ITwin Capture Modeler Presets
iTwin Capture Modeler includes some Presets (low level settings) that control all aerotriangulation processing settings which can help to improve the results of the aerotriangulation under specific conditions.
The presets can be accessed from the Settings section of the Aerotriangulation Definition dialogue as shown below:
When you have clicked o the icon you will need to navigate to the following location depending on which edition of iTwin Capture Modeler is installed:
ITwin Capture Modeler:
C:\Program Files\Bentley\iTwin Capture Modeler\data\Presets\AT
iTwin Capture Modeler Center
C:\Program Files\Bentley\iTwin Capture Modeler Center\data\Presets\AT
ITwin Capture Modeler aerotriangulation presets currently available:
· CC18 Alternate engine
· CC8 Legacy engine
· CC20.1 engine
· CC20.1 maximum position metadata confidence
· CC2023 position metadata constraint (tech preview
· Do not check rigid registration reliability
· Keep all components for adjustment
· Use pose metadata for SfM
We would recommend that that before attempting to use any preset an aerotriangulation should be completed using the default aerotriangulation engine /settings. If the results from this are not satisfactory, then using a preset may be the right solution to get better results.
A Preset can be used under the following conditions:
CC18 Alternate engine:
Use the "alternate engine" of update 18 when "computing" poses; this is slow and not very scalable but very robust.
CC18 Legacy engine:
Use the Update 18 "legacy engine" when "computing" poses: this is the former engine used in all versions prior to Update 18 and is not considered to be as robust as the current one.
CC Update 18 presets are available for users that have upgraded from earlier versions and prefer the results of the aerotriangulation in those versions.
CC20.1 engine:
Mainly useful if you do not wish to use the "new Adjust poses" engine. This is fast and accurate but much less robust and results in poorer initial poses than the current one.
It is recommended that the CC20.1 engine is used for example when an aerotriangulation is run on another aerotriangulation, where a good result has been achieved but, you want to finely adjust the result on Ground Control Points and to continue using the default engine most of the time (with no preset).
CC20.1 maximum position metadata confidence:
To be used when you are confident that your GPS is very good, and you consider that the engine has not adhered to your GPS as strongly as you would expect.
CC2023 position metadata constraint (tech preview):
This is a new version of the previous preset. It is stronger than using no preset but more robust than the "maximum confidence" one.
The “Maximum confidence" or "2023 metadata constraint" are not only for use on bad aerotriangulation results, but they are also good for any aerotriangulation that the users want to have a stronger adherence to the data’s GPS information.
Do not check rigid registration reliability:
This enables the rigid registration on position metadata to occur even when it has failed because of inaccurate GPS information or poor AT result.
This preset can be used when the GPS info is bad (or weak) with respect to the scene size, but you still want it to be used at least for geo positioning. A typical use case for this would be a is a small scene, such as a trench.
Keep all components for adjustment:
Only useful when the position policy is set to "keep" or "adjust within tolerance", it allows the process to keep several disconnected components and not just the largest one.
Use pose metadata for SfM:
This preset may improve the robustness of the engine when you're confident that your input poses are good, and you fear that the engine connects some cameras poorly because of repetitive patterns or ambiguous areas.
A typical case where "Use metadata for SfM" may be helpful is when you must deal with two sides of an asset that look similar (for example on a bridge or building, etc...)
Note:
Additional Aerotriangulation presets may be provided by the Bentley ITwin Capture technical support team to solve specific issues.