I'm interested in people'e experience with Trimble GX 3D scanners and how they compare to other brands (for example Maptek 8400, Leica C-10, Topcon GLS-1500, Faro). We're looking at buying one for short-range (less than 200 m) high-accuracy (1 cm vertical) topo surveys.
I highly recommend that you use caution with the shorter range scanners. I used one of the popular models that demoed extremely well at my office. But when I put it into use on stockpiles, I found that out in the bright sun it would only shoot about 1/3 as far as the spec said. It was totally useless. And if you are planning to do topo work on land with low topographic relief your problem will get worse.
It is hard to keep the novelty factor out of one's brain when making a purchase decision for this fantastic technology. Seems that the sales people sometimes don't understand that the end user is expecting to use it professionally and profitably. This is not an overall statement for all dealers, but it is applicable to some.
The combination of much shorter ranges in bright sun and the failure to get returns when the laser angle is low with respect to the surface can be a serious and disappointing problem, especially for one type of scanner technology. I tried twice to scan a large stockpile with a new scanner, and it took a lot longer to scan and produce results than it did to just get out there and do it with RTK and Carlson.
The problem can be exacerbated by the huge volume of data. Not all the software out there works like it should. It is hard to recognize the deficiencies until you really start using it. You can come back with a load of "beautiful data" and spend three days trying to process it. There appears to be a lot of bugs with some of newer scanning software. For example, one software that costs many thousands, will suddenly flip the imagery into a mirror image, and the cad drafter won't even recognize it. I called it in to tech support, but they did nothing, even thought they are now aware of the problem. I wanted to switch to the Leica scanning software from what I had, but to transfer data to their software required a translator that costs several thousand dollars, and the Leica software maintenance charge was huge. The annual support contract for a scanner is high as well--$5,000 and higher.
Bottom line with this stuff, is that jumping into it and making it profitable is not nearly as easy as it looks. The people who make money with this stuff have substantial volume, have bought the best and most expensive systems, and have developed the art of using it. This is not like buying a total station with a laser and going out and collecting some data.
I look for other hardware companies to jump in and come up with lower-cost, more practical scanners in the near future. Leica MS50 seems promising, but more impressive will be what Trimble is getting ready to respond with.
My $0.02 opinion only.
You should also look at a scan where you have vegetation. You will get the top of a lot of grass and other ground cover.
A bigger concern for stockpiles, black industrial roof etc. is the color some of the more popular laser scanners do not work as well shooting "black" items.
As I read this post
I couldn't help but think haw much of this excellent advice could be applied to the latest fadtech..... that being drone photogrammetry. Sure some of the big boys will be able to use it on a small number of projects but Mr Everyday land surveyor may end up being stuck with an expensive toy if he jumps in without a full understanding of just what can be done with the technology..... JUST my humble opinion mind you.