The Forces of G

    Overall, I found the articles "Roller Coaster Construction" by Alejandro Zaera-Polo and the "Prelude" to be easier to read than the last couple of assignments but no less interesting.  With that said, I focus this blog with the one paragraph out of both of the articles that I had to re-read several times before I even started to think that I understood it.  This paragraph is the final paragraph of the "Roller Coaster Construction" article, which is in fact the exact paragraph that gave this article its name.  

    I couldn't see the relationship that was so bluntly described by one of the contractors between how this building couldn't yet be laid out and how roller coasters where built.  So, thinking that I just didn't know enough about roller coasters I did a little research about them.  Through Google I found a lot of good websites but the best one is from madehow.com (http://www.madehow.com/Volume-6/Roller-Coaster.html).  This website goes into pretty good detail about roller coasters in general, but also describes the design and construction process.  

    Just as I had originally imagined, roller coasters are designed in full detail before construction even begins.  This makes sense not only due to the intricate geometry, but also do to the importance of safety for a structure like this.  The public is going to use this structure with full confidence that it is safe, after all who goes to an amusement park with anything in mind other than having careless fun.  Not to mention that "g forces" play a huge roll in the popularity and usability of roller coasters, which means that a large amount of effort on the design side of the process must be used to determine and evaluate the resulting g forces throughout the ride of the proposed roller coaster.  It seems that a roller coaster is designed fully, down to every nut, bolt, and point location, before construction even begins.  So the last paragraph couldn't possibly be saying that the proposed building is similar to roller coasters because the design of either is not complete (and therefore cannot be laid out) prior to the beginning of construction, since this is clearly not the case with roller coasters.

   My next thought was that maybe the last paragraph was saying that the geometry of a proposed roller coaster could change based on the manufacturing and construction systems available, and the same was true for this building.  If this is the case then all structures and objects can be thought of as similar to this building.  If something can't be physically built due to manufacturing or construction limitations, then a change must be made so it can be built.  I decided I don't think the last paragraph was trying to make such an obvious link between the two structures.  Furthermore, in the case of a roller coaster, the entire thing would need to be re-designed to insure the safety and usability of the structure, based on the necessary construct-ability change.  This doesn't completely seem like the case for the proposed building, at least from what I took from the article.  Instead, it seemed like the article and the last paragraph was saying that small changes in the geometry and the form of the building could be made relatively easily (and quite frankly expected) during the construction process once realizations were made about what manufacturing and construction systems were being utilized.  I decided that this could not be the conclusion the last paragraph was trying to draw.

   Maybe the similarity between the construction of the building and the construction of a roller coaster is that a proposed roller coaster usually has original, unique aspects of its design that has never been built in a roller coaster before.  This leads to testing and partial construction of pieces of the final roller coaster in a lab to insure that the new features will perform as designed.  The same is partially true for this building, at least the fact that the geometry and form of this building has never been built before.  This could lead to testing in the field to make sure the designed connections can actually be made and that the materials can in fact withstand the loads.

   Instead, the final paragraph could be referring to the fact that both the roller coaster and the building must be built using local geometry.  A roller coaster must be built in a certain sequence, and a contractor can't really lay out a part of a track until the supports and the track before it is built.  While it could be technically tied back to a given point on the site, this would do no go because it won't be able to put into place until it's turn in the sequence due to how the tracks slide together and are supported.  Therefore it is much easier to use local geometry to define the location of the piece since it is easy to see where it goes relative to the last piece if it is already constructed.  A roller coaster is constructed similar to reading a treasure map.  A treasure hunter cannot take the 10 steps forward after a left turn if he hasn't already taken the 20 steps to get to the left turn.  The treasure hunter cannot locate the X when he starts to read the map because the X is locally defined based on the steps right before it, resulting in the treasure hunter having to follow the map in order.  This also sounds like the case for the proposed building.  A given roof panel (or any aspect of the building) may be defined based upon its surrounding geometries instead of back to one main point on the site, making it difficult for the contractors to lay out that piece until its appropriate time comes.

   After further thought, I came to the conclusion that this is in fact what I thought the contractor meant when he compared the building to a roller coaster in the last paragraph.  It was not about the design not being complete before construction, the ease of changing the design based on the construction systems, nor the fact that this form had not been built before in the past, but instead the last paragraph was drawing similarities between the local definition of the pieces and geometries of the structures.  This seemed correct to me, at least until I recalled that the previous page stated that the design had to move "from a raster space, where each point is determined by local information, to a vectorial space, where each point is determined by differentiated global orders".  Alas, it seems that the points of the building were not defined through local geometries, and once again confusion set in.  So, knowing that each one of you must comment on my blog and while you can comment about whatever you would like, I would encourage you to comment about what you thought the last paragraph meant (or what you think it meant based on my analysis if you didn't read that article), since I would be sure to find your interpretation of the last paragraph very interesting.