Once the 3D scanning software has generated the scan, it might be acceptable as-is! Simply download it in your filetype of choice and use it as intended.

However, if the scan needs to be modified in any way, Blender is a versatile software tool that can clean up the mesh, the form, and the color all in one application. Blender’s latest version can be downloaded and quickly installed.

Importing a scan into Blender is relatively routine; however, different filetypes are better suited for monochromatic or color scans. For full-color scans, if possible, export the scan as an OBJ file from the scanning software, which will preserve all color detail captured by the scan. Conversely, for monochromatic scans, an STL file is recommended, because it doesn’t store color information and therefore takes up less memory.

Once these files are downloaded to the file explorer, they can be imported into Blender using the “Import” button under the “File” tab.

As mentioned, mesh errors are common in 3D scans, typically because photogrammetry software and 3D scanners can’t represent the underside of objects, such as the sole of someone’s shoe or the base of a planter. That, mainly, as well as other non-manifold features that creep into the 3D scan from scanning artefacts, typically create the need for mesh modification. Non-manifold geometries are parts that can’t be replicated in reality, such as parts without thickness or edges or faces that are disconnected.

Fortunately, Blender has an entire toolset dedicated to mesh modeling, and several schemes for fixing mesh issues, from non-manifold geometry to included or excluded vertices that need to be eliminated or added.

Firstly, to fix all non-manifold geometry at once, the easiest thing to do would be to follow the advice of Redditor emoUberNoob. This includes being in Edit Mode, not having anything selected, and, just under the top menu bar, going to “Select > Select All by Trait > Non-Manifold”. This will highlight all loops of non-manifold edges, so that it is easy to identify where the mesh might be not manifold. If Blender doesn’t automatically select any loops at this point, then congratulations! Your mesh is manifold, and you can skip any steps related to non-manifold mesh fixing.

Once all non-manifold geometries are selected, deselect all but one and press the ‘F’ key to fill the space in the non-manifold area with a new surface (e.g. connecting edges). You can choose the select tool from the top left, so that you’re working with vertices, edges, or faces. Repeating this process for all non-manifold areas on the 3D print will create a manifold mesh, which means that it can be used as a solid model and be 3D printed.

For inclusions or exclusions of one line or one or two points, first you’ll want to switch to the “Modeling” tab at the top (ribbon bar). The mesh tools that appear allow for the manipulation of vertices, lines, or faces depending on tool type and selection, and are very useful for getting rid of pesky out-of-line points. For example, you can extrude regions to make them meet other points if they’re disconnected from the rest of the model, or you can insert faces as needed.

Beware, though, that deleting parts of the mesh will create new non-manifold geometries that will need to be fixed before treating the mesh as a solid object.

Check out this article for a full run-down of mesh editing in Blender.

Once all individual mesh issues are addressed, mesh sculpting can be used to change the form of the 3D scan, almost like an artist manipulates clay.

Blender offers several unique mesh sculpting tools, which can be used to modify a 3D scan in areas where it was shaped incorrectly or where the scan’s intended use-case means it should be re-shaped. These tools can be accessed from the “Sculpting” menu on the ribbon bar.

Some useful sculpting tools for scan-cleaning are as follows:

• Smooth: This tool is the first red-highlighted sculpting tool in the sculpting tool menu (left of the workspace), and can be used to smooth out inclusions in the scan. Be careful not to accidentally remove detail that should be preserved when using this tool! When in doubt, “Ctrl + Z” (the “undo” hotkey) is a good friend.
• Blob: The second-last blue tool pushes vertices outwards, creating a spherical curvature. This can be useful if there are round parts of a scan that haven’t been properly replicated.
• Pinch: This tool (the first in yellow from the sculpting tool menu) is useful for adding detail by highlighting boundaries between two parts of a scan. Did the raised letters on a jacket not show up properly in the scan? Tracing the boundaries of those letters with the “Pinch” tool will create a crease that increases the visibility of small features that are sometimes poorly-separated from nearby objects.
• Simplify: This tool (right beneath the purple “Cloth” feature) is useful for reducing file size, especially because some 3D scanners will go into very high detail in areas where high detail isn’t strictly necessary. Reducing the polygon count in these areas (which in scans of persons is often near the sides of the nose) will increase performance and make it easier to store and e-mail the finished scan.

These sculpting tools are very helpful for addressing inclusions and exclusions made from extraneous activity in 3D scans. If you’re scanning someone using photogrammetry and their head turns during the scan, parts of their face will be left out. These features can be reconstructed relatively faithfully with the blob, clay, and pinch tools to respectively build, even out, and shape the mesh features.

Lastly, it’s important to note that sculpt tools are designed to manipulate several mesh triangles at once, and it can cause sharp features to get lost in the sculpting process. Don’t be afraid to go back and use mesh editing tools to move individual edges and vertices around to preserve sharp corners in the scan. In the image above, the “blob” tool smoothed out the eyes in order to make the blob. This is an example of what could be corrected with the aforementioned mesh editing tools.

For full-color scans, sculpting tools can create unintended color deformations. That, coupled with color artefacts from scanning, means that full-color scans often need to be color-edited. Even more so, monochromatic scans can be colored somewhat easily, should the designer want to add three or four hues for multicolor printing.

It’s not uncommon for photogrammetry software to apply background colors to the scanned object, which can be fixed relatively quickly using Texture Painting. This is a feature for editing the color of a mesh that involves “unwrapping” the mesh so that it is a flat surface, painting on it as if it were a program like MS Paint, and then “rewrapping” that surface back around the object. A good illustration of how to do this is Blender Guru’s Blender Donut tutorial. Texture painting is a rather advanced tool, but it’s very effective at fixing small color issues that might affect a 3D scan.

Additionally, to automatically add color (or even to extract textures from full-color scans), Blender has a feature called UV mapping that can add a pre-built image onto a monochromatic scan, which can be used in reverse to extract the color map of a 3D scan into an image that can be used for other purposes. These can be used when a monochromatic scan of a particular object should have a pattern added to it (perhaps a plaid couch) or in instances where logos should be added. It is functionally the same as putting a Minecraft Skin on a blank Minecraft character from an unwrapped Minecraft character skin image.