I recently published an article on the benefits of using 3D Laser Scanning on your projects. (This article is no where near as long, I promise!) In it, I touched on the things that you should be looking at getting from your service provider. I think it is worthy of detailing some of the key services available and the potential issues and benefits associated with the services, for those that are looking to use laser scanning.
As a provider of Terrestrial Scanning Services (3D Laser Scanning using a stationary land based scanner) I will say now that this article will be written mainly from the perspective of the services my company provides and the things I have been asked about in relation to these services (obviously). However, a lot of the things I will cover will be reasonably generic to laser scanning in general to the best of my knowledge.
Firstly it is important to understand how laser scanning works, so if you are completely new to 3D Laser Scanning or trying to find out what all the hype is about, it is probably worth having a read of my other article, 10 Most Asked Questions About 3D Laser Scanning at some point.
One of the things I have heard many times in my hundreds of conversations with clients, both existing and potential, is “we have used 3D scanning in the past and we had too many issues with it, so we are not really interested in using it again.” There is usually a number of reasons for this and I will try and cover most of them as best I can.
One of the more common complaints I hear is that the files that were received were not of the right format for the client to use. One of two things normally happens here, either the client doesn’t use the data at all or there are considerable delays getting the files in a format that work. Either way it can be a costly exercise in both time and money wasted. While this is an understandable issue given the current software race to use 3D scan data and the amount of different file formats out there, there are 2 ways to avoid being left with an expensive large file that you can’t use.
1) Before you take on a job that requires scan data, make sure you know for sure the software and hardware you have can work with scan data without any additional upgrades or addons and what file format it works best with. This can usually be taken care of by calling your software re-seller or a quick google search along the lines of “<software name> + point cloud”. Some software requires specific hardware settings or functionality to display point clouds. So just because your program is running fine on your computer, don’t assume it will work with point clouds. Check for the software’s recommended or minimum requirements for working with point clouds and make sure your hardware is up to the task. (including drivers for your hardware.)
2) Ask your scan service provider if they have supplied scan data for clients working with your software and if they know what format you need to use. In fairness there is a better than reasonable chance they may not have supplied data for your specific software, so don’t crucify them for not knowing, but they should be willing to find out or help work it out. If they palm you off with a comment along the lines of “we always give out <insert file format here> and it normally works” then question strongly if this is someone you are willing to work with. At the very least try and get a sample data set to try out.
While these seem like obvious steps to take, it would be easy to get caught out by not using the most current software versions or by not understanding fully what the different file formats mean. File formats in itself are a pretty hefty topic, and if I am honest, one that I am probably only 95% across myself due to the complex nature of the subject. I will try to cover this in more detail as best I can in an upcoming article though.
The next major complaint is “the file sizes were too big and unmanageable”. Again this is an understandable issue given the density of the data collected by the newest iteration of high definition laser scanners, but it is easily avoided if you and/or your service provider understand what you are doing with the files. While it would be easy to spend days optimizing a point cloud for the best balance of performance and detail, there are a few quick steps that any decent service provider should be doing in order to deliver something you can work with.
1) Cloud Clean up. This is a process of clearing out any excess data that is not needed for your job. Talk to your provider about the job you are doing and the detail you need to see in your final point cloud. If the scans are being done outside and there are lots of trees/gardens that you don’t need to see in final scan data, they can be removed and that alone will make a massive difference to the file size. If scans have been done inside a building and the scanner has picked up data through closed windows/doors, the data from outside should not be included in the final point cloud. It can’t be trusted anyway as the laser beam has gone through glass/plastic twice and the information could be magnitudes of error out as a result. If the scans were done in a busy area where there is lots of traffic, mechanical or human, there is likely to be a lot of “noise” in the scan data. That is where something has passed through the scanners beam during the scan and the data that was captured was not needed or incorrect. While this could be too time consuming to worry about removing in some cases, it can make a huge difference to the file size if the scans were done in a very public place like a shopping mall or beside a busy road. Finally, take out all the data other than what you specifically need to work with. While I know that it can be useful to have the neighbors building and what the rest of the street looks like, if you don’t need it, get rid of it. All of these processes can be done in a matter of minutes to an hour or two on most small to medium jobs and should be included as part of the service provided. On larger jobs, point cloud processing should be quoted as part of the final price, and may be a reason that one service provider is a little more expensive than another. You should be asking what clean up service is included in the quoted price if in doubt. Alternately you can edit the cloud yourself, after it has been delivered, with programs like Autodesk Recap and save them to smaller files, but why should you have to?
2) Point Cloud Decimation. This is a process typically done by point cloud registration software where by it will try and remove points from the cloud based on a specific spacing or percentage of points. This process can be quite detrimental to the finished product if done incorrectly and should be done by someone who knows how it works, or should be at least practiced on a copy of the data set until you get the hang of it. Some programs can/will do this as part of the import process, if in doubt; make sure to ask your service provider for some guidance on what settings to use based on the files provided to you. If required, get the non-decimated point cloud from your provider and decimate it as needed on import into your software.
3) Software settings. Most software that uses point cloud data these days, works by only showing a limited number of points at any given time. Typically this number will decrease when zooming or rotating the model, and fill back in when left to sit for a few seconds. This allows the software to strike the best balance between hardware use/speed and detail shown. Most software will allow you to change these settings manually, so make sure you do some experimenting to see what works best for your system.
To give an example of what is possible when these things are done correctly, I have personally delivered a point cloud that on registration of the raw data was over 75Gb in size. When cleaned up the result was a point cloud of 25Gb. When decimated to a reasonable resolution for working with, the result was a 2Gb point cloud (I did get it down to 500Mb, but it was boarder line to “diluted” to use). With some software tweaks we ran it all day on a 5 year old laptop without issue and opened it for a 30 minute demonstration on an 8 year old laptop. Most modelling and drafting offices would be using far better computers than this, so there really shouldn’t be any excuse for not getting a file you can work with.
Whatever happens, you should get a copy of both the clean and original files in a format you can work with. It is very easy to accidentally remove details that may be required when cleaning up a point cloud and it can sometimes be difficult to see detail in a heavily decimated point cloud. So if you have a copy of the full data set then you can always open it to check fine detail or make yourself a new point cloud with the detail showing that was removed by mistake. That said, never ask for the “raw” files, most service providers will think you want the files off the scanner, and unless you actually have the software to read and register these files they will be useless to you. In nearly all cases, you won’t be able to use them for anything and they can be huge lots of information needlessly taking up space on your storage devices.
If you are struggling to work with the point clouds for any reason, it is possible to get the point cloud remodeled into traditional 3D solids. Some service providers offer 3D modelling services as the software that they use to do the registration with can do some 3D modelling from the point cloud. Others will have brought some software specifically for remodeling from point clouds. Other service providers will offer “offshore processing”, where they send the information to countries like India to be processed and returned as a 3D model in a format of your choice. All of these have pros and cons, but I would recommend that if you are going to be using your point cloud to generate a 3D model, then you really should be using a service provider that understands what is required to do 3D models and what you are going to be using the model for. Offshore processing may sound like a great idea, but I have heard more horror stories than I have success stories about it. That said you rarely hear good stories about anything these days, so just think carefully about using it and try as best you can to find a reputable provider of the service. Plenty of them will readily contact you on LinkedIn if you even hint you have anything to do with point clouds, so it shouldn’t be hard to get some websites to look at if nothing else.
The last big hurdle for most people into using 3D laser scanning is price. I have heard some horrific stories about the prices getting charged for scanning services. At the end of the day, what someone sets their price at is their business. If they choose to charge $30,000/day then good luck to them getting or staying in business. (for the record, I have heard of this being quoted.) While the buy in for a terrestrial scanner has gotten a lot cheaper over the last 5 years, it is still quite high. The scanner sales guys will be quick to say a scanner is “only” $40-90,000 (still a lot of money sales guys!) to suck you in to their sales pitch. What they don’t tell you initially is that the software and all the accessories that you actually need to finish the job properly is an additional $40-50,000 or more depending on what you want to do with the data. You can drop $80-100,000 on getting into scanning in the blink of an eye. That doesn’t even take into account the 1000’s of hours it takes to learn how to scan and process the data in an accurate and reliable way. So yes, 3D laser scanning services will be expensive. When doing research on what to charge for our services I found that most service providers operate at between $2000 and $5000/day based on an 8 hour day. This seemed to depend on the services they could provide as much as the size of the company. So if you are being quoted what seems like exorbitant prices or prices that seem too good to be true, then find another provider, or at the very least make sure you are getting service that fits the price you are paying. Remember it is only slightly more expensive to do things the cheapest way!
At the end of the day it is important to find a provider that knows as much as possible about how you use your scan data and what is required of them to provide you usable information. Like any other business relationship it is critical that you find someone who is willing to help as much as they can to grow your business and not just bleed you of as much money as they can to grow theirs. You shouldn’t be left feeling like you’re alone or going to be charged more for anything you ask for once you have your scan data.
If you have any questions or comments I am always happy to answer them. Feel free to ask below or get in touch. Also follow our Complete 3D Concepts LinkedIn page to keep up to date with what’s happening.