Mesh Registration and Alignment

It’s the summer holidays soon. Yay. But after that things start to get a little busy. Our trade show season starts– we’re exhibiting Polygonica at EMO in Hannover and Formnext in Frankfurt.

But more importantly, Polygonica 3.3 will be released in the autumn – and that always generates lots of questions from both existing partners and interested observers keen to see how Polygonica can help them meet their goals.

Although there is an official major release of Polygonica once a year, there are also patch update releases, usually between eight to twelve per year. These include fixes to bugs reported by customers, but now also include new functionality - where it can be added without significantly changing existing areas of the code.

This blog is the first of three quick catchups on some of the new functions developed for Polygonica 3.3, but already available through patch updates to the 3.2 release.

“You like potato and I like potahto
You like tomato and I like tomahto
Potato, potahto, Tomato, tomahto.
Let's call the whole thing off”

It’s a great song, but I’ve never met anyone who says “potahto”. But then I’ve never met Dan Quayle either. But I did meet someone who looked blank when I said “registration”, but when explained further they told me ‘ah, you mean alignment’.

It’s possible there are subtle differences, but we’ll use both synonymously. This is Sales and Marketing after all.

In Polygonica, registration is the process of aligning two similar, but differently positioned and oriented objects, so that they match as closely as possible and the distances between matching points on their surfaces.

Registration is useful in a wide variety of workflows – typically any time you are working with geometry data captured from the real world such as laser, optical or CT scanning.

Examples include:

• Accurate modelling of medical and dental implants including crowns, aligners,
• Automated quality control on production lines
• In-process monitoring of metal additive manufacturing, including deformation computation and distortion correction.
• Reconditioning of worn cutting tools, turbine and impellor blades etc, using multi-axis robotic additive methods.

Mesh-mesh registration was added in Polygonica 3.2. In the 3.2 Patch 3 release the new API was updated so the data to be registered could be a point cloud or a point set.

This was added specifically to speed on machine verification for both additive metal printing and CNC subtractive machining. :

You can see a demonstration of point cloud to mesh alignment on Polygonica's youtube page:

A nice feature of Polygonica’s registration is that the client can specify a region of interest to be prioritized, such that the distances between the two objects will be minimized in this region in priority to other regions in the mesh.