(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.
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David Rutten
david@mcneel.com
Poprad, Slovakia…
Added by David Rutten at 4:55pm on November 29, 2012
ions are probably reflective of the prevailing humidity conditions (I just had a chat about this with my advisor, who incidentally also happens to be on the committee for LM-83).
The Tregenza sky patches considered in daylighting calculations don't do a good job of incorporating the correct size of the sun into calculations. In the figure below, the sun on the right is the one considered for calculations in Daysim. You can get a more accurate answer by considering a more discretized sky, however, I am not aware if that is possible with Daysim (and therefore HB) right now. Therefore, your direct sun calculations are likely to be off somewhat depending on how much of it there is(I'd say overestimated).
The calculations with humid sky, which are on account of the sky itself (and not the sun alone) are likely to be more relevant.
Regarding your questions about studying weathering effects with LB/HB, I have no idea as that is something that I haven't looked into before. I am sure someone else on this list has a more informed opinion on this issue than I do.
Your project, and your approach to it, seems really interesting and I am glad to be having this discussion :).
Sarith
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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
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button to generate such complicated and unruled geometry. Seriously, if you don't understand a geometry, how can you solve the structural needs and the bloody fabrication. Giant fast prototyping machines doesn't exist!
In a era where ressources and energy is getting scarce, I don't understand this trend of fancy no sence look like organic buildings. They just look organic in our human perception. Nature builds things with define physical and biochemicals rules, and this is why when they grow, they look like that. You should study Frei Otto publication from the 80's.. the IL publications. They were using physical models to generate physical structures that would be build in the physical world. Computers and softwares are dangerous as we distach from reality.
We put all this effort to generate these fancy forms, but no brain is put in structural optimization, energy efficiency (for instance in relation with the sun, or other natural elements)
IT technology goes faster than the time we have to reflect about it. (not talking about the technics).
As Frei Otto told me personally in our last discussion (talking about philosophy and architecture): " We have to define the OPEN QUESTIONS. Once these questions will be defined, you'll get answers".
I think we are getting to a question here: " How to use this technology to solve problems in Architecture?" Before that " What are the real problems in architecture?"
Maybe David should make a component for that? For instance, a button that could solve the loging and infrastructure problems for these millions of people living in the slums of Mumbai...
What about that Krish Raj?…
igner called Christophe Barreau.
http://www.christophe-barreau.fr/
We design sail catamarans from 40' to 80' and occasionally some other stuff.
One may know it's a quite uncertain activity so I find myself tacking upwind on other seas from time to time, such as product design and jewelry. I also have side projects with mates regarding hi-fi or RC planes.
As for "static" architecture I had a couple experiences working on large "complex" buildings. Sadly French architects are not very familiar with BIM, parametric or even precise 3d modeling so I've been hired to introduce GH in the workflow.
I'm an un-authorized rhino trainer, sorry to say, but I just love teaching and meeting new faces, although I'm not as devoted as Danny ;)
I've been using GH both for modeling and analysis for about three years now and I'll daresay I became pretty good at it... I'm not a geek at all but it's just so useful, and it's really worth it sometimes €€€!…
ke 20 samples per day, 50 days out of the year for 1000 samples) from each panel and calculate the % of occlusion. Allow that % to be the % "open" of each panel. Design the opening in each panel to be something cool and proportional. Profit.
You could even break it down by a finite number of available panel types(say 0%, 20%, 40%, 60%, 80% open) and create an efficient production. All of these things can be paramterized to allow for more samples or more panel types as needed or based on your calculation limits.
The only exception would be proper environmental analysis, say, if you were trying to reduce solar gain in summer and allow for it in winter. You would want to split this calculation between when you need to be gaining heat and where you want to be shading. Then extrapolate the percentage between the two. You may even need a gradient of heat gain through fall/spring. The possibilities depend on how much you know about the mechanical requirements of the area/building.
That would be my approach. If I have more time tonight I will try and put something together on this as its been something I'd like to have in my back pocket....
Edit: You would also need to analyze the angle of incidence as it could have an effect on the amount of solar gain.....…
pproach of estimating wind loads using design codes such as ASCE7-05.
B) Hiring a wind expert to construct a physical model and and calculate wind pressures measured directly from a wind tunnel test.
A) will allow you to derive a site specific wind design pressure based on the height of the building, surface roughness, site location etc. Typically you then multiply this pressure by an appropriate co-efficent in the code for a given building shape.
The other atypical method it to use numerical approaches such as CFD. This approach is not yet accepted due to nuances such as of surface roughness.
Building deflection is again subjective. Doing a modal analysis and getting an idea of the frequency is better. You can increase the frequency by playing about with the building stiffness.
You need to modify the stiffness of the building to get the deflection down. i.e. play about with geometry, add extra members with stiffness, reduce weight, use material with higher elastic modulus etc
If you are getting a 7m deflection for a 400m building then I can right away that is way too soft. That is equivalent to 400m/7m or H/57. You want to be at least H/500 to H/1000 so aim for 80 to 40 mm.
Your wind load seems reasonable at 87 psf for that height of building
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