geometry-surface

问题 Finding the intersection of the Circle and Infinite Cylinder. (all in 3D) • Circle is defined by center, plane in which it lies and radius. • Cylinder is defined by axis and radius. how can i get the intersection of these two? 回答1: WLOG the cylinder has equation X² + Y² = 1 (if not, you can make it so by translation, rotation and scaling). Then the parametric equation of the circle is P = C + U cos t + V sin t where C is the center point and U , V two orthogonal vectors in the circle plane,

问题 I'm trying to get my webcam to show video through pygame. Here is the code: # import the relevant libraries import time import pygame import pygame.camera from pygame.locals import * # this is where one sets how long the script # sleeps for, between frames.sleeptime__in_seconds = 0.05 # initialise the display window pygame.init() pygame.camera.init() screen = pygame.display.set_mode((640, 480), 0, 32) # set up a camera object cam = pygame.camera.Camera(0) # start the camera cam.start() while

问题 I found this website where you try drawing a perfect circle. Just for fun I coded this small Java application, that draws a circle from the middle of your screen: // here is my massive array private static int[] circle = {0, -100, 1, -100, 2, -100, 3, -100, 4, -100, 5, -100, 6, -100, 7, -100, 8, -100, 9, -100, 10, -100, 11, -99, 12, -99, 13, -99, 14, -99, 15, -99, 16, -99, 17, -98, 18, -98, 19, -98, 20, -98, 21, -98, 22, -97, 23, -97, 24, -97, 25, -97, 26, -96, 27, -96, 28, -96, 29, -96, 30,

问题 I found this website where you try drawing a perfect circle. Just for fun I coded this small Java application, that draws a circle from the middle of your screen: // here is my massive array private static int[] circle = {0, -100, 1, -100, 2, -100, 3, -100, 4, -100, 5, -100, 6, -100, 7, -100, 8, -100, 9, -100, 10, -100, 11, -99, 12, -99, 13, -99, 14, -99, 15, -99, 16, -99, 17, -98, 18, -98, 19, -98, 20, -98, 21, -98, 22, -97, 23, -97, 24, -97, 25, -97, 26, -96, 27, -96, 28, -96, 29, -96, 30,

来源： https://stackoverflow.com/questions/62040262/how-to-make-a-3d-surface-plot-with-matplotlib-z-is-not-calculated-by-func

来源： https://stackoverflow.com/questions/62040262/how-to-make-a-3d-surface-plot-with-matplotlib-z-is-not-calculated-by-func

问题 Dear fellow stackoverflow users, I face a problem as follows: I would like to fit a 3D ellipsoid to 3D data points within my python script. The starting data are a set of x, y and z coordinates (cartesian coordinates). What I would like to get are a and c in the defining equation of the best-fit ellipsoid of the convex hull of the 3D data points. The equation is, in the properly rotated and translated coordinate system: So the tasks I would ideally like to do are: Find convex hull of 3D data

问题 I have in mind this video, or this simulation, and I would like to reproduce the geodesic lines on some sort of surface in 3D, given by a function f(x,y), from some starting point. The midpoint method seems computationally and code intense, and so I'd like to ask if there is a way to generate an approximate geodesic curve based on the normal vector to the surface at different points. Each point has a tangent vector space associated with it, and therefore, it seems like knowing the normal

问题 In the following code, there is not just one circle on the screen at any given point in time. I want to fix this to make it so that it looks like there is only one circle, instead of leaving a smudge trail where ever the mouse cursor has been. import pygame,sys from pygame.locals import * pygame.init() screen = pygame.display.set_mode((640,400),0,32) radius = 25 circle = pygame.Surface([radius*2]*2,SRCALPHA,32) circle = circle.convert_alpha() pygame.draw.circle(circle,(25,46,100),[radius]*2

问题 In the following code, there is not just one circle on the screen at any given point in time. I want to fix this to make it so that it looks like there is only one circle, instead of leaving a smudge trail where ever the mouse cursor has been. import pygame,sys from pygame.locals import * pygame.init() screen = pygame.display.set_mode((640,400),0,32) radius = 25 circle = pygame.Surface([radius*2]*2,SRCALPHA,32) circle = circle.convert_alpha() pygame.draw.circle(circle,(25,46,100),[radius]*2