(registrants will be able to re-watch it anytime) GOAL: understanding and managing surface continuity SOFTWARE: Rhinoceros, Grasshopper, Kangaroo 2 PREREQUISITES: basic experience of 3D modeling in Rhino LANGUAGE: English LENGTH: 160 minutes approximately TUTOR: Arturo Tedeschi
REGISTER HERE
One of the characteristics of contemporary design is a clear reduction of all visible connections, pursuing the idea of a seamless flow of curves and surfaces. From product design to automotive, from naval design to architecture’s envelope, understanding and managing surface continuity is an essential skill. The online webinar “Zebra” will introduce attendees to the notion of surface continuity in Rhino-Grasshopper. The lesson will cover mathematical aspect of curvature continuity, modeling strategies and practical examples. Contents are intended for users with basic knowledge of 3D modeling in Rhino. The webinar will be a fully interactive event hosted “live” but also available as a recorded video. Registrants will be able to re-watch it anytime. Zebra is part of our Parametric Vibrations webinar series. Tutor: Arturo Tedeschi. Language: English.
Main Topics:
NURBS representation
Notion of curvature for curves and surfaces
Curvature continuity for curves and surfaces: G0 – G3
Surface continuity in Rhino. Analysis tools: curvature analysis, Zebra, environmental map
Surface continuity in Rhino: tools, modeling strategies and tips for surface continuity.
Examples
Overview of continuity tools in Grasshopper
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t defined from the discussion of radiation exchange between urban surfaces and the sky in urban heat island research (See Oke's literature list below). It will be affected by the proportion of sky visible from a given calculation point on a surface (vertical or horizontal) as a result of the obstruction of urban geometry, but it is not entirely associated with the solid angle subtended by the visible sky patch/patches.
So, I think using "geometry way" to approximate Sky View Factor is not correct. Sky View Factor calculation shall be based on the first principle defining the concept: radiation exchange between urban surface and sky hemisphere:
(image extracted from Johnson, G. T., & Watson, 1984)
Therefore, I always refer to the following "theoretical" Sky View Factors calculated at the centre of an infinitely long street canyon with different Height-to-width ratios in Oke's original paper (1981) as the ultimate benchmark to validate different methods to calculate SVF:
So, I agree with Compagnon (2004) on the method he used to calculate SVF: a simple radiation (or illuminance) simulation using a uniform sky.
The following images are the results of the workflow I built in the procedural modeling software Houdini (using its python library) according to this principle by calling Radiance to do the simulation and calculation, and the SVF values calculated for different canyon H/W ratios (shown at the bottom of each image) are very close to the values shown in Oke's paper.
H/W=0.25, SVF=0.895
H/W=1, SVF=0.447
H/W=2, SVF=0.246
It seems that the Sky View Factor calculated from the viewAnalysis component in Ladybug is not aligned with Oke's result for a given H/W ration: (GH file attached)
According to the definition shown in this component, I assume the value calculated is the percentage of visible sky which is a geometric calculation (shooting evenly distributed rays from sensor point to the sky and calculate the ratio of rays not blocked by urban geometry?), i.e solid angle subtended by visible sky patches, and it is not aligned with the original radiation exchange definition of Sky View Factor.
I'd suggest to call this geometrically calculated ratio of visible sky "Sky Exposure Factor" which is "true" to its definition and way of calculation (see the paper on Sky Exposure Factor below) so as to avoid confusion with "The Sky View Factor based on radiation exchange" as discussed in urban climate literature.
Appreciate your comments and advice!
References:
SVF: definition based on first principle
Oke, T. R. (1981). Canyon geometry and the nocturnal urban heat island: comparison of scale model and field observations. Journal of Climatology, 1(3), 237-254.
Oke, T. R. (1987). Boundary layer climates (2nd ed.). London ; New York: Methuen.
Johnson, G. T., & Watson, I. D. (1984). The Determination of View-Factors in Urban Canyons. Journal of American Meteorological Society, 23, 329-335.
Watson, I. D., & Johnson, G. T. (1987). Graphical estimation of sky view-factors in urban environments. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 7(2), 193-197. doi: 10.1002/joc.3370070210
Papers on SVF calculation:
Brown, M. J., Grimmond, S., & Ratti, C. (2001). Comparison of Methodologies for Computing Sky View Factor in Urban Environments. Los Alamos, New Mexico, USA: Los Alamos National Laboratory.
SVF calculation based on first principle:
Compagnon, R. (2004). Solar and daylight availability in the urban fabric. Energy and Buildings, 36(4), 321-328.
paper on Sky Exposure Factor:
Zhang, J., Heng, C. K., Malone-Lee, L. C., Hii, D. J. C., Janssen, P., Leung, K. S., & Tan, B. K. (2012). Evaluating environmental implications of density: A comparative case study on the relationship between density, urban block typology and sky exposure. Automation in Construction, 22, 90-101. doi: 10.1016/j.autcon.2011.06.011
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what they really mean by that, as in what buttons to push, so I assume it's a Windows Path entry?
2.) Modify PATH
Add the install location on the path, this is usually: C:\Program File\IronPython 2.7
But on 64-bit Windows systems it is: C:\Program File (x86)\IronPython 2.7
As a check, open a Windows command prompt and go to a directory (which is not the above) and type:
> ipy -V PythonContext 2.7.0.40 on .NET 4.0.30319.225
Tutorial on setting a Windows environmental variable (path):
http://www.computerhope.com/issues/ch000549.htm
But this fails to point out that path contains many entries already separated by semicolons so if I merely add a new variable called "path" it's likely that I will destroy existing program function. There's no info on how to just tack on another entry, and the Windows 7 edit box doesn't even show the whole collection, but one item (!), so I copied the existing path into a text editor to see the whole collection successfully and added the C:\Program Files (x86)\IronPython 2.7 entry after an added semicolon, correcting for an Enthought page typo of no 's' on the end of "Program Files". I also checked the others and many pointed to old missing directories so I deleted those entries.
...and the test fails and "ipy" is not recognized as a command, even though the path now shows up using "path" in the Windows CMD window, that is if I copy all by right clicking and pasting the stuff into a text editor to really view it all. I can run it from the source directory just fine.
The rabbit hole was indeed deep. Using the Task Manager (control-alt-delete) to kill Explorer and then Run in the menu to restart "Explorer," along with restarting the Windows CMD window however, worked. I can now invoke Iron Python ("ipy") via command line from any directory. For the "path" I edited path in the System Variables and not the User Variables. No, you don't have to type that whole crazy line above just to test the path variable, just "ipy" (and control-Z to quite IronPython) in the CMD window invoked by typing "cmd" into the Start menu search box.
From the CMD line this step did work fine:
3.) ironpkg
Bootstrap ironpkg, which is a package install manager for binary (egg based) Python packages. Download ironpkg-1.0.0.py and type:
> ipy ironpkg-1.0.0.py --install
Now the ironpkg command should be available:
> ironpkg -h(some useful help text is displayed here)
But of course Step 4 fails, giving pages of what seem to be error messages;
C:\Users\Nik>ironpkg scipy
Traceback (most recent call last):
File "C:\Program Files (x86)\IronPython 2.7\lib\site-packages\enstaller\utils.
py", line 92, in write_data_from_url
File "C:\Program Files (x86)\IronPython 2.7\Lib\urllib2.py", line 126, in urlo
pen
File "C:\Program Files (x86)\IronPython 2.7\Lib\urllib2.py", line 397, in open
File "C:\Program Files (x86)\IronPython 2.7\Lib\urllib2.py", line 509, in http
_response
...
Why can't I just download Numpy as a normal file and thus also have it easy for other users to install it when they use my scripts? This is just crazy and lazy. The Enthought developer has turned this into a computer game, with a missing registration link and then the last step spits out errors with utterly no information on how to fix it manually.
This Step 4 error is covered here:
http://discourse.mcneel.com/t/trying-to-import-numpy-in-rhino-python-but-im-getting-this-error-cannot-import-multiarray-from-numpy-core/12912/16…
Added by Nik Willmore at 2:36pm on October 11, 2015
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…
ou will see all of the available components on a ribbon at once so there is no need to keep clicking drop down menus.
It's all about discoverability with GH. What if you're a beginner and don't know about the Create Facility (dbl click canvas) how can you find Extr?
Even if you hover over every component or use the drop down lists you will not see the name Extr appear anywhere.
Sure it makes sense that Extr is short for Extrude but it's also the Nick Name of Extrude to Point component
So you can easily miss the fact that one has a Distance Input verses a Point Input.
I think I made the move to Icons around about the move from version 0.5 to 0.6, possibly before. I initially thought that I would go back to text because I loved the mono chromatic look of the text but I soon realised that Icons were the way forward. The greatest benefit is speed. You don't need to digest and decipher every component (which is written 90 degrees to the norm).
I'm not saying you should move to Icons forthwith but at least consider that once you have a better knowledge and understanding of GH, Icons will set you free.
My top ten tips that I would highly recommend to anyone wanting to better themselves with GH.
1) Turn on Draw Icons
2) Turn on Draw Fancy Wires
3) Turn on Obscure Components
4) Use the Create Facility like a Command Line eg "Slider=-1<0.75<2" or "Shiftlist=-1"
5) Use Component Aliases to customise your use of the Create Facility eg giving the Point XYZ component an alias of XYZ will bring it up as the first option on the Create Facility as opposed to the other possibilities.
6) Try to answer other people's questions even if it's not relevant to your own area. By looking into solving a problem outside of your comfort zone and then posting your results it is very rewarding but it also lets you see the other approaches that get posted in a new light.
7) Take the time to understand Data/Path structures.
8) Buy a second monitor - There is nothing that can compare to real estate when working in Grasshopper.
9) Read Rajaa Issa's Essential Mathematics
10) Pick a panel in a tab on the ribbon and get to know every component inside and out and then move on. Start with the Sets Tab > List Panel…
http://www.pilkington.com/) dominates the planar market. Charges "around" 1K Euros per m2 for a "plain" system. Personally in bespoke projects I design my own stuff but due to economies of scale ... they cost a bit more (but they look far more sexier, he he) . On the other hand only in a bespoke project I could dare to suggest such a solution (for a large scale building we are talking lots and lots of dollars).
3. Several scales below (aesthetics) you can find static alu systems (either structural or semi-structural):
Or hinged systems (either structural or semi-structural) capable to adapt in contemporary double curvature facades/roofs/envelopes/cats/dogs etc etc ... pioneered worldwide many years ago by my best friend Stefanos Tampakakis (everybody in UAE knows that genius man: http://www.alustet.gr/company.html):
4. With the exception of some paranoid things that Guru Stefanos does for Zaha these days we are talking about planar "facets" (obviously a triangle is such a planar facet). The current trend is: the more edges the better (humans excel in vanity matters). But achieving planarity in, say, quads (like yours) it adds another "restriction" on what you are doing. Until recently Evolute Tools Pro was the only answer. But right now ... well let's say that in short time you'll be greatly surprised by some WOW things in this Noble Forum, he he.
5. MERO (and obviously custom systems) can adapt (at almost no extra charge) in anything imaginable. But in a bespoke building ... well.. you know ultra rich people: they don't want MERO anymore since "everybody" does MERO solutions. Vanity, what else?
6. Smart Glass would become a must in the years to come: Eco-Architecture MUST dominate everything you do. On the other hand spending millions to do some extra WOW stuff (Vanity) ... it doesn't look to me very Eco-Friendly/Whatever ... but let's pretend so, he he.
7. I'm Architect but a bit different from the norm: for instance I smoke cigars (highly politically incorrect stuff) I always talk openly (ditto) and I ride lethal bikes (ditto).
may the Force (as always the Dark Option) be with you: go out there and kill them all.
best, Peter
…
Ladybug + Honeybee:
(Follow steps 0-4 for basic functionality and 0-9 for full functionality)
0. If you have an old version of LB+HB, download the file here (https://app.box.com/s/ds96em9l6stxpcw8kgtf)
and open it in Grasshopper to remove your old Ladybug and Honeybee version.
1. Make sure that you have a working copy of both Rhino and Grasshopper installed.
2. Open Rhino and type "Grasshopper" into the command line (without quotations). Wait for grasshopper to load.
3. Install GHPython 0.6.0.3 by downloading the file at this link (http://www.food4rhino.com/project/ghpython?ufh) and
drag the .gha file onto the Grasshopper canvas.
4. Select and drag all of the userObject files (downloaded with this instructions file) onto your Grasshopper canvas.
You should see Ladybug and Honeybee appear as tabs on the grasshopper tool bar.
(If you are reading this instruction on github you can download them from http://www.food4rhino.com/project/ladybug-honeybee)
5. Restart Rhino and Grasshopper. You now have a fully-functioning Ladybug. For Honeybee, continue to the following:
6. Install Radiance to C:\Radiance by downloading it from this link (https://github.com/NREL/Radiance/releases/download/4.2.2/radiance-4.2.2-win32.exe) and running the exe.
7. Install Daysim 4.0 for Windows to C:\DAYSIM by downloading it at this link (http://daysim.ning.com/page/download) and running the exe.
8. Install EnergyPlus 8.1 to C:\EnergyPlusV8-1-0 by going to the DOE website (http://apps1.eere.energy.gov/buildings/energyplus/energyplus_download.cfm), making an account, going to "download older
versions of EnergyPlus, selecting 8.1 and running the exe.
9. Copy falsecolor2.exe (http://pyrat.googlecode.com/files/falsecolor2.exe) and evalglare.exe (http://www.ise.fraunhofer.de/en/downloads-englisch/software/evalglare_windows.zip/at_download/file) to C:\Radiance\bin
10. You now have a fully-working version of Ladybug + Honeybee. Get started visualizing weather data with these video tutorials (https://www.youtube.com/playlist?list=PLruLh1AdY-Sj_XGz3kzHUoWmpWDXNep1O).
After I've done all the above I followed this video
https://vimeo.com/96155674
And everything works well.
…
nted" in space (at instance definition creation phase): indicates the obvious fact that if garbage in > garbage out (try it).
2. Load the GH thing. Task for you: Using Named Views locate the points of interest as described further and make a suitable view. That way you can navigate rather easily around (hope dies last).
3. Your attractors are controlled from here:
The slider in blue picks some attractor to play with. You can use this while the K2 is running.
4. Don't change anything here (think of it as a black box: who cares how it works? nobody actually):
5. Enable the other "black box": job done your real-life stuff is placed:
6. Enable the solver: your "real-life" things start to bounce around:
7. Go there are play with the slider. A different attractor yields an other solution:
8. With real-life things in place if you disable the C# ... they are instantly deleted and you are back in lines/points and the likes:
9. Either with instance definitions or Lines/points change ... er ... hmm ... these "simple" parameters and discover the truth out there:
10. Since these are a "few" and they affect the simulation with a variety of ways ... we need a "self calibrating" system: some mini big Brother that does the job for us. Kinda like applying safely the brakes when it rains (I hate ABS mind).
NOTE: the rod with springs requires some additional code ,more (that deals with NESTED instance definitions) in order to (b) bounce as a whole and at the same time (b) elongates or shrinks a bit.
More soon.
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ng/702/30
EDIT: DK2 works, not with positional tracking yet (14/09/15)
Source is here:
https://github.com/provolot/RhinoRift
Steps:
1) Download these files (also attached below):
https://github.com/provolot/oculus-grasshopper/raw/master/oculus-grasshopper_v0.4.ghx
https://github.com/provolot/oculus-grasshopper/raw/master/OpenTrackRiftGrasshopperUDP.ini
https://github.com/provolot/oculus-grasshopper/raw/master/oculus-grasshopper-test_v0.1.3dm
2) Download OpenTrack - http://ananke.laggy.pk/opentrack/, and setup/install. Once installed, double-click to open.
3) In OpenTrack, load the 'OpenTrackRiftGrasshopperUDP.ini' profile. Click the 'Start' button and move your Rift around - make sure that it looks like the Yaw/Pitch/Roll data is being sent. TX/TY/TZ will all be 0, as Oculus doesn't have absolute positioning data.
4) In Rhino, open the test 3dm. You'll notice that there are two viewports - called 'LeftEye' and 'RightEye'. These have been placed to mimic where the screens should be for the Oculus Rift --- but only when Rhino is in fullscreen mode, with the command 'Fullscreen'. The placement needs to be tweaked, but should work.
If you want to use your own model, you can load your own .3dm file in Rhino, then you can right-click on the viewport name, and go to Viewport Layout > Read from File. If you then load my test file, Rhino should open my two viewports, sized correctly, onto your model.
The placement of these viewports need to be tweaked; if you find a better viewport layout, upload an empty Rhino file with your viewports, and we can share eye-layout 'templates'!
5) In Grasshopper, open the .ghx definition. Everything that is multiple-grouped is a value that can be changed. Two things here:
- IPD: Set this and convert it to the proper units for your model.
- Left/right viewport names. In this case, leave this as-is, since you're using my example file.
6) Turn on the Grasshopper Timer, if it isn't on already.
7) In the GH definition, toggle 'SyncEyes' to be True. Then, in the left viewport, try orbiting around with the mouse. The 'RightEye' viewport should move around as well, pretty much simultaneously.
8) In OpenTrack, click 'Start', then toggle 'ReadUDP' to be True. You should see the 'OpenTrackInfo' panel fill with data that's constantly changing.
9) Move around the landscape with your camera, and when you set on a starting view that's ideal, click the triangle of the Data Dam component to 'store' the data.
10) Finally, toggle 'OculusMove' to be true. If all works correctly, both viewports should move based on the Rift's movement.
Let me know if you have any problems!
Cheers,
Dan…
Added by Dan Taeyoung at 11:47pm on December 10, 2013