Flow

  1. Compress the obj model, mtl material files and relevant texture files into a zip file.
  2. Log in altizure.com, click Create, select Third-party Model and click Hand-made Model.
  3. On the upload page, upload the .zip file package for conversion. A mail notification will be sent to the registered mailbox upon completion of the conversion.

FAQ

  1. Q: When uploading the exported obj model to altizure.com, what shall we do if the textures or color is missing?
    A: Make sure that the obj can be opened and viewed normally in the browsing software Meshlab. A quick troubleshooting can be conducted on the following aspects. Details refer to Section C of the Import 3ds Max/Sketchup Hand-Made Model with Texture Mapping tutorial.
    • The mtl obj jpg file name contains Chinese characters.
    • The mtl does not match the obj file name.
    • The map has a relative path.
    • If the model itself is not texture mapped, but the color of model is over saturated in bright white, check the mtl file. While if the ka and kd values are 1, you need to change the ka to 0.5 or 0 (ka 0.5 0.5 0.5) or adjust kd to 0.5(kd 0.5 0.5 0.5).
  2. Q: Why there is an upload limit to 50MB?
    A: Because multi-levels of details can’t be built on hand-made models, a single file in large size can freeze page loading and reduce the performance of rendering. Therefore, the number of triangles and the resolution of texture maps should be appropriately simplified before uploading the obj. Try to reduce unnecessary triangles and redundant texture mapping information.
  3. Q: How to add the geographical coordinates to the hand-made model?
    A: You could write a config.json file and compress it with the obj file in the same file. Import the compressed file to the altizure.com. Please refer to the following chapter for config.json file format details.
  4. Q: Which geographical coordinate system can be supported currently?
    A: Now only local and ENU coordinate systems can be supported (details refer to the config.json Definition). The other coordinate systems, such as UTM coordinate system, are considered a local coordinate system. In order to obtain the longitude and latitude correctly, it is necessary to import the models to a planet with a local coordinate system function.

config.json Definition

config.json defines a geographic coordinate system for relevant data that can be used to add geographic coordinates to the obj model.

{
  "srs": "",
  "model_transform": [[1, 0, 0, 0]
                     , [0, 1, 0, 0]
                     , [0, 0, 1, 0]
                     , [0, 0, 0, 1]]
}

The parameters are defined as follows:

  • srs: srs defines the coordinate system in which the model is located. In the case of an empty string"", the coordinate system is a local coordinate system with no geographic coordinates.
    If it is "ENU: latitude, longitude", it represents an ENU coordinate system of the model at this location (latitude, longitude).
  • model_transform: model_transform is a 4x4 row-major transformation matrix that represents how the obj model is transformed to the coordinate system defined by srs. And currently only translation transformations can be well supported by 4x4 matrix.

Examples:

  1. Example of a local coordinate system: This example represents that the origin of the obj model is at (100.2, 200.334, 0) of a local cartesian coordinate system. This case is most common in local coordinate system.
{
  "srs": "",
  "model_transform": [[1, 0, 0, 100.2]
                     , [0, 1, 0, 200.334]
                     , [0, 0, 1, 0]
                     , [0, 0, 0, 1]]
}
  1. Example of the ENU coordinate system: This example represents that the origin of the obj model is at 23.223 degrees north latitude and 122.334 degrees east longitude. At the same time, the coordinate system of the obj model coincides with the three axes of the ENU coordinate system defined at that latitude and longitude.
{
  "srs": "ENU:23.223,122.334",
  "model_transform": [[1, 0, 0, 0]
                     , [0, 1, 0, 0]
                     , [0, 0, 1, 0]
                     , [0, 0, 0, 1]]
}
  1. Example of ENU coordinate system with offset: This example represents the origin of the obj model at (100.2, 200.334, 42.66) of the ENU coordinate system, which is defined at 23.223 degrees north latitude and 122.334 degrees east longitude.
{
  "srs": "ENU:23.223,122.334",
  "model_transform": [[1, 0, 0, 100.2]
                     , [0, 1, 0, 200.334]
                     , [0, 0, 1, 43.66]
                     , [0, 0, 0, 1]]
}