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This is due to the method of data acquisition. My company also uses cesium (in the browser) for visualization at sub cm level for inspection. Our quality bar is

by tinco 6y ago

This is due to the method of data acquisition. My company also uses cesium (in the browser) for visualization at sub cm level for inspection. Our quality bar is that inspectors have to be able to inspect the grain of the grout between the bricks. We acquire the data in 3 modes for high buildings, we do low altitude fly over with the 2m drone, then we do facade with the regular drone, and finally we shoot from the ground. We only do ground based lidar, but aerial lidar is improving so maybe that's next. The rest is all high detail photos fed into photogrammetry. The final results look perfect in cesium, some thin rails might not show up, and windows get a bit funky, but the geometry and the textures load in without a hitch, really cool technology that's so simple in the basis that we built an alternative viewer in Rust+WASM in 3 weeks.

StavrosK 6y ago
Wait, if the technology is so simple that you can build an alternative viewer in 3 weeks, what are they selling? Is it the data format?
- asutekku 6y ago
  They’re selling it so you don’t have to get it by yourself.
- sbarre 6y ago
  3 weeks for a prototype 3 months for an alpha 3 quarters for a production release. You know how engineering estimates work... ;-)
- tinco 6y ago
  They've got a whole bunch of features in their viewer, making a feature matching viewer would take years. The basic technology is a tree of JSON files describing what models or other JSON files to load for regions of space. So the nodes are JSON files and the leaves are 3d models basically. There's a simple algorithm that you give your current perspective (i.e. where you are in space, and what direction you're looking in) that will walk the tree and decide what models will be in your field of view and which won't be, and at what distance (which decides the level of detail). Then the last step is simply downloading those models, while at the same time evicting irrelevant 3d models from your gpu. They hand rolled an entire high performance 3D engine in Javascript, which is a big challenge in and of itself. We cheated by using WASM and a high performance programming language, making the 3D engine part trivial. Likewise, I'd be surprised if it took them more than a week or two to get their initial proof of concept working in Unreal Engine. Oh and I believe their business model is/was to sell hosting and processing for the 3D models. We've been paying them a couple hundred per month just for this service.
  - StavrosK 6y ago
    That's helpful, thank you!
maxhq 6y ago
Off topic, but: would you mind telling which software you are using for the photogrammetry?
- reactive001 6y ago
  Having worked at a company with an identical premise, Reality Capture (because it's faster) or Bentleys
  - tinco 6y ago
    Nice! where did you work?
- tinco 6y ago
  We're using Metashape and Reality Capture. We used to use Bentley, but they've got unethical business practices so we're avoiding them now. Metashape has really good licensing, and their software runs on Linux and is easy to integrate into processing pipelines, also they've got a big featureset. Reality Capture was super expensive, though that has seemingly changed now that they're bought by Epic, so we might reconsider our strategy there. They make better use of hardware, making them faster, and their resulting models look great. Their licensing was so expensive that we just couldn't afford switching all of our processing to RC.
  - andybak 6y ago
    > We used to use Bentley, but they've got unethical business practices Go on. I'm curious now.
    - tinco 6y ago
      You can google a bit about Bentley Connect charges, we were not the only ones who called their sales reps in a panic. https://community.spiceworks.com/topic/2129583-gathering-info-class-action-lawsuit-bentley-systems-for-over-usage-charge https://community.spiceworks.com/topic/2129583-gathering-inf... If you can get a good deal with them it's probably fine, and we only talked to nice people there. But we're still on limited runway, we can't deal with random $20k invoices, even if a nice sales rep reverts the charge when called.
X6S1x6Okd1st 6y ago
Could you use a technique like this to do facade inspection as mandated in nyc? I just happened to watch "how to with John Wilson" S01E02 which was talking about how scaffolding is put up everywhere in nyc because the facade needs to be inspected for loose bricks every 5 years

by tinco 6y ago

StavrosK 6y ago

Wait, if the technology is so simple that you can build an alternative viewer in 3 weeks, what are they selling? Is it the data format?

asutekku 6y ago
They’re selling it so you don’t have to get it by yourself.
sbarre 6y ago
3 weeks for a prototype 3 months for an alpha 3 quarters for a production release. You know how engineering estimates work... ;-)
tinco 6y ago
They've got a whole bunch of features in their viewer, making a feature matching viewer would take years. The basic technology is a tree of JSON files describing what models or other JSON files to load for regions of space. So the nodes are JSON files and the leaves are 3d models basically. There's a simple algorithm that you give your current perspective (i.e. where you are in space, and what direction you're looking in) that will walk the tree and decide what models will be in your field of view and which won't be, and at what distance (which decides the level of detail). Then the last step is simply downloading those models, while at the same time evicting irrelevant 3d models from your gpu. They hand rolled an entire high performance 3D engine in Javascript, which is a big challenge in and of itself. We cheated by using WASM and a high performance programming language, making the 3D engine part trivial. Likewise, I'd be surprised if it took them more than a week or two to get their initial proof of concept working in Unreal Engine. Oh and I believe their business model is/was to sell hosting and processing for the 3D models. We've been paying them a couple hundred per month just for this service.
- StavrosK 6y ago
  That's helpful, thank you!

maxhq 6y ago

Off topic, but: would you mind telling which software you are using for the photogrammetry?

reactive001 6y ago
Having worked at a company with an identical premise, Reality Capture (because it's faster) or Bentleys
- tinco 6y ago
  Nice! where did you work?
tinco 6y ago
We're using Metashape and Reality Capture. We used to use Bentley, but they've got unethical business practices so we're avoiding them now. Metashape has really good licensing, and their software runs on Linux and is easy to integrate into processing pipelines, also they've got a big featureset. Reality Capture was super expensive, though that has seemingly changed now that they're bought by Epic, so we might reconsider our strategy there. They make better use of hardware, making them faster, and their resulting models look great. Their licensing was so expensive that we just couldn't afford switching all of our processing to RC.
- andybak 6y ago
  > We used to use Bentley, but they've got unethical business practices Go on. I'm curious now.
  - tinco 6y ago
    You can google a bit about Bentley Connect charges, we were not the only ones who called their sales reps in a panic. https://community.spiceworks.com/topic/2129583-gathering-info-class-action-lawsuit-bentley-systems-for-over-usage-charge https://community.spiceworks.com/topic/2129583-gathering-inf... If you can get a good deal with them it's probably fine, and we only talked to nice people there. But we're still on limited runway, we can't deal with random $20k invoices, even if a nice sales rep reverts the charge when called.

X6S1x6Okd1st 6y ago

Could you use a technique like this to do facade inspection as mandated in nyc? I just happened to watch "how to with John Wilson" S01E02 which was talking about how scaffolding is put up everywhere in nyc because the facade needs to be inspected for loose bricks every 5 years