Voxel is a relatively new terminology and mostly associated with additive manufacturing or 3D printing. Most of us are not familiar with the term voxel. Voxels are closely related to pixels but are quite different from one other. While everyone using a smartphone or a digital camera or even LED televisions is familiar with pixel, Voxel is mostly restricted to the professionals concerned with additive manufacturing or 3D printing.
Here, we explain the term voxel and the difference between pixel and voxel.
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 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.
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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
Absolute position is known
Relative position is known
Pixel does not have volume
Voxel has a volume. Often called as ‘Volumetric Pixel’
Why are voxels useful?
Voxels provide some inherent advantages. They are as follows:
1. 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.
2. Voxels are self-aligning as long as they are in the vicinity of their final position.
3. 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.
4. 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.
5. 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.
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