T3 Season 2, The Model


Its T3 time again but first I have started tagging people that have entered T3 in the past on their member icons its a very small recognition for their valuable contributions which have driven APM forward faster than it might have without the competition. They have not only put their equipment on the line discovering new ways of doing things but countless hours as well.

Unsung heroes in the development of low cost autopilots for all.

So lets get into this round.

I waste far too much time on the most excellent GEFS there could be more 3D buildings laid on top of the Google Earth base layer. Lets change that.

The last T3 challenge "The Cube" bought some really outstanding results and the natural progression from this is automated flight around a building or natural point of interest and the creation of a 3D model perhaps in 123D catch of the subject. Last November Alan Sanchez showed us how. Improvements in the multirotor code that came into play at the Sparkfun AVC will help with the flying.

This could be achieved with a fixed wing platform with a little thought.

We should have some ground rules (pun intended) you must seek permission to make a model of the building, or natural wonder! You should fly no higher than 130m and the flight should be hands off all the way and you should stay visual with the airframe at all times. Please do not create a model of something in class A airspace unless it's at a recognized model aircraft field.

The flight must be at very least autonomous from just after take off to just before landing. If you can do it all autonomously bonus points! FPV entries will not be permitted.

If you submit your model to Google Earth and get it placed bonus points when it appears on GEFS for me to fly around it. In this case the model might be skinned with images taken from the air.

This is no simple task so it should remain open for six months. Normally I tack time on at the end so to break with tradition lets start the competition on the 1st of August and run all the way to 1st Feb 2014! That gives folks the extension weeks in advance!

Prizes to be announced when I have finished twisting CA's arm. As we know he always comes good.
I am also putting out a call for volunteer judges from the ranks of previous T3 entrants to help me decide. This one is I think going to be very subjective and how attempts are documented is going to be a big factor. 

There is no doubt automated building inspection will be a part of the future for sUAS.

Good Luck, be safe


Now let the traditional but did you mean XYZ questions begin! Oh and if you are tooling around on GEFS as well look out for me as Gary sUAS News, often slope soaring ;-)

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  • T3

    Our team entry to the contest:  

    The Mytilene fortress, Lesvos Island, Greece


    The Mytilene fortress stands on a small hill, the highest point on the peninsula, between the city’s northern and southern ports. It was the largest and strongest of its kind in the Eastern Mediterranean. In ancient and Byzantine times, this peninsula was an island, separated from the rest of Lesvos by the Strait of Euripos. The Euripos was located approximately where Ermou Street is today and connected the northern and southern harbors. Silt and human intervention eventually eliminated the strait, transforming the islet into a peninsula.
    The original nucleus of the fortress, designed in Byzantine times, is believed to have been built on top of the ancient acropolis. The first significant alterations to the fortress were made by Francisco Gateluzzo in 1373 during the period when the Gateluzzi family occupied and rebuilt the island (1355-1462). Other changes and additions followed, the most important of which was made in 1677 by the Ottomans, who were responsible for the lower north section of the fortifications. For construction material, they used many blocks from older buildings, particularly the ancient theatre of Mytilene, which was by then in decline. After the liberation from the Turks in 1912, the fortress was used as a barracks. The wanton use of the fortress after 1912 as a source of building material to construct refugee housing gradually brought about its ruin.
    Today you can distinguish the following sections of the fortress:
    •     The Acropolis (Upper Castle), on the southern and highest section of the hill.
    •    The Main Precinct (Middle Castle), the largest section, built by the Genovese Gateluzzi family.
    •    The Lower Precinct (Lower Castle), in the northwestern section, whose construction dates from the Turkish occupation.

    Our goal was to use the UAS and GIS technology to offer a modern map as reference to the ephorate of Prehistoric and Classical Antiquities plus an easy to follow high detail map for tourists.


    This is the Produced 3D model

     (click to view in 3D)


    An Orthophoto resized


    A Single Pic:


    The DEM:


    The TLOG Flight Path


    Some Specs:

    Airframe: Phoreas

    Autopilot: APM 2.5, Ublox

    Camera: Canon ixus 100is APM control via CHDK

    Flight Height 115m AGL 

    Ground Resolution 3.5cm/pix

    GeoTagged with Mission Planner

    Non Stabilized gimbal

    Number of Pics: 101

    Number of Control points: 15

    Software: AgiSoft Photoscan, ArcGIS 9.3, Autodesk AutoCAD 2010, 123 Catch.

  • T3

    José, magic formula sounds interesting! :-) What is it doing? I'll post details early next week.

    Jarret, do you have any experience with the Photoscan feature to classify points as ground?

  • T3

    Stephen, maybe you can try to decimate your mesh to 500 000 and export model as .obj to share with sketchfab or other Webgl online viewer.

    Result could be nice

  • T3

    Take care with .las from photoscan, with the spars cloud export there is not problems, but with dense cloud export the file from my blockaus is up to 6Go in low reconstruction for a poor quality.

    Geotiff DEM and orthophoto will be easier to export

    Will have a big look at, seem very interesting

  • T3

    Interesting read Jarret.  My lab actually uses point clouds for ecological work.  You can read more at  I'm the resident copter guy, and I'm making this textured model specifically for T3.  If you're interested in chatting with us about the data processing side of things, I'd be glad to put you in contact with our PhD student Jonathan.

  • Hi Stephen,*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_*1_nav*4responsive*4tab*4profile_*1#!

    Here is a link to an article comparing the pros and cons of a point cloud and a 3D reconstructed textured model it is interesting. Photoscan also has a new feature to classify points as ground or not ground to create a true digital terrain/elevation model it might be interesting to see what it does to your data. I have also had limited success in using the lidar point cloud processing LAStools on photogrammetrically derived point clouds. I don't have a UAV or Drone of my own at this moment so my main reason for visiting this site is to see what people are doing with their data which is very interesting to me.


  • T3

    Thanks for the tip Jarret.  I'll include .las files in my final entry.  And my workflow will be documented.

    Looking forward to reading your entry Thorsten!  You could do some serious ghost hunting with that IR camera :P

  • Hello, Thorsten: I loved your example. Let me tell you that a friend of mine has got a kind of magic formulae so he is able to "read in the darkness" on dsm. I'm rather sure he would give bird to a new story out of your work in archaeological terms. I kindly ask you to post me for further details if you would like him to have a look on that tomb. this is serious!.

  • T3

    Hi Stephen, I'll post some update within the next few days here as well a over at I just updated my workflow so I have to re-run everything to make it nice. Since, it is both RGB and IR it takes a while.


    The link to download QT Reader is on this page, there is also their not free QT Modeler which is very handy for working with point clouds.


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