3d Scanning can be done in multiple ways and at multiple price points, either with handheld scanner for an iPad all the way up to full systems, e.g for car manufactures to scan clay cars.

They also have different degrees of accuracy, with hand held scanners being less expensive they will also produce less detailed scans, but still very much usable.

Photos to wire frame to surfaces

This is the process of taking a few images and importing them into a CAD software such as Rhino and creating a line drawing from the outside of the image and then building up a CAD model from that. This will produce a very accurate CAD model with clean surfaces, however it might be harder to get in the fine details for the thing you were taking photos of. You may also struggle if the object is very complex or if it has lots of small details on one face, making it difficult to get side profiles of these features.

The main steps are:

1. Use a curve tool for draw the rough shape
2. Clean these up with either rebuild curve or by dragging points on the curve
3. Add in additional details such as the mouse wheel
4. Use this wire frame to create surfaces which can be then used to 3D print

Photogrammetry

This is the process of taking lots of photos and importing them into a CAD software creating a 3D image using relative distances between the photos. This can normally done with an app as well as a corresponding desktop application as it can be quite intensive to create the model from the photos depending on its complexity.

3D scanning

3D scanning was done using scanners which attached to an iPad, making them very convenient to use; https://structure.io/

The scanning process is relatively simple as the app tells you what to do at each stage

1. Launch the app and locate the box on the screen on the object that you wish to scan
2. Change the size of the box to suit that of the object
3. Click start and slowly move around the object ensuring that all angles are covered. It will tell you from time to time to stop and wait while it picks up all of the surface details.
4.  Send this via email from the app to start the next process

At this stage you can either use this scan to create a wire frame in a program such as Rhino and create the surfaces as above, or import it into a mesh altering software such as Meshmixer.

Rebuilding

As in the photo to wire frame method, the aim of this is to create a wire frame from the 3D model and then create new surfaces, which will overall give you a much better surface finish, but will be impossible to do on something organic such as an arm.

The 3D scan is brought in and rectangular surfaces are put in to create the main wire frames. Project to surface command is then used to obtain the exact curves. These can then be cleaned up or redrawn as above and then surfaces created using on to the multiple surface tools. This is the the most time consuming method but produces the best results and the highest quality surfaces.

Meshmixer

Meshmixer is a free software which allows you to create and edit meshes and 3D objects, such as 3D scans.

1. Import you wire and use the simplest tools to reduce your work.
2. Use the simplest commands first such as ‘Close Gaps’ – this  command will almost always turn a lot of work into very little.
3. The next best thing is to try and make the object a solid. I found it best to cap the base of the hand and set it at the desired angle. Use the Translate tool for this.
4. Capping the base of the hand is done using the ‘Plane Cut’ tool. This acts as a knife and cuts a flat surface through your object.
5. Use the tool ‘Make Solid’ to convert your shape into a solid. It isn’t perfect and left the space under my fingers a mess, mostly due to the lack of light when scanning and therefore details couldn’t be determined.
6. Using the Sculpting tools the errors made by the scanner such as mussing out under the fingers can be corrected.
7. This video shows the entire process of sculpting and editing the scan

Files – Before and After

3D printing

1. Load the document into Ultimaker Cura which allows you to preview and edit the 3D printing details
2. Once loaded, orientate the model into the desired place and ensure that it has imported in at the correct size. It is important to think about the orientation due to the layers as any overhangs which may require supports. Reducing the number of supports will reduce the print time as well as decrease the need for cleaning up after printing.
3. Click Slice in the bottom right, then preview when this is completed.
4. Under print settings you can choose the layer height – main time saver along with infill % – This will require the slice command to be run again
5.  Preview of the layers being built up; showing the support material

Fist .stl file

Final Image