cylindrical

(new to stackoverflow, new to webgl/three.js, ...) I'm using three.js r54 to plot a force-directed graph. the edges between the nodes are THREE.Lines, which is fine, but lines are not selectable with a raycaster. so my aim is to take cylinders instead(/along with) of lines(also because I can do some further stuff: using textures,...) this is what I'm doing to place the cylinders: // init reference vector var upVec = new THREE.Vector3(0,1,0); //---withhin a loop--- // get direction var direction = startPoint.subSelf(endPoint).clone(); // half length for cylinder height var halfLength =

Because of your great help I can now plot a 3D cylinder with a hole inside :) This is my code: import numpy as np import matplotlib as mlp import matplotlib.pyplot as plt import mpl_toolkits.mplot3d.axes3d as axes3d inner_radius = 100 outer_radius = 300 height=50 # input xy coordinates input_xy = np.array([[ri,0],[ra,0],[ra,h],[ri,h],[ri,0]]) # radial component is x values of input r = xy[:,0] # angular component is one revolution of 30 steps phi = np.linspace(0, 2*np.pi, 30) # create grid R,Phi = np.meshgrid(r,phi) # transform to cartesian coordinates X = R*np.cos(Phi) Y = R*np.sin(Phi) # Z

I want to warp a flat image in a way that it appears to be the projection coming from a cylinder. I have a flat image like this: and I want to show it as something like this in 2D image: I'm a bit phased out on geometrical projections. I visited some other questions like this but I don't understand how will I represent these cylindrical coordinates (theta and rho) into x,y coordinates in cartesian (x,y) plane. Could you guys help me with an elaborative example? I'm coding it for iPhone and I'm not using any 3rd party library like OpenCV etc. Thanks a bunch. Hammer This is an answer in 2 parts,