(twice the amount of lines, it'll take twice as long).
If you nest two loops you're iterating over each line, and then you iterate again over each line. So when you now have twice as many lines, it takes four times as long O(N*N) or O(N²)
With an octree you can reduce the second iteration from O(N) to O(log N). The reason octrees are fast is because they allow you to quickly reject large amounts of lines in your set. Lines are no longer stored in a list, but rather in recursive spatial buckets. If we determine that a certain bucket is too far away to possibly yield any valid results, we can instantly skip all the lines in that buckets and any sub-buckets. If you're lucky, you can reject ~85% of the local data in every iteration, which means even large collections of lines are reduced to only a few potential candidates very quickly.
Thinking about this I'm actually not sure now whether lookup in my Tree3d class is O(log N) or O(sqrt N), but the basic principle holds. The reason the resulting algorithm is O(N * log N) is because the outer loop is still O(N) but the inner loop is now replaced with an O(log N) searcher, so you end up with O(N) * O(log N) = O(N log N)
At least that's how I think it works, computational theory has never been my strong suit.
--
David Rutten
david@mcneel.com
Poprad, Slovakia…
Added by David Rutten at 4:55pm on November 29, 2012
at 0.85m above the floor.
I copy paste from the Appendix E:Rights to Light of the book "Paul Littlefair, Site Layout Planning for Daylight and Sunlight, A good practice, BRE Press, p.60" which is the primary guide for evaluating the impact of new construction to the Rights to Light of the existing adjustment buildings:
"The accepted way of calculating the loss of light is to compute the sky factor at a series of points on the working plane. In dwellings, the working plane height is usually taken to be 0.85 m (two feet nine inches). The sky factor is the ratio of the illuminance directly received from a uniform sky at the point indoors, to the illuminance outdoors under an unobstructed hemisphere of this sky. No allowance is made for glass losses or light blocked by glazed bars and (usually) window frames; nor is reflected light included, either from interior surfaces or obstructions outside. Thus the sky factor is not the same as the CIE daylight factor (see Appendix C). The sky factor is often calculated using a Waldram diagram, but this is a different Waldram diagram to Figure B1 in Appendix B, which should not be used for this purpose."
Thought couldn't find the specific Waldram diagram for this case from the references, I assume contemporary analytical tools should exist to calculate it.
I used your Vertical Sky Component process and culled the mesh faces lower than 0.2% but I believe because of they type of the radiance analysis as you have explained it before (stochastic method) it doesn't create one continuous edge, as you can see in the attached image.
Thanks,
Dimitris…
of Space, 1984) and specified in (Turner A. , “Depthmap: A Program to Perform Visibility Graph Analysis, 2007), intuitively describe the difficulty of getting to other spaces from a certain space. In other words, the higher the entropy value, the more difficult it is to reach other spaces from that space and vice-versa. We compute the spatial entropy of the node as using the point depth set:
(11)
“The term is the maximum depth from vertex and is the frequency of point depth *d* from the vertex” (ibid). Technically, we compute it using the function below, which itself uses some outputs and by-products from previous calculations:
Algorithm 4: Entropy Computation
Given the graph (adjacency lists), Depths as List of List of integer, DepthMap as Dictionary of integer
Initialize Entropies as List(double)
For node as integer in range [0, |V|)
integer How_Many_of_D=0
double S_node=0
For depth as integer in range [1, Depths[node].Max()]
How_Many_of_D=DepthMap.Branch[(node,depth)].Count
double frequency= How_Many_of_D/|V|
S_node = S_node - frequency * Math.Log(frequency, 2)
Next
Entropies [node] = S_node
Next
…
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
adrid/
http://www.24studiolab.com/#/
or write to:
24studiolab@gmail.com
Course will be variable (during the weekend or during the week) depending on the convenience of the assistants.
COURSE PROGRAMME (spanish)*
Rendimiento formal / Estructural
Galápagos, algoritmos genéticos
Kangaroo physics
Optimización mediante fuerzas fisicas
Form Finding
Surface Relaxation
Edición avanzada de malla
Isosurface and fractals surface
Karamba
Rendimiento energetico
Heliotrope / Ghowl
Geolocalización
Geco
Kangaroo shape optimization
* COURSE PROGRAMME may vary depending on the demand of the assistant
…
Added by 24StudioLab at 2:10am on December 26, 2013
the optimizing process I am using Karamba+Galapagos.
Unfortunately I am getting some errors when calculating the maximum displacement of the bridge, using the Karamba “analyze” component.
95% of the times (when moving a slider), it goes well. I am getting deformations of 100-200mm as expected, and the deformed shape in the Rhino view looks good.But in the last 5%, I get unreliable deformations of 50000mm or more. What I dont understand about this is that the deformed shape in the Rhino view still looks normal. Another weird thing is if I move the slider away from the position and then back to the same position again, I suddenly get the result of 100-200mm. It seems more or less randomly when it gives the strange results.
The model has over time become pretty big. When moving a slider, calculation time is about 5 to 10 sec.Could this be the reason for the errors? Any other ideas about what goes wrong?
Thank you in advance for your answer.Attached please find the GH file.
Best regards Soeren…
umbrella of Urban Heat Island (UHI) and I am going to try to separate them out in order to give you a sense of the current capabilities in LB+HB.
1) UHI as defined as a recorded elevated air temperature in an urban area:
If you have access to epw files for both an urban area and a rural area, you can use Ladybug to visualize and deeply explore the differences between the two weather files. Ladybug is primarily a tool for weather file visualization and analysis and it can be very helpful for understanding the consequences of UHI on strategies for buildings or on comfort. This said, if you do not have both rural and urban recorded weather data or you want to generate your own weather files based on criteria about urban areas (as it sounds like you want to do), this definition might not be so helpful.
2) UHI defined by air elevated air temperature but viewed as a computer model-able phenomenon resulting primarily from urban canyon geometry, building materials, and (to a lesser degree) anthropogenic heat:
This definition seems to fit more with they type of thing that you are looking for but it is unfortunately very difficult and computationally intensive such that we do not currently have anything within Ladybug to do this right now. I can say that the state-of-the art for this type of modeling is an application called Town Energy Budget (TEB) and this is what all of the advanced UHI researches that I know use (http://www.cnrm.meteo.fr/surfex/spip.php?article7). Unfortunately for those trying to use it in professional practice, it can take a while to get comfortable with it and it currently runs exclusively on Linux (this does mean that it is open source, though, and that you can really get deep into the assumptions of the model). A couple years ago, a peer of mine translated almost all of TEB into Matlab language making it possible to run it on Windows if you have Matlab. He wrapped everything together into a tool called the Urban Weather Generator (UWG), which can take an epw file of a rural area and warp it to an urban area based on inputs that you give of building height, materials, vegetation, anthropogenic heat, etc. I would recommend looking into this for your project, although, bear in mind that is it not open source like the original TEB tool and that you may need to get a (very expensive) copy of MATLAB (http://urbanmicroclimate.scripts.mit.edu/uwg.php).
3) UHI as defined by a thermal satellite image of an urban area depicting an elevated average radiant environment that reaches a maximum a the city center and changes by land use:
This is the definition of UHI that I am most familiar with and was the basis of much of my past research. I feel that it is also a definition of UHI that is a bit more in line with where a lot of contemporary UHI research is headed, which is away from the notion of UHI as a macro-scale meteorological phenomena that is averaged as an air temperature over a huge area towards one that accepts that different land uses have different microclimates and (importantly) different radiant environments. While the air temperature difference between urban and rural areas usually does not change more than 1-4 C, the radiant environment can be very different (on the order of 10-15 C differences). The best way to understand UHI in this context is with Thermal satellite images, for which there is ha huge database of publicly available data on NASA's glovis website (http://glovis.usgs.gov/) or their ECHO website (http://reverb.echo.nasa.gov/reverb/#utf8=%E2%9C%93&spatial_map=satellite&spatial_type=rectangle). I tend to use thermal data from LANDSAT 5-8 and ASTER satellites in my research. Unfortunately, there is a lot f bad data with a lot of cloud cover mixed in with the really good stuff and it can take some time to find good images. Also, there aren't too many programs that read the GeoTiff file format that you download the data as. I know that ArcGIS will read it, a program called ENVI will read it (I think that the open source QGIS can also red it). I have plans to write a set of components to bring this type of data into Rhino and GH (I may get to it a few months down the line).
4) UHI as a computer model-able notion of "Urban Microclimate" with consideration of local differences and the local radiant environment:
This is where a lot of my research has lead and, thankfully, is an area that Honeybee can help you out a lot with. EnergyPlus simulations can output information on outside building surface temperatures and these can be very helpful in helping get a sense of the radiant environment around individual buildings. Right now, I am focusing just on using this data to fully model the indoor environments of buildings as you see in this video:
https://www.youtube.com/watch?v=fNylb42FPIc&list=UUc6HWbF4UtdKdjbZ2tvwiCQ
I have plans to move this methodology to the outdoors once I complete this initial application to the indoors. For now, you can use the "Surface result reader" and the "color surfaces based on EP result" components to get a sense of variation in the outside temperature of your buildings.
I hope that this helped,
-Chris
…
unity in Ukraine, which is orientated to contemporary architecture.
The results of CANactions will be published in ACC magazine (link), on the web-sites of “Architectural club” (link), AB "ZOTOV&CO" (www.zotov.com.ua),
Theme
Theme of CANactions 2009 is emergent design techniques.
This theme could include following architectural branches as Digital design, sustainable architecture and other sectors, which by the participants’ opinions, could be EMERGENT.???
Any architectural projects made earlier of specially for the CANactions’09 are allowed for submission.
Presentation
All the projects will be submitted in two phases:
Phase 1 – selection of 10-15 participants of CANactions.
Project has to be sent by e-mail to: (__) in PDF (not less then 300 dpi, not more then 10 Mb).
Phase 2 –the CANactions participants prepare 15-20 min presentation of their projects (screen projector, microphone) and materials for the exhibition in House of Architect, Kyiv. The project has to be presented by author. -> exhibition is the first architecture biennale
Presentation requirements: file should be composed in PDF format on A0 sheets, placed horizontal (not more then 1 sheets). This file should contain sufficient amount of the presentation graphic material, including text explanation up to 300 words.
The raster images should have printing definition not less then 300 dpi. It’s recommended to avoid solid black fillings, because the projects will be printed on ink-jet printer.
The presentation requirements could be changed after phase 1 results.
The presentation materials should be made in Ukrainian (or Russian) and English. Verbal part can be presented in any language.
Tarek Naga, Naga Studio, Los Angeles / USA (I can contact him - he will do it for free)
Awards
DIA (Dessau Institute of Architecture), Germany gives a prize: certificate for the education for 1 (2) semesters of Master-program in DIA for students and young architects (up to 30 years) from Ukraine. The decision about the prize winners will be made by selection board.
Guests presentations
- Daniel da Rocha DIA /Germany/ (flights, accommodation?). Theme: (scripting???)
- Aleksandr Kalachev DIA /Riussian Federation/, Tudor Cosmatu DIA /Romania/, Irina Bogdan DIA /Romania/ - "Parametrically Defined Urban Patterns".
- Grygorii Zotov DIA /Ukraine/ - “The Multicultural Columbarium”.
- Armen Menendian /USA/ - "Blending Parametric Methods With Traditional Design:
"The Danish Pavilion at Shanghai EXPO 2010".
Exhibitions
1. Projects of 10 (15) CANactions participants
2. other projects: Zotov+Co
Bollinger+Grohmann - structural eng.
the very many
C-Space Pavillon / alvin huang
ala _ amanda levete studio
anOtherArchitect
student work, Charles Walker, AA Unit Pavillon
Event schedule
Phase 1: 01.07.2009 – start of the CANactions 2009 and beginning of projects submission.
16.08.2009 - dead-line of the project submission of phase 1.
Phase 2: 17.08.2009 – announcement of the CANactions 2009 participants.
30.08.2009 – dead-line of submission of the CANactions 2009 exhibition materials.
14-26.09.2009 – exhibition of the CANactions 2009 projects in House of Architect, Kyiv.
25-26.09.2009 – CANactions 2009.
26.09.2009 - finnissage / announcement of competition winners for DIA study
Contacts: canactions2009@gmail.com…
Added by Grisha Zotov at 6:32am on August 10, 2009