(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
see in my bottom post image there is only one isocurve showing in U and V.
In Grasshopper there's no surface rebuild? Well, the same old Grasshopper Patch command will let you specify spans I guess, to make a surface from a planar curve, but it won't work for things with holes since they will just fill in!
You can recreate a surface painfully by untrimming, adding many UV points, rebuilding from those points, then retrimming with the original surface info, but the retrimming simply fails.
If you make a planar surface from a curve in Rhino, you end up with utterly no point editability:
No wonder my CreatePatch tests were a failure. The starting surface could not be distorted except in the extreme case of moving four corner points!
I have no idea how to successfully rebuild a surface akin to the Rhino rebuild command. It's great to be able to prototype in Grasshopper, but with Python I can rebuild easily ( http://4.rhino3d.com/5/rhinocommon/?topic=html/M_Rhino_Geometry_Surface_Rebuild.htm ;), so I guess I should start a collection, like peter, of little script components for prototyping with.…
Added by Nik Willmore at 6:18am on February 26, 2016
p; 3D Urban ModelingOn the topography subject I get the next message: "One or more boundaries may be outside the bounds of the topo dataset" I'm not sure if it's the .IMG file I'm loading since I found so many IMG files nearing my polyline area (Miami Lat:26 Lon:-81 aprox.) or maybe my polygon doesn't match the topo area? I have no idea why it isn't working :(On the Shapefile subject, haven't been able to find a Building Height SHP File, so far have downloaded around 8 SHP files which only contain Polylines, my solution is to meanwhile randomize Z heights, but of course this data is not "technically" correct.P.S.: I've already tried all example links and also the ones posted by you and Benjamin in this video.Been strugling last few days, hope you can help me, thanks in advance!!…
Simpsons episode were Bart goes into a mall and in the time he goes in and out of a shop all others have been turned into Starbucks.
I personally don't like it but you can't say they are crushing all competitors because, as far as i know, all owners of those software packages voluntarily sold their property for a good price. I would actually be more worried that an antitrust lawsuit was filed against Autodesk.
For example, this is what happened with Rockefeller's Standard Oil:
The antitrust case against Standard Oil also seems absurd because its share of the petroleum products market had actually dropped significantly over the years. From a high of 88 percent in 1890, Standard Oil's market share had fallen to 64 percent by 1911, the year in which the US Supreme Court reaffirmed the lower court finding that Standard Oil was guilty of monopolizing the petroleum products industry.[32]
The court argued, in essence, that Standard Oil was a "large" company with many divisions, and if those divisions were in reality separate companies, there would be more competition. The court made no mention at all of the industry's economic performance; of supposed predatory pricing; of whether industry output had been restrained, as monopoly theory holds; or of any other economic factors relevant to determining harm to consumers. The mere fact that Standard Oil had organized some thirty separate divisions under one consolidated management structure (a trust) was sufficient reason to label it a monopoly and force the company to break up into a number of smaller units.
To economists, "predatory pricing" is theoretical nonsense and has no empirical validity, either.
In other words, the organizational structure that was responsible for the company's great efficiencies and decades-long price cutting and product improving was seriously damaged. Standard Oil became much less efficient as a result, to the benefit of its less efficient rivals and to the detriment of consumers.
From: http://mises.org/daily/2317
(Beware, that site is very ideologically charged)…
points within the bounds of the site boundary and use each location as an attractor point controlling a variable at each point in the grid (radius of a circle/height of a cube/colour based on a gradient etc.).This would be based on proximity to the attractor points with the effect of each attractor point essentially scaled by the percentage associated with it. For example a location with 88% visitor rates would have a more dramatic effect than a location with 26% visitor rates.
I've had a bit of a play around but can't seem to get beyond the point of what is shown in basic point attractor tutorials online. I'm definitely a novice.
Here's how I figured it would be done:
1) Create a grid of source points within a boundary curve.
2) Select 18 pre-defined attractor points.
2) Measure the distance between the source points and the attractor points.
3) Invert this data so that variables increase with proximity rather than decrease.
4) Give each of the attractor points a strength value from 1-100% based on the visitor rates.
5) Use the scaled data to control a variable at each of the source points.
6) Create some way to control the drop-off rate of the effect from each point.
It is at step 3 that I get completely lost.
I hope my description is clear. Any help would be greatly appreciated,
Adam
…
Introduction to Grasshopper Videos by David Rutten.
Wondering how to get started with Grasshopper? Look no further. Spend an some time with the creator of Grasshopper, David Rutten, to learn the
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)
-----------------------------------------------------------------------
Participants will be given a certificate of participation at the end of the course.
-----------------------------------------------------------------------
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
ce issue with Rhino and shouldn't make an issue with EnergyPlus but just to have cleaner geometries, I untrimmed base surfaces so zones are closed brep now.
I also noticed that when you are adding multiple openings to a surface, the surface doesn't show-up in the output of createHBZoneFromHBSurfaces. The surfaces are there though and show up once you explode the zone! Again should be a tolerance issue for join. I need to take a closer look to both of these.
Also, in a number of the zones you had wall surfaces connected to createZoneFromHBSurfaces both before and after adding glazing. I removed parent surfaces so you don't end up having duplicate surfaces.
Back to adjacency which was your question, the issue happens since you have couple of zones with the same name so component was assuming them to be the same zone so it wouldn't solve the adjacency (Yes! it shouldn't. That was a bug which is fixed now). I changed the names and now it should find the surfaces that you are looking for.
Moreover, once you solve the adjacency, next solveAdjacency won't overwrite the BC unless you set remCurrentAdj to True.
Mostapha…
oCommonSDK, I modified a working C# component that does something similar (ReduceMesh, written by Andrew Heumann). Both scripts are attached.
Aside from changing the component name and eliminating the P parameter, I made two modifications to the script:1) changed line 87 from private void RunScript(Mesh M, double P, ref object A) to: private void RunScript(Mesh M, ref object A)2) changed line 93 from: Rhino.RhinoApp.RunScript("_-ReduceMesh _ReductionPercentage " + Convert.ToString(P) + " _Enter", false); to: Rhino.RhinoApp.RunScript("_-MatchMeshEdge " + " _Enter", false);When I run the ReduceMesh component, the mesh object I feed it gets baked, the ReduceMesh command is run, the temporary object is deleted, and the reduced mesh result is returned. (Thanks, Andrew).When I run the MatchMeshEdge component, the mesh object I feed it is baked, the MatchMeshEdge command is run, but the temporary object is not deleted and no result is returned. The runtime error reads: "Sequence contains no elements (line 0)". I have a feeling that the command line string I am handing to RunScript is incomplete. When I enter it manually on the Rhino command line I see that it wants a mesh and three parameters. Of course I can hit Enter to accept the default values, but when you invoke a command through RunScript do you have to supply all parameters regardless? Also, where would I find details on the argument types that the command wants? For example, the last parameter reads "RatchetMode=On" or "RatchetMode=Off". How do I know if the type is Bool or the literal string "On" or "Off"?I am a complete novice at this so any help you can provide would be greatly appreciated! …