Photogrammetry
- Nathan Dunne
- Rhys Howell
You are now free to follow your normal photogrammetry process, as long as it meets the
Photogrammetry Requirements .
See also our specific tips for the photogrammetry solution you use:
Photogrammetry Requirements
- 1 Input Images
- 2 Camera solve
- 3 ST Maps
- 4 Subject Mesh
- 4.1 Bounding Box
- 4.2 UV Unwrap
- 4.3 Scale
- 4.4 Poly-Count
- 4.5 Export
Input Images
The images produced by Marso with names photogrammetry_XXX.jpg must be used for the solve, otherwise Marso will be unable to detect any cameras that failed to solve.
Camera solve
As well as solving the mesh of the subject, it is important to also get a good solve of the positions of the cameras.
Poorly solved cameras can lead to artifacts in the material measurement later on. We recommend attempting to re-align any bad camera solves or removing those cameras from the 3D solve all together.
ST Maps
Export the ST Map(s) as exr so that Marso can account for any lens distortion.
Subject Mesh
Bounding Box
When drawing a bounding box around your subject for mesh reconstruction, it is important to also include any stands or supports. This additional geometry will ensure that pixels are correctly traced onto this geometry and not onto the subject itself.
Using one of the lower cameras (as shown below) can be a helpful reference to see how much geometry is required to avoid unwanted pixels being projected onto the subject.
Good | Bad |
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Using a Mask Mesh will allow you to reconstruct just the subject, whilst avoiding occlusion issues by providing a Subject Mesh & Mask Mesh
UV Unwrap
For Marso to work the subject mesh must be exported with a UV unwrap. By default, a 3D mesh within a photogrammetry application will not have a UV, so you must either run the texturing process within the application, or do a Manual UV Unwrap.
For optimal UVs we recommend generating the texture at the same resolution or lower resolution than what you wish to output from Marso.
Example: A RealityCapture texture of 1024px can be used to create a Marso texture of 1024 -> 8192px , but Marso may create artifacts at 512px.
Scale
It is essential that the 3D scene is correctly scaled, we suggest using markers to automatically set the scale of a scene within your photogrammetry software.
You can also Re-Scale with Blender
Poly-Count
A high number of polygons in the mesh may cause Marso to exceed the available VRAM on your system. If this occurs, simplify the mesh and reattempt the process. Marso can produce highly detailed normals, even on medium to low poly meshes. See Examples
Export
The mesh should be exported as an Alembic (.abc) file, with cameras and normals enabled. It will be beneficial to follow the export presets below if you are using Reality Capture.
If you are using Agisoft, please follow the details on Agisoft Metashape.