Plug in the Artec so that it can warm up.

Before you start scanning, you should have a mental picture of how many scans it will take to cover the object, as well as the ways in which you will place the object for each of the scans. Remember that you want some overlap between each of the scans. Ideally one scan would encompass or overlap with several other scans. Remember which scan has the most coverage (it may not be your first scan), because this scan will be the scan that you use first if manual alignment is necessary.

• If you are scanning on the turntable, make sure that you can spin the turntable completely without the object bumping up against the monitor.
• Make sure the scanner's power and USB cables are clear of any obstruction and plugged in.
  • If the scanner is plugged in via USB and is turned on but not showing up (fig. A), restart Artec Studio.
• Although Artec Studio will usually detect the scanner, make sure that your settings are set to the correct scanner (fig. B). This is extremely important if you are using two scanners to scan the same object.
• Under the scan menu in fig. C, these are the settings I've most often found myself needing to adjust.
  1. This can be a time-saving step, but when scanning cultural heritage objects I've found it best to just disable this feature. I like to ensure that I am in control of what I'm deleting, but I also often use sandbags to stabilize or otherwise prop up the object, so the automatic base removal tool doesn't end up saving any time. Better safe than sorry, and it's one of the easiest parts of post-processing anyway.
  2. Scanning speed refers to the frames per second with which the scanner 'scans' the object. Artecs are structured light scanners, which basically means there are multiple cameras (3 for the Eva, 5 for the Space Spider) at fixed angles taking simultaneous pictures of an object. I have rarely, if ever, adjusted this for my Space Spider. However, I've found that 16fps with the Eva is quite fast, and if you're scanning a large object like a sarcophagus, this can very quickly make your project size difficult to manage. Fewer frames per second means fewer images, which does technically mean less coverage but also means a smaller project size. Less can be more, so make adjustments as necessary. If you find your computer chugging when working at the Space Spider's maximum 8fps, consider upgrading your memory. Otherwise, lower the fps and scan the object more slowly and methodically. 
  3. Most of the frames that Artec scanners capture are B&W. Every 10th or so frame is a color image, and its these images that Artec uses to add texture to your fusion models. However, you'll notice as you're scanning that the real-time object that you're seeing is in color. Similarly, the scans themselves are also in color. This particular brightness setting adjusts the brightness of the scanner as it scans and is unrelated to the option to adjust the texture's brightness after you've applied texture. If you're dealing with an object that is inherently bright/light (like white or off-white), try adjusting the brightness. This can be done on the fly, so press once on the scanner to activate, and then point at your object and adjust the texture brightness until the object shows up most clearly in the preview.
  4. I have experimented with disabling the flash while using a single, bright LED panel placed directly over the object. I have also experimented with the same LED panel setup with the flash bulb enabled, and have have not noticed a difference. Still, this option is important to know about because if you're working in a museum setting, curators may be nervous about the bright strobe light that the scanner emits, and it's good to know how to turn it off. The scan very well may not work, but if you find yourself at a location where they want to try a scan of an object but don't want the flash, it never hurts to try. I would caution against organizing an entire scanning trip that is planning on disabling the flash for all or most of the scans, however.

If you are doing a scan at your desk using the Space Spider, for example, I recommend using a turntable if possible, along with a "noisy" background. See figures E and F in the next section, along with an explanation of why this matters.

Both the Eva and the Space Spider have a working distance, as well as two linear fields of view: the closest and the furthest range, respectively. Working distance refers to how far the scanner has to be from an object for it to work, and the linear field of view refers to the size of the "window" that the scanners can see (fig. A). In case you're curious, the measurements of both are in figure B. As you can see, the Eva boasts much larger fields of view as well as a larger working distance. This is because the Eva is designed for human-sized objects, whereas the Space Spider is intended for smaller objects.

It is theoretically possible to use the Space Spider to scan any sized object, even an entire building, but the limiting factor here is your computer. Scans will be stored in your computer's memory, so the more RAM you have the greater the feasibility of scanning larger objects with the Space Spider. However, computing muscle notwithstanding, it will take you much longer to scan a sarcophagus with a Space Spider than it will with an Eva. And the resulting model will be monstrous (one scan of a sarcophagus using the Eva produced a model with nearly 40,000,000 polygons). Depending on where your model is going to end up, you may end up having to simplify the model (reduce its polygon count) to even be able to upload it. And also consider that although your computer may have the hardware to handle tens of millions of polygons, the folks that you're sharing your work with may not. 

You'll want to strike a balance between preservation-level quality and accessibility. For example, if you're scanning a large object that has fine details, such as carvings or decorations, consider scanning the object in its entirety with the Eva and then using the Space Spider to cover areas that you want to capture in greater detail. This should be done in the same project, but you'll need to make sure that your scanner settings are changed in between the Eva scans and the Space Spider scans. It is possible to do these two scans separately and then merge the projects later on, but this is a lot more work, so it's advisable to be extra cognizant of your workflow and using both scanners in a single project. (Each time I've done this, I've explained to those around me what I'm planning to do, and have asked them to remind me to change the settings in between each scanner.)

The actual scanning process itself will be relatively quick. When scanning, your attention should be on your computer screen and Artec Studio, not on the object itself. You'll acquire a feel for each scanners' working distance over time, but most of your attention will still be on your computer screen. This is because you should be monitoring what the scanner is seeing just as much as you should be monitoring your distance from the object. In doing so, you can quickly spot trouble areas that the scanner isn't seeing and make angle adjustments on the fly. To begin, press the top button once on the Eva or flip the switch up once on the Space Spider. This will enable the preview mode. In figure C, the column left of the scanning area represents the working distance of the scanner. The green boxes are where you want to be, with the optimal distance being the center box. Once you've got a feel for your spacing, press up (or flip up) one more time to activate the scan. An active scan is distinguished from the preview mode by the green tint and outline in the scanning area (fig. D). Areas that are outlined in green are the areas that are being scanned/captured. To end a scan, press down or flip down.

When scanning, do not be afraid of moving the scanner. In fact, I would encourage you to tilt your wrist and rotate your hand to point the scanner in different directions and angles. As long as the object doesn't move relative to the background/environment, you should be OK. This isn't to say you won't lose tracking, but rather that moving the scanner around isn't causing the loss of tracking (unless you're moving it outside of the working distance, of course). For example, in figure E, the object being scanned is on a turntable. So although the object is being rotated on the turntable, the background/environment is also being rotated in the same manner as the object (fig. F).

My workspace in figures E and F may seem bizarre, but it's all designed to help the scanner maintain tracking. Maintaining tracking just means that the software is able to continuously construct a three-dimensional model from what the scanner is showing. So if you're scanning a blue object with a blue background, the software will likely lose tracking and be unable to generate a 3D model. That is why the turntable has printed and scribbled gibberish on it, to help distinguish the brown wood from the brown object being scanned. This particular object is rather small, so I placed it on a raised box (with red and yellow coloring to distinguish it) so that I could more easily capture the object from ground level.

Loss of tracking can happen sometimes during the scan, and is reflected by loud beeps and the scanning area turning red (fig. G). This can also happen if you move out of the working area (too close or too far from the object), but the result is the same. The software will try to regain tracking by finding its place again (fig. H), but in my experience it's best to cut your losses and end the scan by pressing the bottom button on the Eva, or flipping the switch down on the Space Spider. Oftentimes even though Artec Studio says it has regained tracking, your scan will have errors (duplicate parts of the object), so instead of wasting time with the scan it's best to just stop and start again.

Once you're done with your scans, you can begin processing them into a 3D model. If you're working with multiple objects and are pressed for time, it's a good idea to leave the processing for later when you're back in the office. Of course, you'll need to keep in mind that if you won't get access to the objects again, you'll need to be extra careful about ensuring you have full coverage of the object. Here is the basic outline of the steps in the process (fig. A):

1. Fine registration (usually done automatically after exiting scanning mode).
2. Editor - base and excess scan data removal
3. Alignment - auto alignment if possible
4. Global registration - possibly followed by deleting frames
5. Outlier removal
6. Fusion - sharp fusion most likely
7. Fix holes - or go back and re-scan portions of your object
8. Texture application - unless output is just an STL file

Perhaps the steepest learning curve in this whole process is becoming proficient in rotating and manipulating 3D objects. Controls are consistent across tools, so here they are:

• LMB: Click and hold to rotate object around center axis.
  • Double LMB - reset the center axis (signified by red dot)
• RMB: Click and hold, moving up or down, left or right to zoom in or out. (this can also be done with just scrolling, but the mousewheel method is much more imprecise than using RMB).
• Mousewheel: click and hold to move object laterally up and down or left and right.
• Ctrl + LMB: brings up selected tool, click and hold to select region.
• Ctrl + scroll: changes selected tool size
• Ctrl + Shift + Scroll: adjusts plane level (cutoff-plane selection tool)
• Shift + LMB: move only unregistered scan (Alignment step)

Within the Editor window you'll find the Eraser tool, which is what I mainly use. Most of the other tools won't be used, especially if you're scanning cultural heritage objects for preservation purposes! If you've disabled the base removal tool, the first step will be to remove the base. To do this, select the Cutoff-plane selection tool. You'll want to orient the part such that the base is parallel to the ground (fig. A). To do this, use the LMB to rotate the object until it is in the correct position. Alternatively, you can use the Positioning tool (also in the Editor window) to re-orient the object to make it easier. (I recommend becoming proficient with using LMB, as this skill will help you during manual alignment.) 

• To use the Positioning tool, simply click on three points that are roughly on the same plane and hit apply (fig. B). Note that the base can now be made parallel to the ground using the orientation tool in the upper right corner of the screen.

Once the base is roughly parallel with the ground, use the cutoff-plane selection tool to highlight the base. You can be pretty imprecise, as in figure D, so don't worry too much about accuracy or even the size of your selection. Next, use the LMB to get a top-down view of the scanning area so you can see what parts of the base are going to be deleted (fig. E1). If necessary, use CTRL+Shift+Scroll to move the plane up and down while in this top-down view. In this case (fig. E2), one scroll up was sufficient to cover enough of the base. You can always change your view to make sure that you're not deleting too much of the object while using this tool. In this example, it doesn't look like it will be necessary to use the 2D selection tool (or any other Eraser tool) to delete excess scan data.

However, if you're using sandbags, for example, this will definitely be necessary. Figure F shows an artifact that is being propped up by white sandbags. In this situation, the base removal process will not delete everything that needs to be deleted. For cases like this, the 2D selection tool is useful. By now you may have noticed that while working with the eraser tool, the texture of the scan is removed, leaving a metallic color in its place. The color is arbitrary and is randomly chosen. You can change the color of each scan at any time by clicking on the colored square to the left of each scan in your Workspace window (fig. G). Outside of the editor tools, you can show the scan color from the view menu (fig. G). You can also change the object from solid, to wireframe, or to a point cloud (fig. G). This last part is important, because if you switch to the point cloud view while using the eraser tool, it can become much, much easier to see the division between the object and the sand bags. Additionally, changing the scan color to something dark can, in turn, make the point cloud even more visible. This is illustrated in Figure H: the first image shows the same model as in figures F and G rendered as a solid, the second image is the same as the first one except it's rendered as a point cloud, and the third image shows the same point cloud but has the scan color changed to something much darker than the original yellow. The difference may not be very striking at first, but the difference becomes more obvious as you rotate the model around using LMB. In addition to these tricks, it also helps to look at the original scan color outside of the Editor tool in case you're not confident if what you're looking at is sandbag or object. Ideally you'll be using sandbags that are a different color than your object!

Once you've isolated the sandbags (don't be afraid to zoom in using the RMB for more precision), simply use the 2D selection tool to highlight the sandbag and delete it. Don't forget that you can increase the size of your selection tool with LMB+scroll. Once the sandbags and base have been deleted from each of your individual scans, you can move on to the alignment phase. Don't worry too much about getting every little bit of noise deleted; this can be done later on in the outlier removal phase.

Just like in photoshop, you can enable or disable different layers, or in the case of Artec Studio, scans. It's the same little eye icon in your workspace window to the right (fig. A). Before you hit the Align button, make sure that all of the scans that you want to align are enabled. Once they're all enabled, hit the Align button and then click on Auto-alignment (fig. B). If all of your scans auto-align, you're all done! Move on to the next step, global registration. If auto alignment doesn't work, it'll be pretty obvious to the human eye. If the object is too symmetrical and you're unsure if the auto-alignment has worked, try switching to the scan color to see if the surface geometry looks aligned. If you're still unsure, you can either work through manual alignment or complete the rest of the process and compare the finished model with the original object.

In the event that auto alignment just doesn't work, you can do it manually. Recall earlier that I said that you should plan to have at least one scan that has overlap with at least two other scans. This is the part of the process where that can really help. In figure B you'll notice that our two scans are now on the left. One is bold with a blueish circle next to it, the other is regular font with a green circle next to it. The same color scheme can be see in the picture-in-picture screenshot. The bold/blue scan is called "registered" where as the green scan(s) are unregistered. You'll want to set the scan with the most coverage, or the scan that overlaps with two or more other scans, as your registered scan. To do this, simply right click on the scans to change them from registered to unregistered and vice-versa. In our example we are only aligning two scans, but if we were working with more than two, you could have multiple unregistered scans. Registered scans are always visible, unregistered scans only become visible when they are selected. Although you can select more than one unregistered scan at a time, more often than not you'll only want to work with one unregistered scan at a time.

Once you have your registered scan in place, select one unregistered scan. Hold down the Shift key and use the mouse button as you would normally to rotate/move an object. Notice that the unregistered scan is the only one that moves. If you don't hold down shift, you'll move all of the scans, both unregistered and registered, with your mouse. Position the unregistered scan so that it is next to the registered one, with the overlapping portions of each scan visible to you. Recall that you can change the axis of rotation by double clicking. In figure C, I've got both my scans aligned in such a way as to show the overlapping area. Sometimes it can be difficult to tell, so it can be helpful to toggle between the scan color and the texture to highlight both the color of the object as well as its surface geometry.  In this case, there's a dark patch that is a good indicator, and the surface geometry reveals carvings that appear to be the same as well. The more practice you get with manual alignment the better you'll get at planning your scans ahead of time.

Now that the scans are oriented in this way, we can begin to tell Artec Studio where to align the scans. To do this, simply alternate clicking on one scan and then the other, with two successive clicks indicating the two spots on the two scans that should be aligned. You can toggle between the texture and the scan color, as I mentioned, to help you find matching points, as in figure D. Once you've got your points (minimum three sets, in my experience), click on the Align Markers button. Rotate the scans to make sure it looks good, and then either click on the Align button or right click on the unregistered scan you're working with and mark it as registered. Continue on until all your scans are aligned and hit the apply button. You're now ready for the next step: Global Registration.

For more details on what exactly global registration does, consult the Artec Studio manual. Suffice to say that global registration takes each individual scan, no aligned, and turns it into a single point cloud behind the scenes. I say "behind the scenes" because there won't be any one scan added to your workspace. Instead, what you'll see is the Max Error of some or all of your scans change. Ideally, this step makes the max error go down. The ideal for the Eva is around 0.3-0.5, the ideal for the Space Spider is 0.1.