3D Scanning Shiny and Transparent Objects
Exploring the limitations of structured light scanners and how to work around them when scanning subjects with more challenging textures
As we've mentioned in previous articles, some textures, such as shiny or transparent ones, don't always play well with 3D scanners! A structured light scanner (the kind we employ in our studio) works by projecting a grid pattern of light onto its scanning subject. Cameras on the scanner watch the pattern of light and determine things like size, shape, and surface details of the subject by observing how the grid lays over the object. This process provides amazing and accurate detail for subjects with 'standard' (i.e. opaque, non-reflective) surfaces. Enter shiny and clear objects and things begin to get a little more complicated.
As shown in the illustration above, clear and transparent surfaces allow the scanner's light grid to pass through them, preventing the scanner's camera's from being able to observe how the grid lays over them. On the other hand, shiny objects cause the opposite problem. The light grid is reflected off of the subject in a way that obscures the grid and the scanner is once again unable to observe the surface of its subject.
Common examples of shiny objects could be reflective plastic, mirrors, and smooth metal components. Examples of clear and translucent objects could be glassware, wax, and gemstones. While these surfaces can cause issues for a wide variety of 3D scanners, there are a few things we can do to work around them. Namely, applying sprays and powders to the scanning subject to either reduce its reflectiveness or increase its opacity. It's important to note that some of these treatments are temporary and can be easily removed from the scanning subject, whereas others are permanent and unable to be removed. It is also important to note that sprays used to bring opacity to clear subjects will prevent the scanner's ability to capture the subject's color. However, it is possible to apply a handmade color texture to the 3D model later, as we discuss in our blog posts Editing Materials on 3D Scans and Custom Textures with Quixel Mixer.
The following is a list of sprays and powders that can be used for scanning:
Talcum powder (removable): Shiny and reflective objects can be lightly dusted with talcum powder to dull shine. The coating of talc required is light enough that it will not interfere with the scanner's ability to capture the subject's color in any noticeable way. Talc powder can be wiped away from the subject once scanning is complete.
Scanning Spray (removable): Transparent, opaque, and particularly reflective objects can be sprayed with a specially formulated scanning spray that will temporarily cover the subject in a light, even coating. The spray our studio uses cleanly evaporates from the subject within a few hours and leaves no residue. Because the spray is opaque it is important to note that it will prevent the scanner from capturing the subject's color.
Matte Finish Spray (permanent): Matte finishing sprays, such as Krylon Matte Finish, can help dull shiny objects with an even matte finish. The spray will not interfere with the scanner's ability to capture the subject's color at all, but it is permanent and cannot be removed from the subject once applied.
Please note that it's likely all transparent and translucent items will need some kind of spray coating to scan well. However, not all items with shiny surfaces will require spray or powder, depending on how reflective they are. Curious if your shiny or clear object will scan well? Send us an email with a photo of your item and our team will be happy to let you know if it needs any powder or spray!
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