What is a straight skeleton in geometry?
In geometry, a straight skeleton is a method of representing a polygon by a topological skeleton. It is similar in some ways to the medial axis but differs in that the skeleton is composed of straight line segments, while the medial axis of a polygon may involve parabolic curves. However, both are homotopy-equivalent to the underlying polygon.
What is the meaning of skeleton?
Kids Definition of skeleton 1 : a firm structure or framework of a living thing that in vertebrates (as fish, birds, or humans) is typically made of bone and supports the soft tissues of the body and protects the internal organs 2 : framework the steel skeleton of a building
What is the difference between 0 skeleton and 1 skeleton?
The 0-skeleton is a discrete space, and the 1-skeleton a topological graph. The skeletons of a space are used in obstruction theory, to construct spectral sequences by means of filtrations, and generally to make inductive arguments.
What is a skeleton model?
Skeleton models are parts that allow designers to pass along essential design information from one subsystem or assembly to another. There are many types of skeleton models, but for now, we will focus on a standard skeleton model. Other types of skeleton models, like motion skeleton models, contain standard skeletons to set design intent.
What is a skeleton in mathematics?
In mathematics, a skeleton of a category is a subcategory that, roughly speaking, does not contain any extraneous isomorphisms. In a certain sense, the skeleton of a category is the "smallest" equivalent category, which captures all "categorical properties" of the original.
What is the skeleton of a graph?
In algebraic topology, a -skeleton is a simplicial subcomplex of that is the collection of all simplices of of dimension at most , denoted . The graph obtained by replacing the faces of a polyhedron with its edges and vertices is therefore the skeleton of the polyhedron.
What is the 1 skeleton?
The 1-skeleton of a polyhedral surface is the set of edges and vertices of the surface. For example, the 1-skeleton of a cube is the set of twelve edges connecting the corners.
What is skeleton design?
Skeleton design, also known as ghost design, is a user experience technique that renders gray boxes on a page while the user is waiting for the real content to be loaded. This technique improves the sense of performance, and also avoids potential flickering of the UI. It often comes with an animation.
What is a proximity graph?
A proximity graph is a simply a graph in which two vertices are connected by an edge if and only if the vertices satisfy particular geometric requirements. ● “Proximity” here means spatial distance. ● Many of these graphs can be formulated with respect to many metrics, but the Euclidean metric is used most frequently.
Can a skeletons bow break?
When a skeleton shoots arrows from a bow, the bow uses up durability. Eventually, the bow will break. However, despite the bow breaking, the skeleton has its arms out as if it were shooting from a bow, but shoots arrows from its chest instead.
Can skeletons run out of arrows?
Can a Skeleton run out of arrows? If a skeleton is shooting tipped arrows, it will never run out.
Can skeletons drop Infinity bows?
Four enchantments have been added: Flame, Punch, Power and Infinity. Skeletons now have a 2.5% chance of dropping a bow.
How do you make a skeleton part?
1:355:35Creo Parametric - Skeletons - Top Down Design (Part 1) - YouTubeYouTubeStart of suggested clipEnd of suggested clipOption I'm going to use copy from existing. And use my standard start. Part. Now when I expand theMoreOption I'm going to use copy from existing. And use my standard start. Part. Now when I expand the sub assembly I see the skeleton. Model let's click on the skeleton. And then activate it.
What is code skeleton to the design?
Skeleton programming is a style of computer programming based on simple high-level program structures and so called dummy code. Program skeletons resemble pseudocode, but allow parsing, compilation and testing of the code.
Why do skeletons load?
A skeleton screen is an animated placeholder that simulates the layout of a website while data is being loaded. They let the user know that some content is loading and, more importantly, provide an indication of what is loading, whether it's an image, text, card, and so on.
What is called skeleton?
The skeletal system is your body's central framework. It consists of bones and connective tissue, including cartilage, tendons, and ligaments. It's also called the musculoskeletal system.
What is the function of skeleton?
facilitates movement. protects internal organs. produces blood cells. stores and releases minerals and fat.
What are the 3 types of skeletons?
There are three different skeleton designs that fulfill these functions: hydrostatic skeleton, exoskeleton, and endoskeleton.
What are the 2 types of skeleton?
The adult human skeleton usually consists of 206 named bones. These bones can be grouped in two divisions: axial skeleton and appendicular skeleton.
What is a skeleton model?
Skeleton models are parts that allow designers to pass along essential design information from one subsystem or assembly to another. There are many types of skeleton models, but for now, we will focus on a standard skeleton model. Other types of skeleton models, like motion skeleton models, contain standard skeletons to set design intent.
Why are Skeleton Models Unique?
Creo gives it a special designation of being a “skeleton” so that other individual parts can reference it without having to go through the process of an external reference. As explained in “Working with External References”, if an engineer does not use a skeleton part, they would have to use external references, causing the model to load unnecessary assemblies and components to find the correct reference.
Why are skeleton models excluded from mass and surface properties?
Because skeleton models are a nonsolid part, they are excluded from mass and surface properties as well as Bill of Materials. This makes skeleton models unique from regular parts.
What is the purpose of skeleton models?
Being at the “top” of your top-down design, you can use standard skeleton models to identify datums and surfaces that will indicate where to place individual components within your assembly levels.
Why do skeleton models have to be oriented and placed correctly?
Skeleton models have to be oriented and placed correctly in order to line up in the right way. Datums and surfaces allow engineers to orient and place parts more accurately.
Why is it important to have a skeleton model?
Skeleton models can improve how engineers do top-down design. As models become more complex, it becomes increasingly important to have clear best practices for skeleton models. By doing so, you can eliminate hours of wasted time loading extraneous assemblies or re-linking subassemblies.
Is a component a part or a part?
A component is a child of a parent assembly, while a part is a standalone, singular object. A component can be either a part (PRT) or an assembly (ASM). For example, D.PRT by itself is just a part.
What is a skeleton?
Definition of skeleton. (Entry 1 of 2) 1 : a usually rigid supportive or protective structure or framework of an organism especially : the bony or more or less cartilaginous framework supporting the soft tissues and protecting the internal organs of a vertebrate. 2 : something reduced to its minimum form or essential parts.
What is a skeleton in a sentence?
Examples of skeleton in a Sentence. Noun They found the fossil skeleton of a mastodon. He hung a plastic skeleton on the door for Halloween. She was a skeleton after her illness. Only the charred skeleton of the house remained after the fire. We saw a skeleton of the report before it was published. See More.
What does "skellein" mean in Latin?
New Latin, from Greek, neuter of skeletos dried up; akin to Greek skellein to dry up, sklēros hard and perhaps to Old English sceald shallow
What is the definition of a vertebrate?
1 : a usually rigid supportive or protective structure or framework of an organism especially : the bony or more or less cartilaginous framework supporting the soft tissues and protecting the internal organs of a vertebrate.
What is the definition of a framework?
1 : a firm structure or framework of a living thing that in vertebrates (as fish, birds, or humans) is typically made of bone and supports the soft tissues of the body and protects the internal organs. 2 : framework the steel skeleton of a building.
How to define a straight skeleton?
The straight skeleton of a polygon is defined by a continuous shrinking process in which the edges of the polygon are moved inwards parallel to themselves at a constant speed. As the edges move in this way, the vertices where pairs of edges meet also move, at speeds that depend on the angle of the vertex. If one of these moving vertices collides with a nonadjacent edge, the polygon is split in two by the collision, and the process continues in each part. The straight skeleton is the set of curves traced out by the moving vertices in this process. In the illustration the top figure shows the shrinking process and the middle figure depicts the straight skeleton in blue.
What is a straight skeleton?
In geometry, a straight skeleton is a method of representing a polygon by a topological skeleton. It is similar in some ways to the medial axis but differs in that the skeleton is composed of straight line segments, while the medial axis of a polygon may involve parabolic curves. However, both are homotopy-equivalent to the underlying polygon.
When were straight skeletons first defined?
Straight skeletons were first defined for simple polygons by Aichholzer et al. (1995) , and generalized to planar straight-line graphs (PSLG) by Aichholzer & Aurenhammer (1996). In their interpretation as projection of roof surfaces, they are already extensively discussed by G. A. Peschka ( 1877 ).
Who defined a version of straight skeletons for three-dimensional polyhedra?
Barequet et al. defined a version of straight skeletons for three-dimensional polyhedra, described algorithms for computing it, and analyzed its complexity on several different types of polyhedron.
What is monotone polygon?
A monotone polygon with respect to a line L is a polygon with the property that every line orthogonal to L intersects the polygon in a single interval. When the input is a monotone polygon, its straight skeleton can be constructed in time O ( n log n ).
Why are skeletons important?
They are particularly important when X has infinite dimension, in the sense that the Xn do not become constant as n → ∞.
What is the n-skeleton of a topological space?
In mathematics, particularly in algebraic topology, the n-skeleton of a topological space X presented as a simplicial complex (resp. CW complex) refers to the subspace Xn that is the union of the simplices of X (resp. cells of X) of dimensions m ≤ n. In other words, given an inductive definition of a complex, the n-skeleton is obtained by stopping at the n-th step .
What is the k-skeleton of a polytope?
In geometry, a k-skeleton of n- polytope P (functionally represented as skel k ( P )) consists of all i-polytope elements of dimension up to k.
Overview
In geometry, a straight skeleton is a method of representing a polygon by a topological skeleton. It is similar in some ways to the medial axis but differs in that the skeleton is composed of straight line segments, while the medial axis of a polygon may involve parabolic curves. However, both are homotopy-equivalent to the underlying polygon.
Straight skeletons were first defined for simple polygons by Aichholzer et al. (1995), and generali…
Definition
The straight skeleton of a polygon is defined by a continuous shrinking process in which the edges of the polygon are moved inwards parallel to themselves at a constant speed. As the edges move in this way, the vertices where pairs of edges meet also move, at speeds that depend on the angle of the vertex. If one of these moving vertices collides with a nonadjacent edge, the polygon is split in two by the collision, and the process continues in each part. The straight skele…
Algorithms
The straight skeleton may be computed by simulating the shrinking process by which it is defined; a number of variant algorithms for computing it have been proposed, differing in the assumptions they make on the input and in the data structures they use for detecting combinatorial changes in the input polygon as it shrinks.
The following algorithms consider an input that forms a polygon, a polygon with holes, or a PSL…
Applications
Each point within the input polygon can be lifted into three-dimensional space by using the time at which the shrinking process reaches that point as the z-coordinate of the point. The resulting three-dimensional surface has constant height on the edges of the polygon, and rises at constant slope from them except for the points of the straight skeleton itself, where surface patches at different angles meet. In this way, the straight skeleton can be used as the set of ridge lines of a …
Higher dimensions
Barequet et al. defined a version of straight skeletons for three-dimensional polyhedra, described algorithms for computing it, and analyzed its complexity on several different types of polyhedron.
Huber et al. investigated metric spaces under which the corresponding Voronoi diagrams and straight skeletons coincide. For two dimensions, the characterization of such metric spaces is complete. For higher dimensions, this method can be interpreted as a generalization of straight …
External links
• Erickson, Jeff. "Straight Skeleton of a Simple Polygon".
• 2D Straight Skeleton in CGAL, the Computational Geometry Algorithms Library
• Straight Skeleton for polygon with holes Straight Skeleton builder implemented in java.