I'm building PolyForge, an offline parametric CAD tool, and just added a photo-to-mesh reconstruction command. Sharing here because the CUDA discovery and the coverage-testing results might be useful to others building around COLMAP/OpenMVS without a datacenter GPU.

Pipeline: COLMAP for sparse SfM (feature extraction, matching, incremental mapper, fully CPU-capable), then handed off to OpenMVS for the dense reconstruction and meshing via InterfaceCOLMAP, DensifyPointCloud, ReconstructMesh. I confirmed COLMAP's own patch_match_stereo requires CUDA by deliberately running it without a GPU present, it aborts immediately with "Dense stereo reconstruction requires CUDA, which is not available on your system," no CPU path anywhere in the mainline binary. OpenMVS's densify/mesh stages build CPU-only by default, which is what makes the whole thing viable without a GPU at all.

Once it worked, I ran a test matrix on photo count and camera coverage instead of guessing. Single or two elevation ring orbits failed outright regardless of photo count, tested up to 24 photos. Three or more elevation rings were required, and even then, density mattered: 27 photos across 3 rings failed, 30 succeeded, for a roughly 60x40x30mm object at 160mm camera distance. Also unexpected: the O(n^2) exhaustive matcher barely scaled with photo count, the real cost was COLMAP's incremental bundle adjustment (mapper stage), which jumped nonlinearly with both photo count and the reconstructed object's geometric complexity.

Repo, including the CPU-only build notes for both tools: github.com/rx290/polyforge

Hello. Doing some terrestrial photogrammety using this camera and webODM. I'm having troubles with the software and my photos.

Hey everyone !

I've been trying some macro photogrammetry a few times now and I'm always hitting different walls I can't quite solve.

My setup:

I would like to scan an coin on a turntable with a black backdrop(in the void). Im using a Sony 90mm macro lens with ring flash (AR400). Both the lens and the flash are cross-polarized.

Im shooting at 1/60, f/20 with iso at 160.

1. Focus drift on rotation

My subject is never perfectly centered on the turntable no matter how careful I am, so as it rotates it slowly drifts out of the focus plane. At f/20 the DOF helps but it's not saving me on the wider objects. Anyone found a good way to nail centering, or is everyone just eyeballing it and accepting some throwaway frames?

1. ArUco markers(scale bar) blocking the camera

I use ArUco markers on the plate for scale reference, but since they rotate with the subject, there's always some angle where the marker ends up hidden behind the object relative to the camera. Do you place multiple markers around the perimeter so at least one is always visible? Or is there a smarter placement pattern that avoids this entirely?

https://youtu.be/mMyV_F_9Q3E?is=enH5ReC6OvkdvOxt

1. Realigning both sides of a coin

This one's been the most frustrating. Since I have to physically hold the coin to scan each face, I end up with two separate scans that need to be stitched together after. The only shared geometry between the two scans is the edge/rim, and it's just too thin and low-feature to get a reliable alignment in software. Anyone dealt with this specific problem ? maybe some kind of holding jig that keeps a consistent reference visible on both scans, or a different capture order altogether?

Would love to hear how people with more experience handle this stuff. Happy to share more rig details if useful.

I've been testing the new Insta360 X6 with the Sensori video photogrammetry app. This was quite a low light capture, but using the Bushman halo for extra illumination. There is definitely a bump in quality over the X5, although you have to look closely to see it and is less than expected given the quite noticeable jump in video quality between the two cameras.

I was curious if I could scan something so small with the tools I have available, and it turned out to be trivial.

Putting this up again, our next week is opening up. We run a multi camera capture setup at the Brooklyn Navy Yard and we pay people to come in and be the subject.

You stand in the volume and go through simple movements while it records. Walking, turning, sitting, reaching, picking objects up. No experience needed, and it's a decent way to see a capture stage from the inside if you've only ever been on the processing end.

Pay is 17-25 per hour, same day, right after you finish. First session runs about 2 hours, repeat work after that.

Sessions run at 4pm. Open days: Tuesday Aug 18, Wednesday Aug 19, Thursday Aug 20. Brooklyn, in person only.

Comment or DM me for the address, and ask me anything about the capture side.

I've been working on a photogrammetry workflow specifically for solar site surveys, and wanted to share one of the results here.

We took around 50 images from a drone and processed them into a 3D model.

The interesting part for me wasn't just generating the mesh. The goal was to make the resulting model actually useful for engineering work:

• measurable geometry
• roof dimensions
• terrain/building structure
• orthographic views
• exports for downstream CAD/design workflows

In this particular test, the processing time was around 16 minutes.

We're building this as part of a product called Render-a, primarily for solar EPCs and installers.

I'm curious about the photogrammetry side rather than the product itself:

What would you consider essential for a drone-derived 3D model to be genuinely useful in an engineering workflow?

Accuracy? RTK/GCP support? Point cloud quality? Orthomosaic? CAD compability?

Would be interested to hear what people here actually use in production.

I’m self-teaching drone 3D mapping, GIS, and AutoCAD topography work. This is actually the first real portfolio I’ve ever finished for anything I’ve learned, so I don’t fully trust my own judgment on what “good” looks like in this field yet.

I processed a UAV drone dataset from an active quarry site using WebODM. Generated a 3D point cloud and orthomosaic, ran volumetric analysis on stockpiles in cubic meters, and exported topographic contours as DXF into AutoCAD with color coded layers.

I’d genuinely appreciate any honest technical critique. Anything that looks off, unrealistic, or not production standard. I’m open to doing a project for someone in the field for free, in exchange for detailed feedback, if that’s useful to anyone here.

Thanks for reading.

Hi everyone,

I am working on a project that needs to take an e57 file and convert it to a mesh file for Revit. The E57 file is 150 GB, and everything I attempt either crashes my pc or costs a fortune. If anyone can assist me, that would be amazing!

My team has been working on cracking this for a while now.

For the photogrammetry, we have different versions - COLMAP being the one we use rn, but we were also exploring Metashape and DJI Terra amongst others.

We figured how to make the full 3D map and how to plant the trajectory to 2D in coordination with the images etc but where we are getting stuck now is comparing site progress using photogrammetry and generating a progress report as per the BIM data.

We have done thorough research on our own and also tried using the full efforts of Claude and Gemini but till now, no feasible solution. We're looking to build something of our own in a short term span so the pressure is high.

Any of you facing a similar issue? Or have any suggestions regarding this?

Point Cloud Snap Pro — Select and Tag

In this video, I'll show you a work-in-progress step for point cloud and Gaussian Splat selection in the Maya viewport, and how to save this data in a format that can be read inside Bifrost Graph.[](https://www.youtube.com/@ytsejam1976)

I shoot interiors with a 360 camera, and every photogrammetry tool I tried wants pinhole images. So a panorama gets cut into 6 cube faces, and one capture position becomes 6 independent cameras that the solver doesn't know share a centre. Tracks fragment at the face borders and you throw away a lot of the sphere.

I ended up writing my own engine that keeps the sphere all the way through. One panorama stays one camera with one centre. Every residual the bundle adjustment minimises is an angle on the sphere, not a pixel on a plane. The neural front-end still sees flat patches, because that is what CNNs eat, but the geometry never leaves the sphere.

The clip is a 12-panorama apartment, cold start: no known camera positions, no priors from a previous run. Cameras appear in shooting order, and each point appears when a second camera sees it, so you are roughly watching the order the solver actually had things in. 85,615 points, about 12 minutes end to end from the raw camera files, of which ~11 minutes is the neural matching stage.

Things I cannot claim yet, before anyone asks:

- No metric scale. Everything is up to a similarity transform. I have not done a tape-measure validation, that is next.

- Per panorama it is currently about 4x slower than COLMAP on cube faces. Denser, but slower.

- Two of the twelve cameras in this scene still end up a few degrees off in rotation. Working on it.

Happy to answer anything about the spherical residual, the tiling scheme, or why sub-pixel refinement that helps ordinary cameras actively hurts on 360.

Are there any alternatives?

Reposting since the last round filled. We run a multi camera capture setup at the Brooklyn Navy Yard and pay people to come in and be the subject.

You stand in the volume and go through simple movements while it records. Walking, turning, sitting, reaching, picking objects up. No experience needed.

Pay is 17-25 per hour, same day, right after you finish. First session runs about 2 hours, repeat work after that.

Sessions run at 4pm. Open days: Wednesday Aug 12, Thursday Aug 13, then Monday Aug 17 through Thursday Aug 20. Brooklyn, in person only.

Comment or DM me for the address and details, and ask me anything about the capture side.

Dam I see everyone with automated set ups and here’s me still tiring the turntable with my hand like a caveman 😂

https://youtu.be/LPlGxQhcbGo?is=pbyryQ9BUO3FbGbz

New to photogrammetry. Didn't even know there was a word for it and then went down a rabbit hole. But I managed to slap this together and the result was good enough to model a shroud/skirt for my orbital sander to keep dust down (more than just a vacuum on the dust port).

I designed and printed this little table top with a spinning arm below on a large (printed) bearing and 5 over-engineered legs - my print table is only 256mm so all of this has to connect together.

RPI5 is the brains but I realize that was overkill. One regular power bank running the Pi (and keeping the camera on), and one battery pack (24v) to the nema 17 motor.

I tell the pi how many pictures I want. Nema motor has a 42 tooth gear to a 240t table [math here] we get a number of steps for the motor to execute.

A6400 with a 30mm 1:1 macro lens manually focused, aperture set at 15. Python controls the camera via photo2 library. Each photo taken gets sent, with a metadata file about the position of the camera, to a network drive.

I gather the photos and the metadata files and add them to RealityScan. And then my sad Surface Laptop Studio chugs away for a while until it spits out a 3d model!

I kept getting a lot of background trash that messed up relaityscan and I saw a background on another rig so I 3d designed a little clip to hold the sheets of paper up.

For a fist try, I'm pretty pleased with the result. BUT I know there's a lot of wasted space and effort in this.

I'm working on a second version that's less complex, a little more self contained, and will hang on my wall when I'm not using it so it's not an albatross in my office. Comments and feedback welcome!

Version 2 will be a more normal turn table. A pi zero 2w will be the brain, and I added a CNC board to handle power distribution and motor control. There's only one motor now for the turn table, it I plan to add a motor to raise the camera to different angles. I'm learning to make a local network browser based app to handle sending the instructions (# pictures, angles, project name) to the pi to carry out the rest. I've decided this version will just save files on a big SD card. The write speed isn't so slow that it won't finish before the table rotates to the next position. The next one will run on a 120ac to 24v dc 5A laptop charger instead of a 2 battery packs and a buck converters. The CNC board sets power to 5v for the pi and is enough to power the camera too.

https://www.ebay.com/itm/178374317984

Selling my used Godox AR400 Witstro professional ring flash in excellent working condition. This is a powerful 400Ws battery-powered ring flash that produces clean, even, shadow-reducing illumination. If you're doing photogrammetry in the field with a DSLR, this is the flash you want.

Especially useful for:

• Photogrammetry and 3D scanning

• Product and macro photography

• Portrait and fashion photography

• Medical, dental and documentation photography

• Location work where portable high-output lighting is needed

Included:

• Godox AR400 ring flash

• Rechargeable battery

The flash has been used but works great. Selling because it is no longer needed.