What Is Mesh Decimation and Why Is It Vital for AR?

Why Is Mesh Decimation Critical for 3D and Augmented Reality Applications?

Mesh decimation is a method of 3D model optimization that simplifies images in order to shrink file size to improve load speed and meet the requirements of various platforms where the 3D models are published such as Facebook, Instagram, and Shopify. This plays a crucial role in making 3D and augmented reality images user-friendly for effective deployment in ecommerce applications. Let’s take a closer look at what mesh decimation does, why it’s important and how it can be optimized by using the right technology.

What Is Mesh Decimation and What Does It Do?

Mesh decimation is a technique for managing the details in 3D model representations by simplifying the underlying shapes. This is done by reducing the number of vertices, edges or faces which make up the surfaces of the polygons that form the building blocks of the 3D model. This is done without substantially altering the visible shape, volume, and boundaries of the 3D model.


To better understand this explanation, let’s break down what we mean by a mesh and what’s involved in decimating a mesh. A 3D model uses software to represent a physical object by mapping its shape and other properties onto a three-dimensional coordinate system. The object’s shape is represented by a collection of points called vertices. Vertices connect to form lines known as edges. A closed set of three or more edges connect to form the faces on the flat surfaces which make up polygon-shaped 3D objects. For example, three closed edges can form a triangle face, and a pair of triangle faces can form a rectangular polygon on the surface of a box-shaped object.

Theoretically, faces may have three, four or more edges, creating polygons with any number of sides of three or more. However, in practice, most hardware used for 3D rendering only supports faces with three or four sides, with three being easier to manage, so triangles most commonly are used for 3D modeling.

When this method is used to map a physical object onto a collection of points forming triangles or other shapes, the resulting coordinate system looks as if the object had been wrapped in a net made of wires. The model defined by this coordinate system is known as a wireframe model, and the net-like collection of points and shapes which makes up the model is called a polygon mesh. When a polygon mesh is made up of triangles, it is called a triangle mesh.

Mesh Decimation

To decimate something literally means to reduce it by one-tenth, as in a battle where one army destroys a tenth of another. In a 3D modeling context, mesh decimation involves simplifying the level of detail (LOD) on the shapes underlying a mesh without substantially altering the visible appearance of the 3D image.

This is done by using a set of computer programming instructions to reduce the number of vertices, edges, or faces on the shapes which make up the image. The set of programming instructions used to simplify the image is known as a mesh decimation algorithm or LOD-ing algorithm. A 3D object which has been simplified through mesh decimation is said to have been LOD-ed.

A mesh decimation algorithm reviews the vertices which form a local area of a mesh and removes vertices, edges or faces which are not necessary to maintain the general contours of the area. For example, edges may be collapsed by combining a pair of vertices into one vertex.

Mesh areas are removed based on criteria set by the algorithm. When an area is removed, it leaves a hole in the mesh. The algorithm then patches the hole by forming a new local triangle or another polygon. This process continues until a terminating condition defined by the algorithm is met. Usually, this terminating condition is defined in terms of a percentage of face reduction. For example, an algorithm may be set to yield 75% reduction in the number of triangles composing a model.

The process of mesh decimation can be done without substantially altering the visible appearance of a 3D model as it looks to the human eye. This is because most models initially contain more complexity than the eye needs to recognize the general shape of the image.


Why Is Mesh Decimation So Important?

Mesh decimation plays a crucial role in 3D and augmented reality applications by reducing the size of 3D model files. Reducing the number of vertices, edges or faces composing an image simultaneously reduces the file size of the image.

Shrinking a 3D object requires a less powerful graphics processing unit (GPU) to display (render) its image on a device. It also accelerates how quickly the image can be sent from one device to another. By allowing images to be rendered and transmitted more efficiently, mesh decimation enables delivery of user-friendly 3D images and augmented reality experiences through ecommerce applications over media such as the Internet, social media, game engines and non-fungible tokens (NFTs).


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How VNTANA’s Algorithm Optimizes Mesh Decimation

The VNTANA platform uses a proprietary, patented optimization algorithm to deliver optimized 3D modeling. The algorithm interprets the shape of the model prior to decimation in order to ensure that the resulting image remains true to the appearance of the original 3D model. Based on its analysis, the algorithm can instantly remove vertices, collapse edges or collapse triangles to automatically reduce file size up to 99%.

VNTANA’s algorithm includes a feature that can toggle between views of an object with mesh areas not visible to the viewer (obstructed geometry) present or removed. This enables you to create expanded views of a model, showcase fine details or provide a zoomed-in view.


Use Mesh Decimation to Optimize Your Images for a Superior AR Experience

Mesh decimation simplifies the shape of 3D objects by reducing the number of vertices, edges or faces which define polygonal surfaces. This reduces file size, allowing 3D assets to be processed and downloaded more quickly. Efficient mesh decimation is critical for delivering 3D and augmented reality experiences in real-time for ecommerce applications.

Using the right technology is essential for optimal mesh decimation. The VNTANA platform’s propriety mesh decimation algorithm is designed to interpret model shapes before decimation to preserve image accuracy when resizing files for quick-loading across the web, social media, game engines, NFTs and other media. To get in touch with one of our Augmented Reality and 3D specialists, reach out to us here.