Everything You Need To Know About Decimating 3D Scan Data [With Video Demo]

Decimating 3D scan data simply means you are making your file size smaller by reducing the number of polygons in your 3D mesh.

A 3D scan mesh can output into an enormous file size (sometimes up to 1 GB!) during the 3D scanning process. Doing this extra step helps reduce the amount of excess and redundancy that is not needed.

For best performance and efficiency, reduce the number of polygons by decimating the data. If done properly, you can maintain relatively good accuracy and resolution compared to the original file, without compromising on quality.

Why Decimating 3D Mesh Helps With Optimization

You are managing the file size for faster processing. The goal is to reduce polygon count without sacrificing on the detail. When using the scan file for downstream applications, decimating your scan file can help you work faster and easier.

For example:

It’s easier to upload to websites like Sketchfab since a smaller file size means a faster upload. In addition, your account usually has a limit to the file size limit per upload. In the Sketchfab Pro account, there is a restriction of 200 MB file size limit per upload.
Your 3D printer might not need that high of a resolution for printing. Having a smaller file size means less processing time and it makes it less complicated for the 3D printer to print your object. You are also less likely to get errors during the printing process.
For reverse engineering, your computer might not be great at dealing with a large file, especially if you have an older computer. This can lead to lags and freezing to cause a lot of troubles when trying to get work done. Decimating your data will help the performance of your computer.

In addition, as 3D scanners are becoming more affordable and accessible, a vast amount of 3D data files get accumulated in your organization. Decimating your 3D scan data is one way to handle data management.

How Do You Decimate 3D Scan Data?

Here are two video demonstrations of decimating your 3D meshes inside Geomagic Wrap.

Mechanical Part

Organic Object

Side-by-Side Comparison of Before and After

Raw 3D mesh is comprised of millions of polygons. You don’t need all the polygons for areas of low curvature (usually flat surfaces) to maintain the structural integrity of the 3D model.

Comparison #1

whole sprocket 3d scan — **Before decimation:** ~ 1,000,000 polygons
**File Size:** 50 MB (Saving this as a binary STL in Geomagic Wrap)

whole sprocket 3d scan decimated by 50% — **After decimation:** ~500,000 polygons
**File Size:** 25 MB (Saving this as a binary STL in Geomagic Wrap)

whole sprocket 3d scan decimated by 90% — **Further decimation:** ~100,000 polygons
**File Size:** 5 MB (Saving this as a binary STL in Geomagic Wrap)

Comparison #2

before decimation — **Before decimation:** ~ 1,000,000 polygons

decimated 50% — **After decimation:** ~500,000 polygons

decimated 90% — **Further decimation:** ~100,000 polygons

Comparison #3

high resolution original scan zoomed in — **Before decimation:** ~ 1,000,000 polygons

Takeaway

As you can see, decimation is similar to why you want to compress a file on your computer in order to save space in order to remove unnecessary and excessive weight. However, with decimating 3D scan data you have more control as to where and how you want to do it—all the while keeping the structural integrity of the 3D mesh (shape and detail) intact.