Voxel is a relatively new terminology mostly associated with additive manufacturing or 3D printing. Most of us are not familiar with the term voxel. And most of us can’t differentiate between pixels and voxels. Voxels are closely related to pixels but still are quite different from it. While everyone using a smartphone, a digital camera or an LED televisions is familiar with pixel, Voxel is mostly out of people’s vocabulary.
Here, in this article we explain the difference between pixel and voxel.
Difference between Pixel and Voxel
Pixels
Pixel is the smallest unit of a digital graphic which can be illuminated on a display screen and a set of such illuminated pixels form an image on screen. A pixel is usually represented as a square or a dot on any display screen like a mobile, TV, or computer monitor. They can be called as the building blocks of a digital image and can be controlled to accurately show the desired picture.
The quality of picture concerning the clarity, size and colour combination is majorly controlled by the amount and density of pixels present in the display. Higher the resolution smaller the size of the pixel and better the clarity and vice versa.
Each pixel has a unique geometric co-ordinate, dimensions (length and breadth), size (eight bits or more), and has the ability to project multitude of colours.
Voxels
Voxels are fairly complicated to understand but can be defined in the easiest of language as a Volumetric Pixel. In 3D printing, we can define a voxel as a value on a grid in a three-dimensional space, like a pixel with volume. Each voxel contains certain volumetric information which helps to create a three dimensional object with required properties.
Voxel is the smallest distinguishable element of any 3D printed object and represents a certain grid value. However, unlike a pixel, voxel does not have a specific position in three-dimensional space. They are not bound by absolute coordinates but are defined by the relative position of the surrounding voxels. We can equate a voxel to bricks, where the position of a brick is defined by the relative position of the neighbouring bricks.
One important aspect of every voxel is the ability of repeatability. Voxels have a defined shape and size and can be stacked over each other to create a 3D object. A voxel need not be a cube, in fact it can be found in many forms like a spherical, triangle, square, rectangle, diamond, etc. as long as they follow the principal rule of repeatability
Difference between Pixel and Voxel
| Parameter | Pixel | Voxel |
| Dimensions | Two-dimensional | Three-dimensional |
| Position | Absolute position is known | Relative position is known |
| Volume | Pixel does not have volume | Voxel has a volume and hence also called as ‘Volumetric Pixel’. |
Why are Voxels useful?
Voxels provide some inherent advantages. They are as follows:
- Voxels are essential building block of any 3D object from the simple fact that they contain important information like density, opacity, colour and volumetric flow rate. This information is highly useful for analysing scientific and medical data from machines like CT Scanners and ultrasound. It is important even in the animation and game developments to design terrains.
- Voxels are self-aligning as long as they are in the vicinity of their final position.
- It is given that digital parts are highly repeatable. A digital file printed out in one part of the world must be exactly similar to the same file printed out somewhere else. This is achieved only because of voxels. Since voxels have the ability to store specific information with the power of repeatability, it is able to replicate the design and maintain consistency in designing.
- Voxels can be found in many shapes. Some shapes have advantage of faster printing while others can improve quality. Regular cubes or triangle voxels can help in faster printing but may lack in quality and vice versa. This helps in customisation by achieving the perfect trade-off.
- Voxel level research is very important for achieving the next step of customisation. Currently, we can use only a single resolution voxel in printing but control over the resolution of individual voxel can yield phenomenal results.
Voxel-Level 3D Printing
Voxels are the basics of any three-dimensional object. And gaining control over the voxel or attaining voxel-level control over 3D printing is the direction towards which the technology is moving. Voxel-level 3D printing is the ability to control each and every voxel in a 3D print.
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