How to export your RealityCapture project for Nira

Also see How can I achieve the best quality textures from RealityCapture?

First, a note on georeferencing:

To best utilize all of Nira's georeferencing features, it is recommended that you export your files using georeferenced coordinates. If you plan to use georeferenced coordinates, you'll need to determine an appropriate coordinate system for your project. Here's how:

• Choose a UTM Zone if you're not sure which coordinate system to use:

Simply drag one of your project's photos into the UTM Zone Identification webpage and make note of the UTM Zone displayed. You'll use it in one of the steps below.

• If you already have a preferred coordinate system:

Be sure it's cartesian. To check this, look up the EPSG number here: https://epsg.io. Ensure that it includes "Coordinate System: Cartesian 2D CS". For example, the page for EPSG:28992 confirms that is cartesian, whereas EPSG:4326 is not. If your preferred coordinate system is not cartesian, you should use a UTM Zone instead -- see the first bullet point above to learn how.

To Set the RealityCapture Project Coordinate system

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1. WORKFLOW Tab

2. Application : Settings button

3. Project coordinate system ... button 

4. Search for and pick an appropriate coordinate system from the list. If you're not sure what to choose, read the tips at the beginning of this page.

5. Click Select.

6. Repeat steps 3, 4, and 5 for the "Output coordinate system" setting. It's important that both "Project" and "Output" settings are set to your chosen coordinate system:

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Important Notes about Coordinate System settings

  • As shown above, both the Project coordinate system and Output coordinate system MUST match each other. If they do not match, RealityCapture will export invalid .obj files.
  • The coordinate system settings must also match your actual data. For example, if you set your Project and Output coordinate system to WGS 84 / UTM Zone 17N, this must correspond with the geographic region where your scan data was captured. If it doesn't, RealityCapture will export invalid .obj files. If you're not sure what coordinate system to choose, please follow the "First, a note on georeferencing" section at the beginning of this article.
  • These settings must be correct BEFORE exporting your model and camera data. If you realize these settings are incorrect, please correct the settings, then re-export your data.

Direct Upload to Nira:

RealityCapture supports direct upload to Nira. To get started with it, first set your coordinate system using the instructions above, then follow this guide.

Alternatively, to manually export and upload:

Export model and Textures:

Reality Capture > MESH MODEL: Export > Dense Mesh Model...

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Provide a file name and choose Wavefront obj (*.obj) as file type.

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It is very important that your export settings match exactly as you see in the screenshot below.  Items highlighted in red are settings that have been changed from the defaults.

 

Save mesh by parts : Yes

Export vertex colors : No

Number format : Decimal 6 (trimmed)

Coordinate system : Shifted project output

 

Export Camera alignment data:

Reality Capture > Alignment > Export > Registration > Internal/External camera parameters

Provide a file name and click Save

Be sure to choose Shifted project output

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Upload all of the following files to Nira:

  • The .rcInfo file (required for georeferencing)
  • Photo files (jpg, png, or tiff)
  • Camera CSV file
  • Textures (png)
  • .obj and .mtl files

After uploading, you’ll have all of your photos (and orthomosaics if created) available within the Show Photos… button, and GPS coordinates will be shown on the asset's preview page and within callout dialogs.

 

 

Shifted project output vs Project output

Both Shifted project output and Project output is compatible with Nira and will provide all the necessary data, including georeferenced information.

  • Shifted project output will export mesh data centered at the coordinates 0, 0, 0 and will include the georeferenced offset coordinates in the rcinfo file.  Nira will interpret the mesh coordinates at runtime and produce the geocoordinates by referencing the rcinfo file.  The primary benefit of Shifted project output is that OBJ data is compatible with all OBJ viewers for both viewing and editing.  However, a drawback is that you cannot upload two separate and discontinuous assets processed in RealityCapture or other photogrammetry tools into a single asset without manually adjusting one the position of one of the projects.  
  • Project output will export an OBJ file with the georeferenced coordinates baked into the mesh coordinates.  The main advantage is that you can seamlessly merge multiple projects into a single Nira asset without manual effort (i.e., no need to manually move anything into position).  However, the downside of Project output is that the OBJ data is generally incompatible with most third-party viewers and editors.

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