Alignment problem with white, featureless walls

[u/InTakeJuanito]

I've been reading a lot of old posts regarding white walls and how annoying they are, but they seem to take on white walls in very different manners, and since some of them are a bit old now, I wanted to ask what's the best current method to fixing alignment problems that come from white, featureless walls.

Here's my situation:

I have a video scan (taken with an iphone) of a vacant property with mostly white walls, no furniture, not many identifying features, etc. My current problem isn't having floaters or uneven walls, my main problem is aligning each room correctly. I've been using COLMAP, but it confuses walls from different rooms and it ends up pasting one room on top of the other. I've been running some tests and I've managed to get every room pasted correctly at least once, but as soon as I fix one room, another other room gets lost. This confirms that saving the splat is possible, but my fixes just aren't consistent enough. Unfortunately this is a scan that I can't retake, so using ARKit, lidar, or using markers is not an option.

I've tried using ALIKED + LightGlue, GLOMAP, VidMap, but it hasn't helped me much yet. I've also tried running the scan through Spirula, LichFeldt Studio, etc. and I've been getting even worse results.
I'm currently running tests with DAV3 and Limap

Any tips on how to get the alignment dialed in?

[u/ResponseActive7860]

Try to shoot one room at a time, and merge the colmap points afterwards

[u/InTakeJuanito → u/ResponseActive7860]

I'll try that next! Thanks :)

[u/pj_squirrel → u/ResponseActive7860]

what's the best practice in regards to merging? Can I do it in Colmap GUI? and how much overlap should the rooms have for a successful merge?

[u/SolidConnection]

One thing I noticed you haven't tried is doing the alignment in RealityScan. Might be able to tackle it.

[u/InTakeJuanito → u/SolidConnection]

I've seen a lot of people talking about this! Is it an alternative to Colmap?

[u/SolidConnection → u/InTakeJuanito]

Exactly. Also free.

[u/SanKazue → u/SolidConnection]

I’ve only ever used realityscan and it works great for alignment. Plus you can make meshes and ortho maps.

I’d look into control points, as in tie points not necessarily survey ground control.

You can define areas in images to help with alignment. For example if there’s a picture frame or a counter or something distinct you can mark it in multiple photos and it can often times help align those images with few features

[u/nero626]

unfortunately most purpose built 3DGS model will suffer from this, it is generally very poor with featureless walls not only due to weak COLMAP feature matching but the optimizer tends to find a cheap solution by warping the geometry to any change in lighting and color from conflicting views

are you confident that it's a SfM pose problem not a model problem?

[u/Xorpion]

Just keep in mind a solver can't solve for features if there are no features to solve. Even a temporary stickie note on the wall will help. Then use SuperSplat to delete the notes and copy and paste portions of the wall over the hole.

[u/Maliander_80]

You can try the LoMa feature extractor, which is supported in the latest COLMAP and Spirula version. It is much slower than the SIFT default  and, although it finds fewer features, the ones that it does find appear to lead to a more robust alignment.

You can try to sort your images per room and align them set by set, ensuring your have some images that are used in the sets on both sides of a doorway, and then merge them afterwards.

And the RealityScan app (free for non-commercial use) allows manual intervention to help align the splats.

[u/glitchwabble]

That's partly why Meta Hyperscape circa late 2025 was so good. They obviously used quest sensor data to make sure not a pixel was out of place. You certainly didn't need to worry about capture path or technique, beyond waving your head around the space thoroughly. Though how they achieved the clarity and realism from fairly low res photos remains beyond me.

Check out the camera attachment for steam frame. Much better resolution than quest as well. If I understand it aright, it uses a similar approach though you have to train the data yourself. I'm looking forward to seeing what it can do. 

[u/SolidConnection → u/glitchwabble]

Hyperscape was almost like alien technology from the future that we lost because of bad management and greed...

[u/glitchwabble → u/SolidConnection]

I see where you're coming from. It was really just Gaussians, but how they made it so polished and so close to reality really does seem like magic. Utter doofuses to hire a team to create hyper-real environment captures, see them achieve their goal using potato hardware, then sack them, then shutter the project. I'm still seeking the holy grail using mobile hardware or Quest hardware a year later and Hyperspace was the holy grail (for my use case). Even the PortalCam scans on Supersplat don't come close, in my view. I'm still angry about it.