#computational-geometry

This Rhino Python code calculates the cross-product determinant used to determine the orientation of three points (current, next_point, and point) to see if they form a left turn or a right turn. This is a well-known technique in computational geometry to check the relative orientation of points. In this script, the direction is the cross-product determinant that determines the relative orientation of the points. If the result is negative, the point is to the right of the line from current…

Boris Nikolayevich Delaunay was a Russian mathematician and mountain climber. He developed the Delaunay triangulation, which is a method in computational geometry. It is a triangulation of a set of points such that no point is inside the circumcircle of any triangle formed by the points. It’s widely used in computer graphics and mesh generation. In 2013, I made the brute force code in Rhino Python which is a slow solution to this problem. It used to be a nice…

Again, I continue with some simple solutions for Grasshopper. The surface split component gives all possible surfaces sliced with given curves. And it creates “invalid” curves with at least one open edge. I used this to perceive the closed regions within a given complex curve set. Just put the “Clean” component to erase the outer invalid surfaces and there remain the closed ones. However this time the question was where to put the circle and what its radius of it…

This is a simple trick that shows the utilization of the “surface split” component in Grasshopper. It is used for detecting the inner regions of any given two-dimensional linework. Thus, it resembles the hatch boundary detection of AutoCAD and similar software. There is no built-in hatch component in Grasshopper. But maybe you can use this as a starting point if you want to develop it. The definition starts with drawing a circle around a point large enough. The size of…

Today’s tip is about two-dimensional curve-point calculations. It is very handy to use “closest point” components in Grasshopper. You can calculate distances and directions between curves, surfaces, and points. Then, place point objects in relation to the proximity of another object. However, there is no “farthest point” implemented yet. I tried to calculate the farthest point from a curve. First, I tried to translate the curve in a fashion that would result in the opposite of the closest point calculation….

When I was younger, among the branches of philosophy, I had studied a little logic and, among the subjects of mathematics, geometrical analysis and algebra, three arts or sciences which looked as if they ought to contribute something to my project. But in looking at them, I took care, because, so far as logic is concerned, its syllogisms and most of its other instructions serve to explain to others what one already knows or even, as in the art of…

Here is the preface of the famous book “Architectural Geometry”. It simply encourages me to learn new things every day even sometimes it seems to become impossible. Geometry lies at the core of the architectural design process. It is omnipresent, from the initial form-finding stages to the actual construction. Modern constructive geometry provides a variety of tools for the efficient design, analysis, and manufacture of complex shapes. This results in new challenges for architecture. However, the architectural application also poses…

Here are several passages from Shamos’s dissertation thesis, where he is studying the history of geometry from the perspective of a computer scientist. This topic always fascinated me. However, this is a good reading for the algorithmic roots of geometry. …Egyptian and Greek geometry were masterpieces of applied mathematics. It is well established that the original motivation for tackling geometric problems was the need to tax lands accurately and fairly and to erect buildings (Eves, 72)… Euclid’s chief contribution to…

…While it is true that every curve which can be described by a continuous motion should ve recognized in geometry, this does not mean that we should use at random the first one that we meet in the construction of a given problem. We should always choose with care the simplest curve that can be used in the solution of a problem, but it should be noted that the simplest means not merely the one most easily described, nor the…

This is the continuation of my scripting experiment within Grasshopper. Like the minimum spanning tree algorithm, this is also a famous problem of computational geometry; the shortest path problem. I’m now coding faster and understanding the namespace more easily in Grasshopper. This time, the challenge was implementing Dijkstra’s algorithm for the Shortest Path Generator. Again, it’s a quite powerful algorithm, I even plan to use it in my current project. Although there is a faster alternative, Shortest Walk-in Food4Rhino and it…