.
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
…
curve or locus] of a segment AB, in English. The set of all the points from which a segment, AB, is seen under a fixed given angle.
When you construct l'arc capable —by using compass— you obviously need to find the centre of this arc. This can be easily done in GH in many ways by using some trigonometry (e.g. see previous —great— solutions). Whole circles instead of arcs provide supplementary isoptics —β-isoptic and (180º-β)-isoptic—. Coherent normals let you work in any plane.
Or you could just construct β-isoptics of AB by using tangent at A (or B). I mean [Arc SED] component.
If you want the true β-isoptic —the set of all the points— you should use {+β, -β} degrees (2 sides; 2 solutions; 2 arcs), but slider in [-180, +180] degrees provides full range of signed solutions. Orthoptic is provided by ±90º. Notice that ±180º isoptic is just AB segment itself, and 0º isoptic should be the segment outside AB —(-∞, A] U [B, +∞)—. [Radians] component is avoidable.
More compact versions can be achieved by using [F3] component. You can choose among different expressions the one you like the most as long as performs counter clockwise rotation of vector AB, by 180-β degrees, around A; or equivalent. [Panel] is totally avoidable.
Solutions in XY plane —projection; z = 0—, no matter A or B, are easy too. Just be sure about the curve you want to find the intersection with —Curve; your wall— being contained in XY plane.
A few self-explanatory examples showing features.
1 & 5 1st ver. (Supplementary isoptics) (ArcCapableTrigNormals_def_Bel.png)
2 & 6 2nd ver. (SED) (ArcCapableSED_def_Bel.png)
3 & 7 3rd ver. (SED + F3) (ArcCapableSEDF3_def_Bel.png)
4 & 8 4th ver. (SED + F3, Projection) (ArcCapableSEDProjInt_def_Bel.png)
If you want to be compact, 7 could be your best choice. If you prefer orientation robustness, 5. Etcetera.
I hope these versions will help you to compact/visualize; let me know any feedback.
Calculate where 2 points [A & B] meet at a specific angle is just find the geometrical locus called arco capaz in Spanish, arc capable in French (l'isoptique d'un segment de droite) or isoptic [curve or locus]
of a segment AB, in English. The set of all the points from which a segment,
AB, is seen under a fixed given angle.…
peuvent se diviser une surface avec ne importe quel motif imaginable. 3. Ici, je fournir un moyen de le faire via Lunchbox ... cela fonctionne mais il est fixe et donc nous avons besoin de jouer avec des arbres de données afin de créer le motif approprié par cas. 4. L'autre composante est un joint C # qui fait beaucoup de choses autres que de diviser ne importe quelle collection de points avec de nombreux modèles (voir le modèle ANDRE que je ai fait pour vous). 5. Vous devez décomposer une polysurface en morceaux afin de travailler sur les subdivisions. 6. Je donne une autre définition ainsi que pourrait agir comme un tutoriel sur la façon de traiter des ensembles de points via des composants de GH standards et des méthodes classiques.
Avertissez si tous ceux-ci apparaissent floue pour vous: Si oui, je pourrais écrire une définition utilisant des composants de GH classiques - mais vous perdrez les variations de motifs de division.
mieux, Peter
…
ing the maps to the broader community.
At the moment, there are just a few known issues left that I have to fix for complex geometric cases but they should run smoothly for most energy models that you generate with Honeybee. Within the next month, I will be clearing up these last issues and, by the end of the month, there will be an updated youtube tutorial playlist on the comfort tools and how to use them.
In the meantime, there's an updated example file (http://hydrashare.github.io/hydra/viewer?owner=chriswmackey&fork=hydra_2&id=Indoor_Microclimate_Map) and I wanted to get you all excited with some images and animations coming out of the design part of my thesis. I also wanted to post some documentation of all of the previous research that has made these climate maps possible and give out some much deserved thanks. To begin, this image gives you a sense of how the thermal maps are made by integrating several streams of data for EnergyPlus:
(https://drive.google.com/file/d/0Bz2PwDvkjovJaTMtWDRHMExvLUk/view?usp=sharing)
To get you excited, this youtube playlist has a whole bunch of time-lapse thermal animations that a lot of you should enjoy:
https://www.youtube.com/playlist?list=PLruLh1AdY-Sj3ehUTSfKa1IHPSiuJU52A
To give a brief summary of what you are looking at in the playlist, there are two proposed designs for completely passive co-habitation spaces in New York and Los Angeles.
These diagrams explain the Los Angeles design:
(https://drive.google.com/file/d/0Bz2PwDvkjovJM0JkM0tLZ1kxUmc/view?usp=sharing)
And this video gives you and idea of how it thermally performs:
These diagrams explain the New York design:
(https://drive.google.com/file/d/0Bz2PwDvkjovJS1BZVVZiTWF4MXM/view?usp=sharing)
And this video shows you the thermal performance:
Now to credit all of the awesome people that have made the creation of these thermal maps possible:
1) As any HB user knows, the open source engines and libraries under the hood of HB are EnergyPlus and OpenStudio and the incredible thermal richness of these maps would not have been possible without these DoE teams creating such a robust modeler so a big credit is definitely due to them.
2) Many of the initial ideas for these thermal maps come from an MIT Masters thesis that was completed a few years ago by Amanda Webb called "cMap". Even though these cMaps were only taking into account surface temperature from E+, it was the viewing of her radiant temperature maps that initially touched-off the series of events that led to my thesis so a great credit is due to her. You can find her thesis here (http://dspace.mit.edu/handle/1721.1/72870).
3) Since the thesis of A. Webb, there were two key developments that made the high resolution of the current maps believable as a good approximation of the actual thermal environment of a building. The first is a PhD thesis by Alejandra Menchaca (also conducted here at MIT) that developed a computationally fast way of estimating sub-zone air temperature stratification. The method, which works simply by weighing the heat gain in a room against the incoming airflow was validated by many CFD simulations over the course of Alejandra's thesis. You can find here final thesis document here (http://dspace.mit.edu/handle/1721.1/74907).
4) The other main development since the A. Webb thesis that made the radiant map much more accurate is a fast means of estimating the radiant temperature increase felt by an occupant sitting in the sun. This method was developed by some awesome scientists at the UC Berkeley Center for the Built Environment (CBE) Including Tyler Hoyt, who has been particularly helpful to me by supporting the CBE's Github page. The original paper on this fast means of estimating the solar temperature delta can be found here (http://escholarship.org/uc/item/89m1h2dg) although they should have an official publication in a journal soon.
5) The ASHRAE comfort models under the hood of LB+HB all are derived from the javascript of the CBE comfort tool (http://smap.cbe.berkeley.edu/comforttool). A huge chunk of credit definitely goes to this group and I encourage any other researchers who are getting deep into comfort to check the code resources on their github page (https://github.com/CenterForTheBuiltEnvironment/comfort_tool).
6) And, last but not least, a huge share of credit is due to Mostapha and all members of the LB+HB community. It is because of resources and help that Mostapha initially gave me that I learned how to code in the first place and the knowledge of a community that would use the things that I developed was, by fa,r the biggest motivation throughout this thesis and all of my LB efforts.
Thank you all and stay awesome,
-Chris…
ssibili e facili da usare. Il corso parte dalle basi della programmazione di arduino fino ad arrivare all’interazione tra un oggetto fisico ed un imput informativo. tutor: Gianpiero Picerno Ceraso
Programma: I giorno Introduzione al Phisical Computing, input digitali e analogici, le basi del linguaggio di programmazione, esempi applicativi; led, pulsanti, fotorestistenze, servo motore, sensore di temperatura, di flessione, sensori di movimento, potenziometri.
II giorno Arduino ethernet, uso di un relè per carichi elevati, accelerometro, introduzione a Processing, interazione di Arduino e Processing, Introduzione a Grassoppher e Firefly e interazione con Arduino.
orario corso: 10:00 – 13:00 e 14:00 – 17:00 (pausa pranzo 13:00 – 14:00) costo: 150€ + IVA deadline: 13 marzo numero minimo di partecipanti: 3
Per iscrizioni scrivi a info@medaarch.com specificando nome, cognome, mail, recapito telefonico e il nome del corso al quali sei interessato. In seguito all’invio del modulo di pre-iscrizione, i partecipanti riceveranno una mail contenente tutte le specifiche di pagamento.
Per seguire il cluster su Arduino è necessario installare il software Arduino 1.0.5 al seguente linkhttp://arduino.cc/en/Main/Software#.Ux3hQj95MYE facendo attenzione a scaricare quello relativo al proprio sistema operativo, Windows 32 o 64 e Mac OS.
Software necessari solo per una parte del corso: Processing 2.1.1 https://processing.org/download/?processing
Rhino 5 http://www.rhino3d.com/it/download Grasshopper for Rhino5http://www.grasshopper3d.com/page/download-1Firefly http://fireflyexperiments.com/
Il cluster rientra in un fitto calendario di attività formative organizzate dalla Medaarch per lanno 2013-2014.…
occur more than once in the same list, and different elements with identical values can occur more than once. Also, a list may contain lack of elements, referred to as "nulls".
Sets. Strictly speaking a Set is a mathematical construct which adheres to a strict collection of rules and limitations. Basically, a Set is the same as a List, with the exception that it cannot contain the same element more than once, or indeed two or more different elements with the same values. You see, in mathematics there is no difference between a value and an instance of that value, they are the same thing. In programming however it is possible to store the number 7 in more than one spot in the RAM. Grasshopper does not enforce this rule very strongly though, you can use a lot of Set components on lists that have multiple occurrences of the same value. The big difference between Lists and Sets in Grasshopper is that Sets are only defined for simple data types that have trivial equality comparisons. Basically: booleans, integers, numbers, complex numbers, strings, points, vectors, colours and intervals. Lists can contain all kinds of data.
Strings. Strings are text. There's nothing more to it. I don't know why early programmers chose to call them strings, but I suppose it's a better description of the memory representation of them. Strings are essentially sequences of individual characters.
Trees. Trees are the way all data is stored in Grasshopper. Even when you only have a single item, it will still be stored in a tree. A tree is a sorted collection of lists, where each list is identified by a path. A specific path can only occur once in a tree, when you merge two trees together, lists with identical paths are appended to each other. Trees are an attempt to losslessly represent not just the data itself, but also the history of that data. Imagine you have 4 curves {A,B,C,D} and you divide each into 3 points {X,Y,Z}. Then, for each of those points you create a new line segment {X',Y',Z'} and then divide each of those line segments again into 5 points each {K,L,M,N,O}. The way data is stored in trees, it should be possible to figure out whether a point M belongs to X' or to Z', and whether that X' or Z' came from A, B, C or D. This is why paths are often quite long after a while, because they encode a lot of history.
Paths. A Path is nothing more than a list of integers. It's denoted using curly brackets and semi-colons: {A;B;...;Z}. A Path should never be empty {} or have negative integers {0;-1}, but it is certainly possible to create a path like this and it probably won't even crash Grasshopper. Paths are 'grown' by components that (potentially) create more than one output value for a single input value. For example Divide Curve. It creates N points for every single input curve. In cases like this a new integer is appended to the end of the path.
In the next release the Path logic in Grasshopper is somewhat different. I fixed a number of obscure bugs (hopefully without introducing new fresh bugs) and special cased certain operations to somewhat reduce the speed at which paths grow. This may well break files that rely on a specific tree layout, but I hope the temporary sacrifice will be worth the long-term benefits.
--
David Rutten
david@mcneel.com
Poprad, Slovakia…
lC_UtilEigenSystemSym (level 1) { Exception has been thrown by the target of an invocation. TargetInvocationException }
Object: MillC_UtilEigenSystemSym (level 2) { Could not load file or assembly 'Sawapansolversnet, Version=1.0.4490.29339, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. FileNotFoundException }
Object: MillC_Topostruct2D (level 1) { Exception has been thrown by the target of an invocation. TargetInvocationException }
Object: MillC_Topostruct2D (level 2) { Could not load file or assembly 'Sawapansolversnet, Version=1.0.4490.29339, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. FileNotFoundException }
Object: MillC_Topostruct3D (level 1) { Exception has been thrown by the target of an invocation. TargetInvocationException }
Object: MillC_Topostruct3D (level 2) { Could not load file or assembly 'Sawapansolversnet, Version=1.0.4490.29339, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. FileNotFoundException }
Object: MillC_FEASystem (level 1) { Exception has been thrown by the target of an invocation. TargetInvocationException }
Object: MillC_FEASystem (level 2) { Could not load file or assembly 'Sawapansolversnet, Version=1.0.4490.29339, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. FileNotFoundException }
Object: MillC_UtilFFT1D (level 1) { Exception has been thrown by the target of an invocation. TargetInvocationException }
Object: MillC_UtilFFT1D (level 2) { Could not load file or assembly 'Sawapansolversnet, Version=1.0.4490.29339, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. FileNotFoundException }
Object: MillC_UtilFFT2D (level 1) { Exception has been thrown by the target of an invocation. TargetInvocationException }
Object: MillC_UtilFFT2D (level 2) { Could not load file or assembly 'Sawapansolversnet, Version=1.0.4490.29339, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified. FileNotFoundException }
EDIT: Even with COFF disabled in GrasshopperDeveloperSettings this still happens (Thanks Jon)
Is millipede not compatible with Rhino version 5? Or is there a different .dll to use?
Having loaded some of the components:
I congratulate you on following Rutten's 3rd law of Grasshopper :)
Although I hope the Solver and especially the Stress lines get further refinement in order to differentiate them as I find it hard to read the small label at the bottom. Maybe the Chimney's can have different numbers 3 = 3D, 2 = 2D etc.
…
iece could be easily cut using the "plan" curve, the wall need extra attention and manual work to prepare.
This script attempts to automate the preparation of lasercutting curves with some control:
1) Height: The parameter is set using the "Name" property of the Rhino "plan" curve object. Number of storeys (e.g. 5) is to be entered in that field and the script will read it after you press F5 (recompute) in grasshopper. If the block models are not multiples of standardised storey height, you could set "Storey height" in grasshopper to 1 and set exact height to individual "plan" curves in Rhino.
(Special mention: This part of script including reading "Name" property in Rhino and auto-correcting curve direction is attributed to Victor Leung's Laser Cutting Tool for Block Models)
2) Mode of wrapping: The wall could either be "sitting" on the bottom plate and being completely covered by the top plate, or wrapping outside both the bottom and top plate. In either case, material thickness is taken into consideration and the finished model will remain the same size.
3) Extra height option: In preparing flat roof models, one may like to add extra height for parapet wall to make the model more appealing.
4) Easy picking up: Each individual piece has some uncut part (red lines for engrave) to hold itself in place after cutting. There is no need to use masking tape to stick. Individual pieces could be taken out when you are ready to use.
There are also known issues to this script:
1) At internal corners, the adjacent wall will be longer (in wrapping outside mode) or shorter (in sitting inside mode). You have to manual cut at this point.
2) It could not work with only one input curve. (Although it may be a stupid bug,) A dummy rectangle nearby could be created to make it work.
Enjoy,
Sa
Lasercutting Tool for Block Models (Fold and Wrap) by Sa Ng is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License. Based on a work at http://www.grasshopper3d.com/forum/topics/laser-cutting-tool-for-block-models.
…
/www.grasshopper3d.com/forum/topics/vb-vs-c-vs-python
http://www.grasshopper3d.com/forum/topics/which-programming-language-should-i-focus-on-vb-or-python
VB.Net and C#
VB.Net and C# both belong to the ".Net" family of languages, and the things you can do with them in Rhino/Grasshopper are nearly 100% equivalent. Grasshopper itself was written in a combination of VB.Net and C#. Some advantages/comments, in no particular order:
Performance - VB.Net and C# scripts tend to execute faster because they are "Just-in-time" compiled as opposed to interpreted.
Autocomplete - both VB.Net and C# have rich autocomplete functionality in their respective script editor components - significantly more so than the python editor. This can be helpful for beginners since you can "hunt" for methods and properties by just typing a "." after an object name and looking at the list of available methods/properties.
Native Component development - If you eventually want to develop GHA assemblies/plug-ins for grasshopper, as of Rhino 5 you will have to use one of these two languages. However, there are plans to introduce python-based plugins in Rhino 6. Even so, the resources around plug-in development are very rich in the C# and VB.Net environments (with c# seeming to be the more popular of the two).
"Strong Typing" - VB.net to some degree, and C# especially, are less "forgiving" languages than python - they require you to know about the data type of the objects you're operating on. This can sometimes result in more verbose code - as you explicitly convert from type to type - but it also promotes good programming practice and helps make errors more understandable.
.Net ecosystem - using a .Net language means you have access to the thousands of libraries publicly available, and the process of referencing these libraries and making use of them is comparatively straightforward relative to python. More on this in the following section.
Resources/Support - At least as of 2012, VB and C# turned up more results on this forum than python, and I think you'll find slightly more expert-level coders in those languages able to help you here.
Which one between the two? C# or VB.Net? - Personally, I greatly prefer C# - I find it to be cleaner and clearer to use. I also have some programming background in C++/Java/Processing so I found the "C family" approach to be more familiar. As David and Damian point out in some of the posts linked above, C# is more popular than either python or VB.net in the rest of the coding world. However, if you are learning without any prior programming experience you may find VB.net to be a bit easier to learn.
Python
Python is, without a doubt, a beautiful and elegant language, which is probably more than can be said for VB.Net/C#. It is very popular with beginner coders, and its syntax is more readily understandable.
Syntax - Python is beautiful to read and write. Its syntax is very clear and free of extraneous punctuation (for example the ";" line endings in c#). It has many very nice language features that make common tasks more concise, like its loop syntax, list comprehensions, list "map" and "filter."
Multiple ways to talk to Rhino/Grasshopper - Python enables two general approaches to interacting with the Rhino/Grasshopper environment: RhinoCommon and RhinoScriptSyntax. If you have prior experience with Rhinoscript, you may find RhinoScriptSyntax to be preferable - it adapts many of the methods you're familiar with to the python language, and simplifies some tasks. A word of caution though - working with Rhinoscriptsyntax can introduce a performance hit relative to RhinoCommon operations. C# and VB.net by contrast can only work with RhinoCommon.
"Goodies" - The Python environment in Grasshopper has some "special features" that the other languages lack. In particular, the "GHPythonLib" library enables the ability to call most Grasshopper components from within your code, and the ability to easily enable parallel processing to improve performance. (A word of caution though - these two features do not seem to "play well" with each other, there may be bugs causing memory leaks that result in increasingly worse performance with each execution).
Cross-Platform - Unlike C#/VB.net, Python can be used natively in Rhino for Windows and Rhino for Mac.
Direct scripting in Rhino - You can also use Python directly in the Rhino environment without the need for Grasshopper if you desire, using the Rhino Python editor.
IronPython / Ecosystem issues - one frustration / potential downside to working with Python for Rhino/GH is that though there is a vast, amazing ecosystem of external libraries for Python, getting these to install/work properly in the Rhino/GH environment can be a real pain - largely because the language is actually "IronPython," a version of python designed to work closely with the .Net ecosystem. Many popular libraries like numpy and scipy are very challenging to get working in Rhino/GH.
Scripting in other programs - Especially in the AEC industry, Python is a popular scripting language for other applications. Tools like Revit, Dynamo, Blender, and ArcGIS all offer their own Python scripting interface - so learning Python in Rhino/GH can give you a leg up in eventually scripting in these other programs.
Python's Stock is Rising - there are currently a number of efforts to improve the "status" of python within the Rhino/GH ecosystem. The python editor in Rhino 6 has a number of improvements, not least of which is the ability to "compile" add-ons for Grasshopper written in python. I'm sure Giulio can speak to other upcoming improvements.
I hope this summary helps you find the right option for you. Ultimately you can't go wrong; concepts from any of the available scripting languages will make it much easier to learn the next one. In my day to day work I use a combination of both C# and python, where appropriate, and I love them both.
I hope others will feel welcome to chime in on this FAQ and add their own thoughts about advantages/disadvantages of these various options! If you have time, read through some of the other posts linked to at the beginning - there's lots of additional great information there. …