search for: quadrilateral

Hello, The following code produces a quadrilateral: q<-matrix(c(1,3,1,2,3,1,2,4,2,1,4,2),nrow=4,byrow=T) qc<-xyz.coords(q) wireframe(z~y*x,qc) I have 2 questions 1) How can i remove the bounding box i.e the cube encompassing the quadrilateral? 2) Is there any function to get the 2D coordinates of the quadrilateral actually use...

...th the function persp3d(rgl). for example z=rbind(c(1,NA,NA,NA),c(5,3,NA,NA),c(4,2,9,NA),c(8,6,5,11)) x=1:4 y=1:4 persp3d(x,y,z,color="gray") The two extreme points are not plotted (value=1 and value=10). It seems because the half of the matrix have 'NA' and perp3d need planar quadrilateral face. So I decided to use the function triangle3d to integrate these points into the scene. So, for the first point I did : triangles3d(x=c(1,2,2),y=c(1,1,2),z=c(1,5,3)) and it worked But a problem remains because the light movment on this triangle looks independant and I did not find how to sol...

Does anyone have any suggestions on perspective plotting of piecewise constant functions? Ideally, I would like something like plot.stepfun for functions that are piecewise constant on polygons. Even pointers to non-R strategies would be welcome at this stage. url: www.econ.uiuc.edu Roger Koenker Dept. of Economics UCL, email rkoenker at uiuc.edu Department of Economics Drayton House, vox:

Hi all, I'm quite new to wireframe, essentially what I want to do is display a graph, and z-values > 1 would be yellow and those < 1 would be blue. This is a bit of my data. 0.334643563 0.350913807 0.383652307 0.370325283 0.38779016 0.42387392 0.39861579 0.418389687 0.460692165 0.43888516 0.468015843 0.520560489 0.499544084 0.535099422 0.60982153 0.569888047 0.634351734

Thank you. Guess it's a plausible explanation. > -----Original Message----- > From: Liaw, Andy [mailto:andy_liaw at merck.com] > Sent: Tuesday, December 03, 2002 08:05 AM > To: 'Chunlou Yung' > Subject: RE: [R] Plotting Speed: R vs Octave > > > If I'm not mistaken, Octave does not have its own graphics system, but > rather rely on gnuplot, which is

What is the simplest (namely: minimum number of libraries or conflicts) way to fill a polygon with a pattern? For example, suppose I have (in a graphic file, like a jpeg) the drawing of an "X". Then I fill a polygon (like a triangle) with this pattern, and get something like: X XXX XXXXX XXXXXXX (where the border "X"s could be truncated). I searched the rimage

Dearl list, can anyone point me to a function or library that can create a graph similar to the one in the following powerpoint presentation? http://bmi.osu.edu/~khuang/IBGP705/BMI705-Lecture7.ppt (pages 36-37) In order to try to explain the graph, the way I see it in R terms is something like this: the "p-q" axis is a vector of positions (for example, seq(0,5000000,1)) the

Hi all, I am considering writing a 3D visualisation package for R. Purposes: - Visualise 3 dimension data - Manipulate the data or series or any other object with the mouse as in any 3D software (3D Studio Max, Lightwave...) - Eventually display more than just 3D objects. Justification: - It's always interesting to plot data before performing any analysis - Manipulating (rotating,

Dear all, is there any function to calculate the center of a polygon mass in R? Actually I need to find the best location within polygons to place labels. Thanks for any hint Jens Oehlschl?gel -- COMPUTERBILD 15/03: Premium-e-mail-Dienste im Test\ --------...{{dropped}}

...----------------- # step 00 : plot preparation # --------------------------------- # at the outset define some functions: three for # displaying shrouds and two for plotting axes # --------------------------------- # function : quad # --------------------------------- # description : generate quadrilateral from four "flat" vertices # role : called by function 'rect' # caution : the 'OpenGL' graphics library uses homogeneous, # not Euclidean, coordinates # status : complete # # Typical input uses Euclidean coordinates # # vertices (...

...try to adapt this, but before I do, I wonder >> if something like this for >> rgl exists that I haven't found. >> > > ?quads3d > > It's harder than that, because a plane intersecting with the bounding box of the data doesn't necessarily produce a quadrilateral: some are other polygons (e.g. an intersection near a corner can be a triangle). Plus, you want to still see a plane if you add new data and change the bounding box. So this is something that really needs to be done at the C++ level, and though I've wanted one every now and then, I'v...