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BIM mudeliga loodud moodulmaja 3D teostusmõõdistus maapealse laserskaneerimise tehnoloogiaga

Mesila, Karlis (2016) BIM mudeliga loodud moodulmaja 3D teostusmõõdistus maapealse laserskaneerimise tehnoloogiaga. [thesis] [en] As built measurement of a console house created with BIM modeling.

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Abstract

Maapealne laserskaneerimine on tänapäeval muutunud geodeesia valdkonnas üheks lahutamatuks osaks. Erinevate tellijate soovid on muutunud järjest spetsiifilisemaks ja detailsemaks, mistõttu on mitmed tavapärased geodeetilised instrumendid hakanud ajale jalgu jääma. Samas, erand ei kinnita reeglit. Laserskaneerimine on muutunud populaarseks just keeruliste ja väga mahukate objektide puhul. Skaneerimistäpsuse hindamiseks sobitati tasapinda üks väike osa punktipilvest. 23 341 143 punktist kasutati selleks 589 466 punkti. Kogu kombineeritud standardhälve (∆c) viga on ligikaudu 2 mm. Kõik teljelised hälbed (∆x, ∆y ja ∆z) jäid alla ühe millimeetri, millest võib järeldada, et punktipilv on antud töö sooritamiseks väga hea. Võrreldes kahe mudeli omavahelisi tulemusi, saab järeldada, et teoreetilise BIM mudeli põhjal loodud moodulmaja ja punktipilvest modelleeritud 3D mudeli omavaheliste hälvete erinevus on minimaalne. Teoreetiline mudel võrreldes mõõdistusmudeliga on hoone elementide kaupa erinev. Keskmine erinevus oli 0 millimeetrit, mis on väga hea tulemus, arvestades seda, et vigade tekkimise võimalus on väga suur. Peamiseks puuduseks antud töö puhul võib välja tuua punktide tiheduse, mistõttu moodulmaja detailsemad elemendid jäid modelleerimata. Kasutades laserskaneerimise tehnoloogiat oleme hetkel olukorras, kus taolise objekti skaneerimise ja joonestamise aja vahekord on liialt aeganõudev. BIM mudelit on küll visuaalselt hea 3D-s vaadata, aga taolise objekti puhul oleks olnud efektiivsem kasutada nt elektrontahhümeetriat. Või ka kiirema tööpõhimõttega laserskannerit. Kuna mõõdistamise aeg oli piiratud, siis kiirema tööpõhimõttega laserskanneri puhul oleks antud mõõdistusaja jooksul saadav punktide tihedus suurem, mis oleks eeldatavasti esile toonud ka väiksemaid hoone detaile. Laserskaneerimine tuleb kasuks siis, kui tegemist on keeruliste ja detailide rohkete objektidega. Sellise meetodi kasutamine on kasulik nii tellijale kui ka ettevõttele endale. Ettevõte saab vähendada sellega oma kulusid, sest ressursi kulu taolise metoodika puhul on väiksem ning tellija saab oma projekti varakult kätte, kuna laserskaneerimise andmetest modelleerimine ei ole niivõrd aeganõudev. Antud lõputöö tulemustest võib järeldada, et maapealse laserskaneerimise tehnoloogiaga saadav tulemus võib olla väga hea usaldusväärsusega, et seda kasutada teostusmõõdistamisel.

Abstract [en]

Terrestial laser scanning has become an inseparable part of geodetics. The wishes of different customers have become increasingly more specific and detailed, wherefore many ordinary geodetic instruments have started to become obsolete. However, there are exceptions to the rule. Laser scanning has become popular in the case of complicated and very extensive objects. In order to evaluate the scanning precision, one small part of the point cloud was placed on a plane surface. For that, 589,466 points out of 23,341,143 were used. The total combined standard deviation (∆c) error is approximately 2 mm. All axial deviations (∆x, ∆y and ∆z) were less than one millimetre – it can be concluded that the point cloud is very good for performing such a task. Comparing the results of the two models enables to conclude that a difference in the deviations of the modular building created on the basis of a theoretical BIM model and the 3D model modelled from a point cloud are minimal. The theoretical model differs from the survey model by building elements. The average difference was 0 millimetres, which is a very good result, considering that the chances of errors are very great. The main deficiency that can be pointed out in the case of this work is point density, which is why the more detailed elements of the module building were not modelled. Using terrestrial laser scanning technology, we are currently in a situation where scanning and drawing this kind of an object is too time-consuming. A BIM model is visually good to look at in 3D, but with this kind of an object, it would have been more efficient to use e.g. electron tachometry or a faster working laser scanner. As the time for taking the measurements was limited, a faster working laser scanner would have provided a higher point density within this measuring time, which would have presumably specified the smaller details of the building. Laser scanning is beneficial in the case of complex objects rich in details. Using this method is beneficial for both the customer and the company itself. The company can reduce its expenses because fewer resources are used for this method and the customer can get their project early, since modelling from laser scanning data is not that time-consuming. The results of this final paper enable to conclude that a result gained from terrestrial laser scanning may be very reliable to use for taking as-built measurements.

Item Type: thesis
Advisor: Tarvo Mill
Subjects: Construction > Applied Geodesy
Divisions: Institute of Construction > Applied Geodesy
Depositing User: Karlis Mesila
Date Deposited: 27 Jun 2016 07:18
Last Modified: 27 Jun 2016 07:18
URI: http://eprints.tktk.ee/id/eprint/2286

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