Scanning/Modeling Jewelry - A Collection of Tips

Background – Scanning/modelling jewelry

We recently had a request around how a developer might best produce 3D models of jewelry so as to display and interact with them as holograms in HoloLens. A number of folks contributed some thoughts and resources that we thought might be generally applicable and so we pulled them together here.

Feedback

This is far from an exhaustive list of resources around how to approach this type of work, so if you have additional comments, please add them to the discussion below so everyone can gain from the shared experience.

Guidance

The first thing to note is that it may be worth contacting the jewelry manufacturer, as they may have 3D models of their products which could save you a lot of time.

If that’s not an option, then you can find some solid 3D modelling talent or consider the following options to ease your work…

Scanning/Photogrammetry

You can try photogrammetry, but be aware that accurate scans take lots of time, patience, and a high-quality camera. This technique isn’t suitable for items much smaller than a watch.

Here are some great “getting started” links:

• PhotoScan and Photogrammetry Overview
• Environment Scanning Overview
• Agisoft PhotoScan Software (for photogrammetry): Good software for indies that can produce high-quality results. There are other packages but they generally involve a subscription and might cost more. Take a look at Agisoft , and here’s a great tutorial around how this might be used

In addition to Agisoft, also take a look at Capturing Reality for DSLR photogrammetry, and Wrap for mesh/scan wrapping.

It’s also worth looking into 3D scanners like the Matter and Form scanner. They might help automate the scanning process for small objects like jewelry.

The biggest problem with either technique (photogrammetry or scanning) is that transparent surfaces can show up as holes, and glossy materials or pure white/black can be problematic. The scanning and photogrammetry processes look for color variations and lighting as the object rotates (or as the camera rotates around the object) to infer the shape of the object, so diamonds might not show up as solid objects. This might lead to modelling the pieces by hand.

To counteract this, try using a powder or tape on larger surfaces with a color/material that allows for shading or some type of (removable) dulling spray.

Photogrammetry may work well on the gems, but the downside will be the reflections. You might have to splice out the gems and assign a new material to them with your shader. Then you’ll need to replace the material with a metal shader since you’ll have different lighting interactions between your gem and your purely image-based, non-physically-based material capture. Ideally you want physically based materials across the board for realism, so simple textures from photogrammetry won’t work.

Blue lights scanners have been pretty successful in eliminating noise, but again, transparency may be the down side. They should work well for opaque jewelry.

It might also be possible to get scanning done for you if you ship jewelry to a scanner (as an example) purchase your own like Artec Spider, or contact a scanning vendor.

For items much smaller than a watch, you’re probably best with traditional modelling.

Shaders

Shaders are hard to learn. If you don’t want to become a shader expert, take a look at Shader Forge which gives you a drag-and-drop UI for creating shaders. You might want to try out the course on UDemy.

Reducing polygon counts

Scanning is notorious for creating noisy high poly meshes. These types of meshes present a challenge because they don’t render quickly. You can use Simplygon to clean up these meshes before using them in a HoloLens app – here’s a [video specific to HoloLens] (https://www.simplygon.com/news/optimization-cad-asset-for-hololens), and this works as a standalone app as well as a Unity plugin. They have a free version for testing and non-commercial use.

We hope these resources help! Jewelry is just one example of complex objects that these tools scan and model. Let us know other objects you’re tackling and share your tips in the comments!