You can download the raw 3D models in OBJ format. Besides, you can convert the OBJ files into other formats by using the Offline Format Converter in Altizure Desktop. Please find the tutorial for Format Converter here.
The formats that you can convert the OBJ files into include PLY, OSGB, KML, DAE, STL, orthomap, etc. You can download the free sample assets of obj files, orthomap, elevation map (DSM) and Google Earth 3D model at the bottom of this page.
No. However, you can convert a free project into a pro project and download the assets.
Our 3D reconstruction engine is tuned to generate high quality 3D models from images. However, high quality also means huge data size and this put great pressure on lower end computers and devices when they need to handle one, for example, in transferring over internet, in editing the 3D models or in rendering and etc. To tackle the problem, we have employed a technique called level-of-detail (LOD) to systematically simplify and break down large 3D models into smaller pieces which we call tiles and organize them in a quadtree structure. This technique allows our engine to handle large scale 3D models more conveniently and offers you a greater flexibility in handling the models as you can choose a comfortable level-of-details model to work with according to your constraints and needs.
In conclusion, each OBJ file in model.zip represents a particular tile of your model at certain level-of-detail. You can get the complete model after you have loaded all the tiles at the same level together into your software.
Every OBJ file is named with 3 numbers. Take the file “tile_1_0_16.obj” as an example. The first number (i.e. 1) represents the level-of-detail (LOD). The smaller the number, the more simplified is the model. The second and third number (i.e. 0, 16) represent its x-y location in the model respectively.
Since the tiles are organized in quadtree structure, every step up in LOD will bring 4 times more number of tiles. Tile area will also shrink by 4 times and its length will shrink by half accordingly. Therefore, the step interval in second and third number will shrink by half as well. This process repeats until it reaches the highest LOD. By then each tile cannot be further broken down and we define its length as 1 unit.
Take our sample data, HKUST_CYT_Building, as an example. This dataset has highest LOD at level 5. Therefore, it has 2^5 = 32 tiles in both x and y direction at LOD5 and as such we says the model has a size of 32 times 32 unit large.
In LOD level 5, the most detail level is reached and each tile has a length of 1 unit. Therefore:
tile_5_1_0.obj is right next to
tile_5_0_0.obj. The x coordinate is jumped by 1 unit.
tile_5_0_1.obj is right above
tile_5_0_0.obj. The y coordinate is jumped by 1 unit.
In LOD level 4, each tile has a length of 2 unit. Therefore:
tile_4_2_0.obj is right next to
tile_4_0_0.obj. The x coordinate is jumped by 2 unit.
tile_4_0_2.obj is right above
tile_5_0_0.obj. The y coordinate is jumped by 2 unit.
In LOD level 3, each tile has a length of 4 unit. Therefore:
tile_3_4_0.obj is right next to
tile_3_0_0.obj. The x coordinate is jumped by 4 unit.
tile_3_0_4.obj is right above
tile_3_0_0.obj. The y coordinate is jumped by 4 unit.
In LOD level 2, each tile has a length of 8 unit. Therefore:
tile_2_8_0.obj is right next to
tile_2_0_0.obj. The x coordinate is jumped by 8 unit.
tile_2_0_8.obj is right above
tile_2_0_0.obj. The y coordinate is jumped by 8 unit.
In LOD level 1, each tile has a length of 16 unit. Therefore:
tile_1_16_0.obj is right next to
tile_1_0_0.obj. The x coordinate is jumped by 16 unit.
tile_1_0_16.obj is right above
tile_1_0_0.obj. The y coordinate is jumped by 16 unit.
In LOD level 0, each tile has a length of 32 unit and is as large as the model.
Therefore it has only one
You must first understand the quadtree structure and the OBJ file naming principle among model.zip before understanding the file generated by using the Merge function. If you set the block size as 32 (which is the default block size), the Format Converter will merely merge the OBJ files in model.zip for every 32 by 32 unit area, and then generate the merged OBJ files. You can roughly view them as a larger piece of tile. They still maintain LOD but no longer quadtree structure. The purpose of it is to offer users a more handy control over their models as they do not have to import a large number of fragmented pieces into software everytime.
Here is an incomplete list of both free and professional softwares that read OBJ file:
You can use this feature if you meet the following conditions:
A step-by-step guide:
Importand select the downloaded tif files. Then the viewpoint will fly to the geographical location of your model. Choose
scaleto upload your orthomap on Google Earth Pro.
You can use this feature if you meet the following conditions:
Please obtain the
KML files by using our Offline Converter in Altizure Desktop. To display your 3D model, you can directly upload these files to Google Earth.
DAE files contain the geometry information of your models. By importing them, Google Earth will place your models in the current viewing location.
KML files contain additional GPS information so by importing them, Google Earth will place your models according to its GPS location.
To import them:
Openand select the downloaded
KMLfiles. In the following example, we imported the
You may notice that the models sometimes sink below the Google Earth terrain surface. This is due to the lack of altitude information in GPS. You can fix it by manually adjusting the altitude.
To adjust altitude:
At the moment, we only provide kml and dae output up to level 5 because Google Earth cannot load higher resolution models in one batch.
KMZ is in fact a zipped format. Therefore Google Earth will have to unzip it on the fly tiles are loaded. We suggest unzipping the KMZ file like a normal .zip file before importing into Google Earth. After unzipping you can import the Project_LOD.kml file.
We are constantly improving our engine and providing more and more downloadable assets. If your project is reconstructed in an early time, the download assets in your project may not be up-to-date. In this case, please contact us by clicking the
report problem button on the overview pages. We will arrange a free update to you after confirming the problem.
Below are the sample downloadable assets from Cheng Yu Tung Building and some other file formats that can be generated by Converter. Please feel free to download and test these samples. If you have any question, please contact us in the forum or firstname.lastname@example.org.
The following formats can be obtained by using Altizure Offline Format Converter: