands. Note the difference in screen real estate.
As an aside, I really hate SolidWorks (SW). But going forward, I’ll use it as an example because it’s what most people are familiar with.
"[...] 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.
I agree, and disagree. I believe parametric applies equally to GH AND SW, NX, and so forth, while algorithmic is unique to GH (and GC and Dynamo I think). Thus I understand why you prefer the term. I too tend to not like referring to GH as a parametric modeler for the same reason.
But I think it oversimplifies it to say parametric modelers move the clicks. SW tracks clicks the same way GH does; GH holds that information in geometry components while SW holds it in a feature in the feature tree. In both GH and SW edits to the base geometry will drive a recalculation, but more commonly, it’s an edit to input data, beit equations or just plain numbers, that drive a recalculation.
I understand the difference in these programs. What brought me to GH is that it can create a visual dialog that standard modelers can’t. But as I've grown more comfortable with it I’ve come to realize that the GUI of GH and the GUI of other parametric modelers, while looking completely different, are surprisingly interchangeable. Do not misconstrue that I’m suggesting that GH should replace it’s GUI with SW’s. I’m not. I refrain from suggesting anything specific. I only suggest that you allow yourself to think radically.
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'.
Given a choice, I'd pick kick-ass algorithmic modeller with no parametrics tacked on.
2. 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.
I'll admit, this is a bit tough to explain. As I've re-read my own comment, I think it was partly a precursor to the context sensitivity point and touched upon other stated points.
This now touches upon my own ignorance about GH’s target market. Are you moving toward a highly specialized tool for programmers and/or mathematicians, or is the intent to create a tool that most designers can master? If it’s the former, rock on. You’re doing great. If it’s the latter, I’m one of the more technically sophisticated designers I know and I’m lost most of the time when using GH.
GH allows the same freedom as a command line editor. You can do whatever you like, and it’ll work or not. And you won’t know why it works or doesn't until you start becoming a bit of an expert and can actually decipher the gibberish in a panel component. I often feel GH has the ease of use of DOS with a badass video card in front.
Please indulge my bit of storytelling. Early 3D modelers, CATIA, Unigraphics, and Pro-Engineer, were unbelievably difficult to use. Yet no one ever complained. The pain of entry was immense. But once you made it past the pain threshold, the salary you could command was very well worth it. And the fewer the people who knew how to use it, the more money you could demand. So in a sense, their lack of usability was a desirable feature among those who’d figured it out.
Then SolidWorks came along. It could only do a fraction of what the others did, but it was a fraction of the cost, it did most of what you needed, and anyone could figure it out. There was even a manual on how to use it. (Craziness!) Within a few short years, the big three all had to change their names (V5, NX, and Wildfire (now Creo)) and change the way they do things. All are now significantly easier to use.
I can tell that the amount of development time that’s gone into GH is immense and I believe the functionality is genius. I also believe it’s ease of use could be greatly improved.
Having re-read my original comments, I think it sounded a bit snotty. For that I apologize.
3. 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 [...] 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.
You bring up both interesting points and limits to my understanding of coding. I’ve reached the point in my learning of GH where I’m just getting into figuring out the sets tab (and so far I’m not doing too well). I often find myself wondering “Is all of this manual conditioning of the data really necessary? Doesn’t most software perform this kind of stuff invisibly?” I’d love to be right and see it go away, but I could easily be wrong. I’ve been wrong before.
5. 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.
I kinda like this. It’s a continuation of what you’re currently doing with things like the panel component.
"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.
6. 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.
You work for McNeel yet you seem to speak of them as a separate entity. Is this to say that there are technical reasons GH can only access things through the Rhino SDK? I’d think you would have complete access to all Rhino API’s. I hope it’s not a fiefdom issue, but it happens.
7. 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.
It begs the question that I have to ask. When is GH1.0 scheduled to launch? And if you need another person to proofread the current draft of new primer.
patrick@girgen.com
I can’t believe wikipedia has an entry for feature creep. And I can’t believe you included it. It made me giggle. Thanks.
8. 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.
I believe it’s been helpful for me to have figured this out. I recently completed a GH course at a local Community College and have done a bunch of online tutorials. The first real project I decided to tackle has turned out to be one of the more difficult things to try. It’s the source of the questions I posted. (Thanks for pointing out that they were posted in the wrong spot. I re-posted to the discussions board.)
I just can't seem to figure out how to turn the voronoi into legitimate geometry. I've seen this exact question posted a few times, but it’s never been successfully answered. What I'm showing here is far more angular than I’m hoping for. The mesh is too fine for weaverbird to have much of an effect. And I haven't cracked re-meshing. Btw, in product design, meshes are to be avoided like the plague. Embracing them remains difficult.
As for offsetsurf, in Rhino, if you do an offsetsurf to a solid body, it executes it on all sides creating another neatly trimmed body thats either larger or smaller than the original. This is how every other app I know of works. GH’s offsetsurf creates a bunch of unjoined faces spaced away from the original brep. A common technique for 3D voronois (Yes, I hit the voronoi overuse easter egg) is to find the center of each cell and scale them by this center. If you think about it, this creates a different distance from the face of the scaled cell to the face of the original cell for every face. As I've mentioned, this project is giving me serious headaches.
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.
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David Rutten
Thank you for taking the time to reply David. Often we feel that posting such things is send it into the empty ether. I’m very glad that this was not the case.
And thank you for all of the work you've put into GH. If you found any of my input overly harsh or ill-mannered, I apologise. It was not my intent. I'm generally not the ranting sort. If I hadn't intended to provide possibly useful input, I wouldn't have written.
Cheers
Patrick Girgen
Ps. Any pointers on how to get a bit further on the above project would be greatly appreciated.
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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