Producing Geometry You Can Trust

QC provided an engineer for our project who did a great job of collecting the dimensional data for the parts to be reverse engineered, creating the CAD models, and producing prints for manufacturing. He kept in regular contact with me throughout the project, allowing us to quickly resolve issues as they arose. He was also very responsive when asked to make changes to the prints. Overall, a superior job.

- Paul,
Power Generation

Go back to Archive

From Laser Scan to Surface File

Scanning equipment captures 3D positions of individual points. What is done with the point cloud after the scan depends on how the final geometry will be used.

If you do not need a fully editable (parametric) CAD model, a surface file may be a less expensive output to generate, depending on the part. This method is best suited for artifacts with shapes that are organic in nature and when texture needs to be retained. The file is often referred to as a "dumb" solid or a NURBS-generated surface file.

The first step is to generate a polyginal model of the points. Essentially, every point is connected to its neighboring points, resulting in thousands of polygons that represent the surface of the object that was scanned.

Then software is used to "lay" a surface "mesh" on the object. Some parts require many hours of mesh editing before the final surface can be applied.

The result is a NURBS-generated IGES or STEP surface file that very accurately represents the original scanned part. You can scale this file, cut it, add features to it; but you cannot offset from it or edit individual shapes. That's because the surfaces do not have the same mathematical foundation as a parametric file.

So, in answering the question, "Can you save it out as a CAD file?"... No scanning technology has the ability to "convert" points to CAD data (at least not yet). Some software programs have accelerated the process of developing files, yet none are fully intuitive.

Each step of the surface model build requires a decision to be made about design intent, textures, sharp edges. Hence the need for a skilled engineer to develop a completed model that contains the proper shape, parting lines, and accuracies you'll need for your next step.

At QC, we want to clearly understand your next step so that you'll end up with a file that moves you ahead on your project. We like to think of it as Geometry You Can Trust TM

Read Past Engineering Articles