Prev: R2010b Prerelease is Live
Next: mxCallMATLAB problems
From: Sahra winter on 7 Jun 2010 15:33 I have some spheres/points plotted in 3D & would like to give each of them a random motion? Any idea how to do that? any help is appreciated -Sahra
From: Walter Roberson on 7 Jun 2010 15:49 Sahra winter wrote: > I have some spheres/points plotted in 3D & would like to give each of > them a random motion? Any idea how to do that? Should the motion be constrained to a maximum Euclidean magnitude, or are x and y and z independent and constrained? Somewhere around 10 days ago, Roger Stafford showed how to create a random simplex, which is needed in order to construct vectors whose total magnitude is constrained; the naive methods tend to result in the corners (e.g., high x, low y, low z) being avoided.
From: Walter Roberson on 7 Jun 2010 17:57 Walter Roberson wrote: > Sahra winter wrote: >> I have some spheres/points plotted in 3D & would like to give each of >> them a random motion? Any idea how to do that? > > Should the motion be constrained to a maximum Euclidean magnitude, or > are x and y and z independent and constrained? Another question: what distribution of random values are you looking for? Should, for example, M*(1/10,3/22,1/50) and M*(1/sqrt(3),1/sqrt(3),1/sqrt(3)) be equally probable -- so any point with magnitude 0 to M should be equi-probable? Or should low velocities be more likely and velocity M should be the infinite limit of exponentially decreasing probabilities? Or should an average velocity of M/2 be more probable with a bell curve for the others? Should all ways of reaching a given velocity the same probability or should (for example) equal-magnitudes on the 3 axes be more probable than straight along one of the axes? Should a random radius (velocity) be taken and then a random point on a sphere be constructed to find the components of the individual magnitudes?
From: Sahra winter on 9 Jun 2010 00:14 Dear Walter: If possible the motion should be constrained to a max Euclidean magnitude (moving points/sphere should be constraint to a certain volume in space) Probability of any point with magnitude 0 to M does not have to be equi-probable. basically I just want to have some points/particle that are moving in a 3D volume... the purpose is to take a movie from a camera carried by one of the particles from others. How these particle move doesn't really matters, however the movements should be random.
From: Walter Roberson on 9 Jun 2010 01:14 Sahra winter wrote: > If possible the motion should be constrained to a max Euclidean > magnitude (moving points/sphere should be constraint to a certain > volume in space) http://mathworld.wolfram.com/SpherePointPicking.html
|
Pages: 1 Prev: R2010b Prerelease is Live Next: mxCallMATLAB problems |