17000 points in space 

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Joined: 7/27/2012
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I am currently working on a project where i need to install i.e. 17000 fixtures for a spatial roof structure. I need to mount the fixtures in unique posisition due to the shape of the roof surface. 
The surveyor on the project has a Leica 1203 totalstation, and my request is ideas to handle the large amounts of points to be able to methodically place the fixtures. The points are extracted from a Rhino3D model, and can be given as a spreadsheet - the surface will most likely be handled in sections of 100 fixtures. 
Any ideas will be appreciated!
Jacob Drachmann
Civil Engineer
Pihl & Søn A/S - Denmark
  Friday, July 27, 2012 at 4:52:25 AM
Posts: 9

Joined: 11/6/2008
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Response from our Editorial Board member:

Without knowing more details of the project, it appears that this layout should be fairly easy to execute in the stakeout mode of standard surveying software and total stations. The laser "pointer" mode can be set and if it is dark enough then the layout points will be visible. You noted that the unique position of the fixtures due to the roof shape; you may want to to add 3 or more alignment marks on each fixture in the model (if 3D alignment is required). Also include in the model many reference marks for the total station to backsight on.

Renting construction layout lasers could be cost effective for a one-off layout of this kind, but the total station should be fine (depneding on light conditions).

Exporting 3D linework will help the total station operator visualize the layout in the surveying (data controller) software. Most software can intake DXF, and your spreadsheet can be imported as a delimited point file. Another interesting layout tool is the 3D-Disto - a kind of mini-total-station desgined for BIM and building construction layout work.
  Thursday, August 02, 2012 at 4:02:35 PM
Posts: 9

Joined: 11/6/2008
Reply  Re: 17000 points in space Flag »  Reply »
Response from our Surveying Editor:

This reply is necessarily based on some degree of assumption since there isn't really enough info to give a step-by-step definitive answer.

Mr. Drachmann mentions 17000 fixtures FOR a roof structure, but further comments indicate that he means "on" a roof structure. 

We could further infer that he likely means "on the ceiling", but says on the roof - two (2) entirely different things which I will deal with momentarily.

The mention of extracting points from a Rhino3D model indicates the presence of a 2D datum in North and  East plane coordinates, with elevations as the third dimension.  Since he speaks of staking out for fixtures using a Leica instrument we must also assume that the 3D coordinate system for the structure also exists on the ground. 

First - Read the manual for either the data collector or controller that the surveyor intends to use to operate the instrument, or, the manual for the instrument if the surveyor intends to use the onboard programs.  In this way determine what formatting conventions the program uses for point files, and how they must be delimited - by commas, by spaces, etc. Then, number the points extracted from the 3D model, save the delimited file, and transfer it to the stakeout software.  Break it into manageable sized (100) point groups if necessary.   

Second - The Leica 1200 series can be optionally fitted with PinPoint - a reflectorless EDM (RL mode.)  If this one has PinPoint the Laser will make a small dot on the structure at the appropriate place when marking a point regardless of being on the roof or on the ceiling. 

Third - If the Leica 1203 does not have PinPoint then the fixtures must be staked out using a prism on a pole or a point.  This means that accounting must be made for a prism height. In the stakeout software the prism height will be automatically subtracted.  This is ideal if the fixtures are on the roof of the structure since a subtracted rod height will give you the correct elevation on the roof surface. HOWEVER, if you are staking on the ceiling of the structure then you must enter the rod height as a negative number which will algebraically correct the elevation, since a rod height held under something would need to be added to produce the correct elevation.

  Tuesday, August 07, 2012 at 10:32:05 AM

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