on 2: I think the reason to draw a fitness landscape is to highlight graphically the presence of local minima, even in a simple optimisation problem. In architectural terms, this means getting an idea of how many sub-optimal solutions there are in a problem, which helps while exploring conceptual design proposals.
Have a look at this very basic example (which I published with two colleagues on "Shell Structures for Architecture", chapter 18): a shell footbridge (24m x 4m footprint), which is generated by two parabolic section curves (the two apex heights are the two design variables). The maximum displacement of the structure under gravity load and self-weight is the objective function. Simple example, but several local minima and interesting shell forms (image below).
@AB,
The expression used by David in the Number of Samples Input is a simple “x+1”. By grafting the Divide Curve Output, he got 81*81 lenghts (6,561 values). You have to make sure that number is divisible by the no. of samples. The second expression used for the Length output is only a scaling factor (my guess), to control the height of the fitness landscape drawing.
Cheers…
n account of the position of the sun and weather cannot be expressed in terms of a single set of luminous intensity values (which is what IES files do).
With regards to your example files, I agree with Chris. The primary reason for the low illuminance levels is that the light bounces are getting lost in the tube. Have you checked with the manufacturer/distributor if the location of the IES file should be inside the tube and not flush with the ceiling? Physically modelling such tubes in lighting software like Radiance (which is what HB uses) or AGI32 is a fairly expensive proposition. This is one of the reasons why manufacturers provide photometric data for such devices (however simplistic that data might be).
The candelamultiplier increases or decreases the luminous intensity values. So it will have a direct impact on the calculation. The primary reason for having that input was to enable users to do some testing with different lamp types and environmental factors such as dirt depreciation. You need not change them for your simulation. Assuming that the IES file is inside the tube, in order to make this calculation work inside HB you'd have to crank up the calculation settings to a very high level (start with -ab 10 -ad 4096).
Finally, due to shortcomings in the annual simulation software (Daysim), IES files will not work directly work with annual calculations. However, there is a fairly easy workaround for that issue. In case you are planning to run annual calculations with IES files, please let us know here.
Sarith…
ing illuminance and limiting exposure (lux hours). Hours with direct solar irradiance are likely to exceed the limiting illuminance thresholds, which range from (200 to 50 lux as per Table 3.4 in CIE 157:2004). It makes sense to consider direct illuminance (an ab=0 simulation in Honeybee) separately from a normal illuminance calculation.
Assuming that the museum exhibits have low to high responsivity to light, an ideal solution would minimize direct sunlight. For daylight from the sky and reflected light, it might be enough to keep the illuminance levels below the recommended thresholds and then sum up lux-hours.
Daysim, the annual daylighting engine used by Honeybee and DIVA, is not very accurate for direct-sun calculations. You will get more accurate results if you run your analysis with Radiance directly.
Instead of considering the horizontal illuminance grids, one can create grids that correspond to the dimensions of the exhibit and then average those values. I think single points, as shown in your gh file might not suffice. Calculating lux-hours is by far the simplest part of such a simulation. It will only require averaging these points, extracting them into an array and then summing up that array.…
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…
ysim.ning.com/
When you run the simualtion you will notice on the batch terminal that Daysim is also being called, so you may want to consider how Daysim uses Radiance files & data.
Regarding your current problem, I think you stumbled onto something weird and interesting.
Interior and exterior readings appear to differ by 40 in the best case scenarios. Even setting the transmittance to 1 yields similar results. I tried changing from cummulative sky to climate sky and got similar values. Changing the test points did nothing either.
I think, (yet I'm too lazy to prove this) that the difference in values stems from diffuse radiation over the sky dome.
If you delete everything except the glass you'll notice that interior values are like 80-90% of the exterior values (this seems like the expected behaviour with a transmittance of 1). So, if we consider that a vertical window, part of an opaque box, is receiving radiation from 25% of a sphere, as you start to inset the interior test points the radiation they receive will be a fraction of the 25%.
Let me try to explain this better...The exterior surface receives radiation from a section of a sphere calculated by 180degrees on the xy plane (let’s call this angle theta) and by 90degrees (let’s call this angle phi) in azimuthal elevation. If you integrate this over spherical coordinates (theta from 0 to pi; phi from 0 to pi/2) you will find that it comes to a quarter of a sphere. By comparison, the interior surface will not integrate theta from 0 to 180degrees,nor phi from 0 to 90degrees, instead it will be the subtended angle from the exterior surface as a function of their separation; the farther in you go the smaller the view of the outside.
If my hypothesis is correct there shouldn't be that much difference since the separation is only 10cms...the subtended angle would be like 170 instead of 180 for theta and 85 instead of 90 for phi...overall if you integrate both spherical areas there should only by a difference of 10%.
In conclusion, I believe the unexpected behaviour stems from the previous subtended angle thing. If direct radiation was the only factor the difference would be the aforementioned 10%, which suggests that an additional source of energy is also affected by this. Perhaps indirect and diffuse radiation from other areas of the sky dome.
I’m definitely intrigued on why this is happening. Please post if you figure it out.
Regards,
Mauricio
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rld.wolfram.com/EnnepersMinimalSurface.html
when i type the equations for z,y,z it says a syntax error so i obviously do not understand how to construct an expression. (screen capture attached)
Any help/explanation of using this function would be greatly appreciated
thanks so much
Capture.JPG…
hen you determine their position and number by the "precision_" input. Their number is equal to "precision_ - 1".They are essentially mesh edges, not curves. To hide them, in Rhino application menu choose: Tools -> Options -> View -> Display Modes -> choose your current display mode, and uncheck the "Show mesh wires":
b) How do you change the x- and y-scale of the chart? For instance displaying every 10 degrees of azimuth?
Can you be a bit more precise?You would like to change the labeling of the azimuth directions from 30 degrees step to 10 degrees step? If this is so, you can not do that.
c) My input surface is a hyperbolic paraboloid, facing south symmetrically. How does the component calculate its tilt and azimuth?
All Ladybug Photovoltaics components calculate the amount of AC energy generated by a planar (flat) surface. Tilt and azimuth angles are calculated based on surface normal at 0.5, 0.5 surface parameters. So you can not use the hyperbolic paraboloid as the _PVsurface (or _PV_SWHsurface) input, as it will yield incorrect results. You need to planarize that hyperbolic paraboloid surface first.I attached below an example with default grasshopper components, but the size of the panels is not equal. If you want them to be equal use some paneling Grasshopper plugin like Lunchbox or Paneling tools.…
2d grid from
grasshopper but in 3d, fully controllable of course. I want to do something
like the image in this web
site:http://news.cnet.com/Photos-Weaving-high-tech-fabrics-of-the-future—page-12/2009-1008_3-5667576-12.html
I figured that connecting points and lines kind of works (point and line input AB command) but the line length changes when I move a
point. What I want to be able to do is to move a point and drag others but keep
the line segments constant, just as a real net.
…
Added by Jesus Garza at 8:28am on February 23, 2010
ehow acquire different settings/are calculated differently. Appears at random “rows” of points, sometimes it all works fine, so I need to do a series for the error to show. See images below.
In the Ladybug fly run the VT of the window changes.
It’s taken me a day and a half to track this error down. Phew.
I get the same error on two different comps.
What is causing this? Does anyone get the same error? Images below created with RADquality set to 2, and 7 cores. Fiddling with Radsettings dont help, I think, except error goes away with very low ab.
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y case. Here's the thing. There is this subject at my university where we are assigned a famous building and we need to recreate it in Rhino. We're given bonus points if we manage to code some interesting part of it in Grasshopper. So far so good, I'm doing pretty well with Rhino and by far I am happy with the results I've achieved with modelling the given building. Harbin Opera House by MAD is the building I'm trying to model. There is one particular surface:I've built this surface in Rhino and now I'm trying to map pyramids on it. Not only have the pyramids to be different in height, but their height has to be dependent on the curvature of the surface. I'm getting some results but it seems to be exactly the opposite of what I need. I want to have higher/spikier pyramids where my curvature analysis shows red/blue and lower/slopier pyramids where the analysis shows green colour.At the moment I'm not really sure how the code I have works, but it seems that the height of the pyramids is dependent on a distance from a point in space to the projection of the cap-point of a pyramid.Here're my Rhino and Grasshopper files:surface1.3dm
surface1.ghI'd be grateful if someone of you guys could handle my problem. I've got one more issue with this surface, but once I get a solution to the first 1 will let know what the second one is.Thanks in advance and keep well!…