well, very similar input data must result in wildly different hashes. For example, imagine we have an algorithm which computes hashes of text, and the hashes it computes are all numbers between 0 and 999. We then apply this algorithm to a piece of text:
"When Spring comes back with rustling shade" = 385
So far so good. Now imagine we change the text slightly, for example by removing a single "l":
"When Spring comes back with rusting shade" = 973
Minor change -> very different hash. There are of course way more unique texts than there are numbers between 0 and 999. This must therefore mean that a lot of text will result in the same hash. For example "When Spring brings back blue days and fair." may also result in a hash of 385. Because of the pigeonhole principle, there is nothing to be done about this.
Now for the tricky bit. Hashes are often used to validate executable code. Say your friend James at MI6 sends you a small program that will allow you to eavesdrop on Angela Merkel, and -over the phone- he tells you the hashcode for that application. You can then hash the application yourself, verify that it indeed results in the same hashcode and then you know you can trust the executable.
But now Jack from the FBI intercepts the email and adds a few sneaky lines of code to the original application allowing him to determine from your internet search history with up to 95% accuracy whether you like extra cheese on your pizza. The application has now been tampered with, it can no longer be trusted and you should be able to figure this out as it will no longer result in the same hash code.
But wait! Some hashing algorithms are more secure than others. MD5 is now officially considered to be 'hacked' and it is no longer recommended for doing naughty spying. Specifically, Jack will be able to inject his own code in such a way that it does not result in a different hash. Instead, the SHA family of hashers are to be used, as it is not yet known how to trick these hashers.
This is where the problem comes in, because apparently the US government has forcefully disabled the use of MD5 for all purposes. This is a shame because I use it to quickly compare bitmap icons for identicalness so I only have to store an icon in memory once. There is no security hole due to this, because I'm not hashing secure data. MD5 is somewhat faster than SHA, and since I have to hash several hundred icons on Grasshopper start, I opted for the faster one.
(Very) long story short; you're hosed. Grasshopper uses MD5; USgov does not like; Grasshopper does not run on USgov computers.
I'll do some testing to see if I can switch to SHA and then we can see whether or not that solves the problem. This however will take a while as I'm going on a business trip next week and have yet to prepare my presentations.
--
David Rutten
david@mcneel.com…
Added by David Rutten at 12:06pm on March 31, 2014
ss lots of questions,Hope guys show me some more different ways to figure out thoes kinds of problems,Thanks.
That is a construction project,the balconies should be overhang between 1 to 3 meters.
Program A is a patten consist of increasing balconies as the floors get upper.(In the picture is 29 at the first floor and ended with 2 more balconies for each floor, )Each part for a different floor,the twelfth floor have 29+(12-1)*2=51 balconies.
Questions From A,
A1:How to use the {(series)} to creat this atrium,As the floors increase the number of the balconies change by arithmetic progression.
A2:How to control the angle of the balconies,both the angle with floor and the balconies ending part.
Program B is use line to shape the commercial atrium,program A is more small pieces of rectangles.The {(TweenCrv)} command.
Questions From B,
B1:How to draw random points between the 1 to 3 meters region of the balcony,And those point form a shape also belongs to that region.
B2:Use a curve or other ways to control the changing speed of each floors' balcony.Right now the balcony is a Linear change.
Thanks for your Help.
Q1:Is there a way in Grasshopper to control the model to Modulus,less different unit parts to build such a Atrium.(For Exanple,only use 900mm and 600mm two different width of the Glass railings to bulid the model A OR B)…
y using the Honeybee_Update Honeybee component.
The video below (best viewed in full-screen mode) provides an idea of what these components are capable of being used for:
The video below shows how these components can be used in an existing Honeybee project (for additional links please open this video in youtube):
I have uploaded two examples as Hydra files that show how these components can be used for grid-point and image-based simulations:
Example1 : Grid Point Calculations
Example2: Image based simulation
Finally, a more esoteric application is demonstrated in this video:
These components are still in the beta-testing stage. Some of the limitations of the components are:
1. Only Type C photometry IES files are supported at present.
2. Rhino is likely to get sluggish if there are too many luminaires (i.e. light fixtures) present in a scene.
3. Due to the spectral limitations of the ray-tracing software (RADIANCE), simulations involving color mixing might not be physically realizable.
Additional details about photometric and spectral calculations are probably an overkill for this forum. However, I'd be glad to answer any related questions. Please report any bugs or request new features either on this forum or on Github.
Mostapha, Leland Curtis, Reinhardt Swart and Dr. Richard Mistrick provided valuable inputs during the development of these components.
Thanks,
Sarith
Update 16th January 2017:
An example with some new components and bug fixes since the initial release announcement can be found here
…
te some cut sheets, but not to optmize material, rather define some cut lines. Everything that I am cutting is made of planar wood elements, but there are very specific geometries (mostly straight lines) and I have to put tolerances and radiasas at the corners in order to cut on the cnc mill. Spending time to figure out how to automate is necessary, but I am stuck!
One thing the definition is doing is taking my brep modeled components in rhino and makking them into 2d close curves and laying them side by side. It works...not ideal as its not layed out in a sheet, but that is not the most important part.
Another particular problem is that you will see some notches in the curves, which other pieces will slip into, so different slots need different specific offsets (making them larger) as a toelrance to allow for material play. This I don't even know how to set up so maybe it will just have to wait.
THE MAIN QUESTION, and super important would be, LIFESAVER:
At all 'inward' corners...which I think will always mean concave corners (most are 90 degrees, but are within to sides, instead of a corner sticking out). I'm sure its obviousy, but the reason being the outward corners a circular dril bit can cut, but inward ones need an arc profile extended beyond where the corner of the other piece will fit into. The drill bit i am using is 6mm, so 6mm diamters arcs is what i'm working with.
I have managed to put such an arc at every vertices of each cut piece. The problem being some stick outward isntead of cutting into the piece. So each one needs to be orieneted correctly. Ideally they would also only draw into inward corners, but I can always delete them out. I think maybe I am missing a more logical mathematical way of defining?
For these geometries it is not very important which side the half circle arc in on in the inward corners, but I also have some geometries that I will have to control where the circles face according to the rest of the cut piece.
The cutouts in the middle of the pieces that are curves do not need such corners obviously.
The picture is an example drawn
I hope this isn't too specific and long. in general though automating fabrication, and controling pracitcal math and orientation problems like this is itnersting to me!
THANKS…
perienced with grasshopper, but so far I've managed to combine the following:
Giulio Piacentino's "Catenary arch from height" script
Pirouz Nourian's "Mobius" script (Obtained from a friend)
End Result:
Here's where I'm stuck: I want the mobius twist to revolve around the midpoint of the arch, but the script uses the input values to determine the endpoints, resulting in a weird sinuous shape when viewed from above. Also, the secondary end points (generated by the mobius script, determining the width of the surface) are generated by default along the z axis, resulting in an arch that only touches the "ground" at two points. I attempted to work around this issue by trying to force the zHeight parameter to correspond with the y axis (thus rotating the arch 90 degrees so it would lay "flat"), but the script interprets the third point as a value and not as an actual point to bisect. I thought this might be an issue with the C# component that I obtained from Giulio Piacentino's script, so I attempted to tinker around with the source code. Unfortunately, I'm not fluent in C# so I only managed to mess everything up (I've since recovered the code from the cache). Anybody got some ideas? -BC …
onsidered period.
Even if the end of July for the mediterranean climate is not the best period to perform an adaptive comfort analysis (it's just a pretest to define a LB model) I want to refine the Adaptive comfort Chart (AC) by changing the external air temperature data imported from the .epw file with that of monitored data as reported here below:
Where the monitored ext air temperature are in this form (green panel below):
I have used the comfortPar component to set the following parameters:
Adaptive chart as defined by EN 15251
90% of occupants comfortable
the prevailing outdoor temperature from a weighted running mean of the last week
fully conditioned space (even if it is not properly in line with AC as already discussed)
The question is this: the AC component could correctly apply the code below if there is only a list of external temperature data for a restricted period (without indication about the limits of this period) and not for an entire year?
else: #Calculate a running mean temperature. alpha = 0.8 divisor = 1 + alpha + math.pow(alpha,2) + math.pow(alpha,3) + math.pow(alpha,4) + math.pow(alpha,5) dividend = (sum(_prevailingOutdoorTemp[-24:-1] + [_prevailingOutdoorTemp[-1]])/24) + (alpha*(sum(_prevailingOutdoorTemp[-48:-24])/24)) + (math.pow(alpha,2)*(sum(_prevailingOutdoorTemp[-72:-48])/24)) + (math.pow(alpha,3)*(sum(_prevailingOutdoorTemp[-96:-72])/24)) + (math.pow(alpha,4)*(sum(_prevailingOutdoorTemp[-120:-96])/24)) + (math.pow(alpha,5)*(sum(_prevailingOutdoorTemp[-144:-120])/24)) startingTemp = dividend/divisor if startingTemp < 10: coldTimes.append(0) outdoorTemp = _prevailingOutdoorTemp[7:] startingMean = sum(outdoorTemp[:24])/24 dailyRunMeans = [startingTemp] dailyMeans = [startingMean] prevailTemp.extend(duplicateData([startingTemp], 24)) startHour = 24
…
try now to integrate Geco in an interdisciplinary architectural engineering studio: hoping we can show you some nice applications of your tool, I'll keep you update and sending now details by e-mail. Here the file (very welcome to be shared). It most probably contais trivial errors by me, thanks for helping and giving some tip! Gr. Michela
FILE:
Ok, right, I see the outputs update correctly. Origin of problems must be in some different mistake I do:
- Incident radiation: I am not sure I understand what is going on: why I get so many 'not a number' ? (The Galapagos report is full of NaNs).
Bio-Diversity: 0.887 Genome[0], Fitness=NaN, Genes [89% · 44%] { Record: Too many fitness values supplied } ...
Genome[7], Fitness=NaN, Genes [74%] { Record: No fitness value was supplied } ....
Genome[9], Fitness=NaN, Genes [37% · 11%] { Record: Genome was mutated to avoid collision Record: Too many fitness values supplied }
- Daylight calculations: the geometry accumulates withouth deleting the previous models. As a consequance, results almost do not change after few varations (so, outputs get updated but do not vary). In current daylight definition: the first object being imported is the one where the grid has to fit; its setting makes it cancelling all the other objects during import. All the others, do not delete anything when imported. When running loops (manual or GA) that vary parameters, the entire geometry do not get cancelled - so I guess the loop does not pass back by the cancelling step, but imports only the geometry which has been varied by the parameters using the setting of that import component only? I will then try again by changing the order of the operations, but if you have specfic tips, let me know.
THANKS!
…
troducción a su plugin de modelado paramétrico, Grasshopper.
Con este tipo de herramientas podemos pensar formas más allá de las cajas para diseñar, porque seremos capaces controlar con total rigor geometrías muy complejas.
En el siguiente video, podemos ver un ejemplo realizado durante un curso impartido anteriormente en Madrid por el profesor, Francisco Tabanera, en el que se realiza una interpretación del proyecto de BIG para la Biblioteca Nacional de Kazajstán.
<a title="Interpretación de la Biblioteca Naiconal de Kazakstan, de BIG" href="http://www.youtube.com/watch?v=YLldO-SxgPw" target="_blank"></a>
A lo largo del curso se realizarán diferentes ejemplos que podrán ser realizados por todos los asistentes, ya que no es necesario ningún conocimiento previo para su seguimiento.
El curso se desarrollará en las oficinas de Arquitecton en Barcelona con el siguiente horario:
HORARIO
Sábado 1 de Marzo
De 9.30 a 13.30h.
Sábado 1 de Marzo
De 15.30 a 19.30h.
El curso está planteado para un máximo de 9 alumnos, para conseguir el máximo aprovechamiento posible por parte de los mismos.
El curso tiene un precio de 90€. Estudiantes y desempleados tienen un descuento del 10%. Es posible asegurarte una plaza con un primer pago de 25€ a modo de reserva.
Apúntate aquí…
next level.
This Parametric Design course will provide the participants with the necessary knowledge and ability to use Grasshopper, a free visual programming plugin in Rhinoceros; you will be guided through a series of hands-on exercises that highlight NURBS modeling and its concepts. We will introduce Grasshopper as a graphical algorithm editor tightly integrated with Rhino’s 3D modeling tools. You will also learn how Rhino is used to render models for visualization, translate 3D models for prototyping, and export 3D models into 2D CAD or graphics programs.
English is the course main language.
Location: Düsseldorf city center
Registration and buying Tickets
www.digitalparametrics.eventbrite.de
Course Calendar:
4 Days 6 hours each
Total duration 24h
2 weekends
Date:
Sat. 17 - Sun. 18 June
Sat. 24 - Sun. 25 June
10:00 - 17:00
Getting Started in Rhino. 2 days (17 - 18 June)
Getting Started in Grasshopper. 2 days (24 - 25 June)
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Participants will be given a certificate of participation at the end of the course.
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Course fees:
Professionals: 600€ (excl. MwSt.) Students: 500€ (excl. MwSt.) Students need to provide: Copy of current student ID or proof of student enrollment at University/School.
Group discounts:
Group of 3 professionals: 3x500 = 1500€ (excl. MwSt.)
Group of 3 Students: 3x400 = 1200€ (excl. MwSt.)
Participants are kindly asked to bring their own laptops and have pre-installed Rhino + Grasshopper.
Useful Resources:
Rhinoceros Installation (90 days full version trial available): http://www.rhino3d.com/download
Rhinoceros for Mac (includes Grasshopper) http://www.rhino3d.com/download/rhino-for-mac/5/wip
Grasshopper Free Installation: http://www.grasshopper3d.com/page/download-1
Grasshopper Free Plugins: http://www.food4rhino.com/app/lunchbox http://www.giuliopiacentino.com/weaverbird
Main Tutor:
Rihan
M.A. Dipl.Ing. Architect
Architect at RKW Architektur + Düsseldorf
For any questions about the course, please email: info@immersive-studio.com…
ll geometry.
The difference with programs like Inventor is that they are made for production, regardless of the fabrication method. I won't go into detail about that, and instead focus on the modeling process.
In this little model, the starting point actually is a bit obvious, the foundation.
The only contents in the 3dm file are 27 lines. These indicate the location of each footing, and the direction of the tilt of each column. Everything else is defined in GH with the use of numbers as input parameters.
Needless to say, instead of those lines you could obviously generate lines and control the number of columns and panels, hence establish their layout, with any algorithmic or non-algorithmic criteria you please. That marks a major difference between GH and Inventor.
You can generate geometry with Inventor via scripting/customization (beyond iLogic), with transient graphics for visual feedback similar to GH's red-default previews. However Inventor's modeling functions are not set to input and output data trees. I won't go into detail on that, but suffice to say that the data tree associativity of GH was for me the first major difference I noticed. I've used other apps with node diagram interfaces like digital fusion for non-linear video editing since the late 90's, so the canvas did not call my attention when I first started using GH.
Anyways, here's a screen capture of the foundational lines:
In the first group of components, the centerlines of the rear columns are modeled:
And the locations in elevation for connection points are set. Those elevations were just numbers I copied from Excel, but you can obviously control that any way you please. I was just trying to model this quickly.
The same was done for the rear columns:
The above, believe it or not, took me the first 5 hours to get.
Here's a screen capture of what the model and definition looked like after 4 hours, not much:
If you're interested, next post I can get into the sketching part you mentioned, which is a bit cumbersome with GH, but not really.
I wouldn't say that using GH to do this little model was cumbersome, it just needed some thinking at the beginning. You do similar initial thinking when working with a feature-based modeler.…
Added by Santiago Diaz at 12:44am on February 24, 2011