Welcome
Saturday, April 1st, 2023
Adjustment allowance for setting up over a point (can be rough aligned using the laser plummet in the instrument height measurement tool, then fine aligned using the instrument plummet):
@beuckie Do you know if it's possible to mark scan positions on the ground, does the vz have a laser plummet? We know our scan positions with a high level of confidence and mark them out, it's easy for someone to set up a total station over a point later and use them when setting out. Some jobs are part of pre project planning in existing industrial plant, new installs and upgrades need to fit in with old plant, some things get removed, but other components remain, a lot of the existing plant gets obscures visibility when setting out.
A Riegl has a plummet although never used. It also doesn't have to be level so the plummet is rather useless. It's doable but the scanner is heavy (vz400i) so sliding a tribach on a tripod isn't as easy. Also there is no levelling bubble visible in the software so you would rely on the tribach itself.
I suggest you get a real live demo in the field where you check it out. No need and useless imho to mention all sorts of figures. The data tells all the values.
If you want some data, sent me an email on lieven (at) lsbbvba.be and i'll send you some
With my Faro Focus S150+ and SCENE software I use a fixed 2m GPS tripod (carbon fiber). This has the center pole with bubble that allows us to setup the scanner on a nail with a fixed height. SCENE Software will use the scanner position as the highest weight over an targets.
@beuckie Thanks, I'll take you up on your generous offer. Talking to my local rep, Reigl doesn't recommend setting up the instrument over a point, which makes sense, it doesn't have sufficient level compensation accuracy, the tripod would need to be levelled first using a precision carrier, but then the instrument is heavy, so the weight might alter level, so not a good idea, instead control targets are recommended to establish the level plane (at least that's what I've been told, I haven't used the scanner).
Regards,
Peter.
@leegreen There was a problem you were solving here, as your method is relatively unique, I'd be interested to hear more about your workflow and why you developed it.
Cheers,
Peter.
@leegreen There was a problem you were solving here, as your method is relatively unique, I'd be interested to hear more about your workflow and why you developed it.
Cheers,
Peter.
While working on vertical construction sites (BIM) over the past few years, I noticed a new trend where many non-surveyors are performing scans. All were performed without asking for a single control point. Then when their scans don't align they come to the surveyor. So I purchased a Faro Scanner as this was/is the most common scanner I see on job sites being used by others. In my self-learning and conversations with FARO developers, I noticed that SCENE can use the scan position as a weighted target (control point). It is used as the highest priority. Although we currently can't user-define the weighted value in Scene, I believe that with my discussion with developers, it is coming. However, the next question was "How do we set up the FARO scanner over a point precisely, with an easy-to-measure height, while keeping the scanner up high"? With the industry standard lightweight camera tripod, this is impossible, plus this flimsy tripod is very unstable in outdoor conditions. So while thinking outside the box I started using my GPS 2m tripod with the FARO scanner. The aluminum tripods are a bit heavy and baulky. Then I found the all carbon fiber 2m tripod from survey pro-USA. This is much lighter, making it easy to level the scanner over a control point, while being very stable. I also learned that SCENE needs at least three "checks" (for lack of a better term) in order to register between two single scans. These three "checks" can be comprised of any of the following: Scan Position, Tilt Sensor, Sphere, Targets, Planes, etc. The FARO does have a compass, and GPS as "check", however, they are not to be used for accurate positioning, rough only. Therefore I noticed we can use two Spheres and the Scan position (with tilt as backup) or at the very least we can use tilt, scan position, and a single sphere.
Here is a pic of my common sphere configuration between scans, along with 13ft tripod setup. Notice the shortest sphere is on The Marksman This allows me to accurately and easily set up the Sphere over another known position such as nail or cross cut. Helping to strengthen the registration.
@leegreen So you've basically got control scan positions, with rotational alignment determined between scans by spheres, which doesn't require measuring numerous target locations and provided your control points are relatively tight (least squares adjusted), you avoid the lack of loop closure that Scene has, which leads to registration problems, and you don't have to register all your scans at the same time, once you have a network of aligned scans to your control points, they should have accurate rotational alignment. I see you've got the Ricoh Theta camera on top, so you've got short scan times too.
Be careful with Faro's going out of calibration, I'm guessing with your workflow, you'll likely be able to tell when the scanner is starting to drift outside of calibration tolerances.
Cheers,
Peter.
