Photogrammetry

Photogrammetry is a technique through which you can extract 3D information from photographs. By extensively photographing an object from all sides, you can use software like Polycam or Abound to create a 3D mesh from these photo's. This mesh can then be imported into 3D software like Blender, and can be rendered using the photo's as textures. 

Polycam

Polycam is an app that can use photogrammetry, gaussian splatting and LiDaR (with apple iPad/iPhone Pro models) to make 3D captures. It can be used for free and paid. The free version offers 20 object scans with a maximum of 100 images per capture. It also offers a free gaussian splatting tool. The paid version has unlimited scans and images per capture. Here's an overview of functions, both free and paid: https://poly.cam/pricing

Unlike in other software, the Polycam app helps you make scans. While you are circling around an object, the app takes photos for you and tells you when to slow down. It also shows you how much photos you have left. When in LiDaR mode, it overlays and previews the mesh that its building in real time. After you're done capturing, it uploads your images to Polycam where it builds your scans. You can view and download them online.

In general, use LiDaR when scanning spaces or environments and use photogrammetry for objects. Gaussian splats may work in scenarios where the object you're scanning has specular, fuzzy or translucent qualities. It is harder to convert into a mesh, however. A short description of when to use LiDaR vs Photogrammetry can be found here: https://www.youtube.com/watch?v=gZ6AWrzIx6c&list=PLqnRz-4Awhm7MXTpkgq9paJLC3ONJEBUX&index=1

Working with LiDaR, photogrammetry and guanssian splatting in Polycam:

Here's a tutorial detailing how to work with LiDaR in Polycam: https://learn.poly.cam/hc/en-us/articles/27419935601940-Creating-LiDAR-Captures

For photogrammetry, see this tutorial: https://learn.poly.cam/hc/en-us/articles/27425185907348-Creating-Photogrammetry-Captures-in-Object-Mode

And for Gaussian splatting: https://learn.poly.cam/hc/en-us/articles/27740818315668-How-to-Create-Gaussian-splats-on-Polycam-mobile

Taking your scans into other software

If you want to process your scans into software like blender or unity, Polycam has great tutorials on these topics on YouTube.

Blender: https://www.youtube.com/watch?v=1HxJiwihi6g&list=PLqnRz-4Awhm7MXTpkgq9paJLC3ONJEBUX&index=9&t=105s

Unity: https://www.youtube.com/watch?v=DEbDsxETQuE&list=PLqnRz-4Awhm7MXTpkgq9paJLC3ONJEBUX&index=14

Find more software use cases here: https://www.youtube.com/playlist?list=PLqnRz-4Awhm7MXTpkgq9paJLC3ONJEBUX

Abound

Abound werkt in browser (dus beschikbaar voor mac & windows) met een limiet van 20 Photo Scans & 100 images per scan. 

RealityScan

RealityScan (previously Reality Capture) is software used for photogrammetry. RealityScan offers a mobile app for iPhone and Android and software for desktop that’s only available for Windows. Both are free to use.

Pros and cons of mobile vs desktop

Mobile:


Desktop:

 

To start using the desktop app you have to download the Epic Games Launcher.  From there, navigate to RealityScan, and download and install.

Tools to aid in photogrammetry

Circular polarisation filters

Anti-reflective coating spray

Gaussian Splatting: online and local

This is an experiment in progress. Current status: We've succeeded in fully generating the splat from the Blender interface, on Windows. See option 1 Sky Splat below.

Gaussian splatting offers an interesting alternative to photogrammetry for specific use cases, particularly where real-time rendering, photorealistic results, and the ability to capture reflective and transparent surfaces are necessary. There are lots of online options for Gaussian splatting, both paid and unpaid. Kiri Engine seems to be a very complete suite and now has the option to make meshes out of splats, for use in for instance Blender in the paid version.

If you don't want to rely on external systems, you can make Gaussian splats (and photogrammetry) yourself on a somewhat beefy computer. The main difference between splats and photogrammetry is that splats make point clouds, no meshes. This makes the renders lighter but harder to manipulate. Also see the Tested video for this discussion.

For all online platforms (paid or unpaid), please be aware of your data and privacy! 

Gaussian Splatting locally 1: with Sky Splat

Full workflow from video to splat runs from within Blender, uses the Colmap tool for making the splats. Tried on Windows.

Additional notes to the video above:

Install the skysplat plugin. Plugin appears in the plugin bar on the right (press N).

Tab 1: open video. This will extract stills from the video.

Tab 2: Colmap. First under Colmap settings, enter the location of the Colmap folder (Colmap.exe in the Bin map). Then:

Tab 3: run brush training. When opening the brush training on Windows, this only works when Blender is opened with Administrator rights. If it's not this step will result in an error, or hangs on starting the training.

2: with LichtFeld

Open source splatting tool, not yet tested

https://lichtfeld.io/ 

https://github.com/MrNeRF/LichtFeld-Studio

LichtFeld needs a more detailed dataset than 'just' the images, it requires "undistorted images + pointcloud + camera locations". The pointcloud and camera locations can be generated using the Colmap process above, or from Reality Scan.

3: with PostShot (tried first, no longer free)

March 2026 Update: Can't export to .ply in the free version of Postshot anymore...

Workflow in Postshot:

There are plugins for

Below: the same chair model in Postshot and Blender

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Postshot

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.ply in Blender

Compared to local photogrammetry (RealityCapture)

We've used the same source video for a render in RealityCapture. This render took about three minutes and shows one of the problems with photogrammetry: shiny objects become invisible. You can fix this by using a polarizing filter over your lens.

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In RealityCapture

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.obj imported in Blender

Full workflow: filming->After Effects->Reality Scan->Postshot->Octane (Cinema4D)

This vid has a full workflow with great tips on every step. After effects is used for extracting photos from the video, Reality scan for aligning the photos, Postshot for generating the splats, and Octane for rendering them in Cinema4D.

Re-lighting the scene starts here: https://www.youtube.com/watch?v=OzUxL_UDMTk&t=3436s 

Thoughts on using Gaussian Splatting

As long as Gaussian splatting does not easily convert to meshes, it's use in live 3d engines might be limited. It might be more applicable to pre-rendered applications, where you have can re-edit the camera from the original recording. Change angles, change camera movement, etc. With the newer options to change lighting this will become even more relevant.

More Splatting stuff

Turning a Gaussian Splat into a game

Playcanvas is an open-source online splat viewer. It can clearly do more than just view them, as you can walk through them as if it's a game environment. And of course: you can turn it into a game: https://blog.playcanvas.com/turning-a-gaussian-splat-into-a-videogame 

Editing splats with SplatShop

Open source, with VR editor.

Edit splats, remove parts, move parts, clone parts, etc.

https://github.com/m-schuetz/Splatshop

Re-lighting Splats

Apparent you can re-light Splatted scenes. One option menioned is in the Octane rendering engine, another is using a UE5-plugin called Volinga

Re-lighting in Blender

Using the Kiri Engine plugin from here: https://github.com/Kiri-Innovation/3dgs-render-blender-addon

Manual and quick guides for Kiri Engine: https://www.kiriengine.app/blender-addon/3dgs-render

Various tutorials on Gaussian Splatting

importing .ply gaussian splat in Blender

Core principles of photogrammetry

Image quality, Information overlap, Subject coverage

Very good guide: Photogrammetry Basics

Screenshots below were taken from this Unreal Engine YouTube seminar

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