What is Hybrid Modelling?

Reverse Engineering (RE) complex freeform surfaces along with geometric shapes has always been a challenge to design engineers. At Physical Digital® we are able to overcome these traditional difficulties to deliver fast, accurate and high-quality CAD models by combining traditional CAD modelling techniques with NURBS Modelling. This is known as Hybrid Modelling. 

Gathering precise data from complex free-form surfaces as well as geometric shapes is challenging. You need dedicated software in order to overcome traditional difficulties in merging the data, resulting in faster and more accurate design delivery.


It all starts with metrology

The final design model is only ever as good as the captured data. The more complete and accurate the data is, the more useful the resulting model. At Physical Digital we use the industry-leading GOM ATOS systems to capture the most accurate and high-resolution data required.

These blue light 3D scanning systems work with stereoscopic cameras that capture a projected fringe pattern to generate surface data. Using the GOM software suite to complete the scanning, alignment and inspection process means that traceability is maintained throughout the project.

Automotive part being captured by GOM Metrology systems

What is NURBS surfacing?

NURBS (Non-Uniform Rational Basis Spline) surfacing allows us to create highly accurate and rapid surface data. The process splits the surface according to areas of high contour, then divides these patches into smaller areas to ensure geometric continuity. The NURBS surface precisely follows the contours of the scan data, and for this reason it is essential to start with the highest quality scan data possible.

Using GOM Inspect software it is possible to create simple geometric features using fitting algorithms directly onto the scan data itself and then these features can be imported directly into the CAD package.

Once extended and trimmed with the NURBS surface, the final model is created which can then be imported back into the GOM project and inspected against the initial scan data to ensure the final surface is within tolerance.

Good hybrid modelling requires an in-depth understanding of the relevant metrology techniques and state-of-the-art measurement equipment.

Although an extremely useful design technique, NURBS surfacing is not suitable for every project and our team will always consider the design methods for each project carefully to ensure the best result for our customers.


Hybrid modelling can either be the start of a major reverse engineering project, or it can be needed at a vital stage in an existing project in order to model or test certain aspects of the design. Whatever the reason for needing this type of measurement, you need to be able to rely on the accuracy, speed and traceability of the measurement process.

Using the highly sophisticated GOM 3D Scanning metrology systems and 3D CAD design packages, along with the expertise of our metrologists, in house design team and vast knowledge from multiple industries (including aerospace, automotive and medical), we are able to deliver high accuracy CAD models for your project.  

With a multitude of CAD tools available to us in the Design team at Physical Digital, each project is carefully considered to decipher the best approach and utilising NURBS surfacing for Hybrid modelling is an example of that. We have to consider the downstream application for the object, which would also help to determine the methods and tools used."

Dom WacSenior Design Engineer


To find out how our 3D scanning services carried out by our expert engineers can add value to your business and transform your project call us, email or fill out the contact form.

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