Scanning the object

Figure A

Figure B

Figure C

Figure D

Figure E

Figure F

Figure G

Figure H

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.

SAVE YOUR PROJECT WHEN YOU'RE DONE SCANNING!

How To: Artec 3D Scanners