Low poly
Encyclopedia
Low poly is a term used to describe a polygon mesh
in 3D computer graphics
which has a small number of polygons. It is, however, a relative term, usually referring to meshes in real-time applications (e.g. games). That is to contrast them with meshes in animated movies and special effects of the same era (high poly). The term low poly is used in both a technical and a descriptive sense; the number of polygons in a mesh is an important factor to optimize for performance
but can give an undesirable appearance to the resulting graphics
.
s for display. In general the more triangles in a mesh the more detailed the object is, but the more computationally intensive it is to display. In order to decrease render times (i.e. increase frame rate) the number of triangles in the scene must be reduced, by using low poly meshes.
or rendering method and the computer being used defines the polygon budget; the number of polygons which can appear in a scene and still be rendered at an acceptable frame rate. Therefore the use of low poly meshes are mostly confined to computer games and other software a user must manipulate 3D objects in real time because processing power is limited to that of a typical personal computer
or games console and the frame rate must be high. Computer generated imagery for, for example, films or still images have a higher polygon budget because rendering does not need to be done in real-time, which requires higher frame rates. In addition, computer processing power in these situations is typically less limited, often using a large network of computers or what is known as a render farm
. Each frame can take hours to create, despite the enormous computer power involved. A common example of the difference this makes is full motion video
sequences in computer games which, because they can be pre-rendered, and look much smoother than the games themselves.
Computer graphics techniques such as normal
and bump mapping
have been designed to make a low poly object appear to contain more polygons than it does. This is done by altering the shading of polygons to contain internal detail which is not in the mesh.
As computing power inevitably increases, the number of polygons that can be used increases too. For example, Super Mario 64
would be considered low poly today, but was considered a stunning achievement when it was released in 1996. Similarly, in 2009, using hundreds of polygons on a leaf in the background of a scene would be considered high poly, but using that many polygons on the main character would be considered low poly.
s have presented a new role for low poly meshes. Whilst the display of computer graphics has become very efficient, allowing (as of 2009) the display of tens to hundreds of thousands of polygons at 25 frames per second on a desktop computer, the calculation of physical interactions is still slow. A low poly simplified version of the mesh is often used for simplifying the calculation of collision
s with other meshes, in some cases this is as simple as a 6 polygon bounding box.
Polygon mesh
A polygon mesh or unstructured grid is a collection of vertices, edges and faces that defines the shape of a polyhedral object in 3D computer graphics and solid modeling...
in 3D computer graphics
3D computer graphics
3D computer graphics are graphics that use a three-dimensional representation of geometric data that is stored in the computer for the purposes of performing calculations and rendering 2D images...
which has a small number of polygons. It is, however, a relative term, usually referring to meshes in real-time applications (e.g. games). That is to contrast them with meshes in animated movies and special effects of the same era (high poly). The term low poly is used in both a technical and a descriptive sense; the number of polygons in a mesh is an important factor to optimize for performance
Computer performance
Computer performance is characterized by the amount of useful work accomplished by a computer system compared to the time and resources used.Depending on the context, good computer performance may involve one or more of the following:...
but can give an undesirable appearance to the resulting graphics
Computer graphics
Computer graphics are graphics created using computers and, more generally, the representation and manipulation of image data by a computer with help from specialized software and hardware....
.
Motivation for low poly meshes
Polygon meshes are one of the major methods of modelling a 3D object for display by a computer. Polygons can, in theory, have any number of sides but are commonly broken down into triangleTriangle
A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ....
s for display. In general the more triangles in a mesh the more detailed the object is, but the more computationally intensive it is to display. In order to decrease render times (i.e. increase frame rate) the number of triangles in the scene must be reduced, by using low poly meshes.
Polygon budget
A combination of the game engineGame engine
A game engine is a system designed for the creation and development of video games. There are many game engines that are designed to work on video game consoles and personal computers...
or rendering method and the computer being used defines the polygon budget; the number of polygons which can appear in a scene and still be rendered at an acceptable frame rate. Therefore the use of low poly meshes are mostly confined to computer games and other software a user must manipulate 3D objects in real time because processing power is limited to that of a typical personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
or games console and the frame rate must be high. Computer generated imagery for, for example, films or still images have a higher polygon budget because rendering does not need to be done in real-time, which requires higher frame rates. In addition, computer processing power in these situations is typically less limited, often using a large network of computers or what is known as a render farm
Render farm
A render farm is a computer cluster built to render computer-generated imagery , typically for film and television visual effects, using off-line batch processing. This is different from a render wall, which is a networked, tiled display used for real-time rendering...
. Each frame can take hours to create, despite the enormous computer power involved. A common example of the difference this makes is full motion video
Full motion video
Full motion video based games are video games that rely upon pre-recorded TV-quality movie or animation rather than sprites, vectors, or 3D models to display action in the game. In the early 1990s a diverse set of games utilized this format...
sequences in computer games which, because they can be pre-rendered, and look much smoother than the games themselves.
Appearance of low poly meshes
Objects that are said to be low poly often appear blocky (such as square heads) and lacking in detail (such as no individual fingers). Objects that are supposed to be circular or spherical are most obviously low poly as the number of triangles needed to make a curve appear smooth is high and polygons are restricted to straight edges. Low poly meshes do not necessarily look bad, for example a flat sheet of paper represented by one polygon looks extremely accurate.Normal mapping
In 3D computer graphics, normal mapping, or "Dot3 bump mapping", is a technique used for faking the lighting of bumps and dents. It is used to add details without using more polygons. A common use of this technique is to greatly enhance the appearance and details of a low polygon model by...
and bump mapping
Bump mapping
Bump mapping is a technique in computer graphics for simulating bumps and wrinkles on the surface of an object. This is achieved by perturbing the surface normals of the object and using the perturbed normal during lighting calculations. The result is an apparently bumpy surface rather than a...
have been designed to make a low poly object appear to contain more polygons than it does. This is done by altering the shading of polygons to contain internal detail which is not in the mesh.
Low poly as a relative term
There is no defined threshold for a mesh to be low poly; low poly is always a relative term and depends on (amongst other factors):- The time the meshes were designed and for what hardwareHardwareHardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....
- The detail required in the final mesh
- The shape and properties of the object in question
As computing power inevitably increases, the number of polygons that can be used increases too. For example, Super Mario 64
Super Mario 64
is a platform game, published by Nintendo and developed by its EAD division, for the Nintendo 64. Along with Pilotwings 64, it was one of the launch titles for the console. It was released in Japan on June 23, 1996, and later in North America, Europe, and Australia. Super Mario 64 has sold over...
would be considered low poly today, but was considered a stunning achievement when it was released in 1996. Similarly, in 2009, using hundreds of polygons on a leaf in the background of a scene would be considered high poly, but using that many polygons on the main character would be considered low poly.
Low poly meshes in physics engines
Physics enginePhysics engine
A physics engine is computer software that provides an approximate simulation of certain physical systems, such as rigid body dynamics , soft body dynamics, and fluid dynamics, of use in the domains of computer graphics, video games and film. Their main uses are in video games , in which case the...
s have presented a new role for low poly meshes. Whilst the display of computer graphics has become very efficient, allowing (as of 2009) the display of tens to hundreds of thousands of polygons at 25 frames per second on a desktop computer, the calculation of physical interactions is still slow. A low poly simplified version of the mesh is often used for simplifying the calculation of collision
Collision
A collision is an isolated event which two or more moving bodies exert forces on each other for a relatively short time.Although the most common colloquial use of the word "collision" refers to accidents in which two or more objects collide, the scientific use of the word "collision" implies...
s with other meshes, in some cases this is as simple as a 6 polygon bounding box.
See also
- Polygon (computer graphics)Polygon (computer graphics)Polygons are used in computer graphics to compose images that are three-dimensional in appearance. Usually triangular, polygons arise when an object's surface is modeled, vertices are selected, and the object is rendered in a wire frame model. This is quicker to display than a shaded model; thus...
- Bump mappingBump mappingBump mapping is a technique in computer graphics for simulating bumps and wrinkles on the surface of an object. This is achieved by perturbing the surface normals of the object and using the perturbed normal during lighting calculations. The result is an apparently bumpy surface rather than a...
- Normal mappingNormal mappingIn 3D computer graphics, normal mapping, or "Dot3 bump mapping", is a technique used for faking the lighting of bumps and dents. It is used to add details without using more polygons. A common use of this technique is to greatly enhance the appearance and details of a low polygon model by...
- SpritesSprite (computer graphics)In computer graphics, a sprite is a two-dimensional image or animation that is integrated into a larger scene...
- Nurbs