A. Data Format Requirement

OBJ Data Format (required)

B. Parameter Setting & Operation Steps

  1. Upon completion of Aerotriangulation, Reconstruction menu will be generated, you could select "No tiling" (small project)or "Regular Planar Grid"(large project)as Tiling Mode in the Spatial framework tab. Currently, ”Regular volumetric grid” or ”Adaptive tiling” is not well supported.
    批注-2019-09-05-204047.png

Note: the coordinate parameter here in the "Spatial reference system" must be the same as that is selected in B.3.

  1. Clicking Submit new production, "OBJ wavefront format" should be selected as Format in the Format/Options tab, tick "include texture maps", leave "Level of detail" unchecked. Select "Tile Overlap" and keep its default value (which will be auto-computed from the system, it is not suggested to set into 0.049 meter as pictured). Other options setting can be adjusted according to the user needs.
    WeChat Image_20191009144254.png

  2. Click Next and come to Spatial reference system tab. Note: the coordinate parameter here in the Spatial reference system must be the same as that is selected in B.1. Otherwise, the final model will not display in normal mode.(In addition, "China Geodetic Coordinate System 2000 - China 2000 (EPGS:4490)" should not be selected. You must choose the relative coordinate system with the origin.)
    捕获.png

  3. If the aerotriangulation files and photos after distortion correction need to be imported, please follow the steps as below: click a Block_AT on the left panel, select Block->Export->Exprt to XML in the menu bar, choose "BlocksExchange XML format" as Output format and "Rotation matrix" as Rotation format, finally check Export photos without lens distortion.
    图片4.png

Note: the coordinate system outlined in the red box needs to be the same as those selected in B.1 and B.3 in order to keep the same coordinate systems between the camera and obj.

  1. Finally, double check the export result:
  • The result should be packages of Tile_+X_+Y folders,each folder represents a Tile, including a obj model, mtl material file and relevant texture file.
  • Please use Meshlab to open the obj model so that it can display normally.
    图片5.png
  • Select Render->Show Box Corners from the Meshlab menu. Make sure each Tile is a rectangle (rectangle or square), the model edges are aligned to the XY axis, and the Z axis corresponds to the elevation. Meanwhile, you can use the buttons in the menu icon to measure the coordinates of model's four corner points. The X or Y value of the corner point should correspond to the Min or Max value in the Bounding Box.
    图片6.png

C.Upload to altizure.com

Compress the obj model and metadata file into .zip package and upload to altizure.com.

  1. Zip file#1 & #2 into file#3 and upload it to altizure.com
    图片7.png

  2. Click Create, select Third-party Model and click Photogrammetric Model.
    图片8A.png
    图片9A.png
    图片10A.png
    图片11.png

  3. Upon completion of the conversion, your context capture results can be viewed on the Internet without any restrictions. Besides, you could put the model on the [Planets] (https://planets.altizure.com) for more creation and application.

D. FAQ

  1. Q: What to do when the zip archive is too large to upload, or the conversion process prompts "zip file error"?
    A: You can use the 7zip or other tools to perform volume compression. Divide a large compression package into files of about 200 Mbyte each and then upload all these files to the project.

  2. Q: When the context capture model is uploaded for conversion, many cracks appear as the following figure. How to solve it?
    cc_screencap.jpg
    A: This problem is caused by inconsistencies in the coordinate systems selected in steps B.1 and B.3. The coordinate systems selected in B.1 and B.3 must be the same to avoid such cracks.

  3. Q: How to assign the geographical coordinates?
    A: Adding a metadata.xml file to the archive file with coordinate information description. Usually the metadata file is placed at the root of the archive directory and its file format is as below.

<?xml version="1.0" encoding="utf-8"?>
<ModelMetadata version="1">
        <!--Spatial Reference System   Only ENU coordinate system can be supported. The two numbers after the ENU are the latitude and precision of the ENU coordinate system origin.-->
        <SRS>ENU:22.64434,114.06046</SRS>
        <!--Origin in Spatial Reference System  The origin coordinates of uploaded model in the ENU coordinate system -->
        <SRSOrigin>0,0,0</SRSOrigin>
</ModelMetadata>
  1. Q: After the context capture model is well uploaded and converted, when the .ab outcome is imported into the development platform, the model location is not accurate as expected. How to solve it?
    WeChat Image_20191010174702.png
    A: You need to manually enter the center coordinates (SRSOrigin) of the xml into the "local translate" in the final_report.json file.
    20190910141650.jpg
    201909101416501.jpg