I have decided to contact Dr. David H. Eberly, which is referenced as the source upon which the author in the first link I provided based himself upon. Dr. Eberly was kind enough to write an extensive reply. If I may quote part of it:
I already asked for that sample source code and am yet to...
This seems like a reasonable attempt:
z=a*t + thickness*cos(u)
x=(r+thickness*cos(u))*cos(w*t)
y=(r+thickness*cos(u))*sin(w*t)
For a surface you'll need two parameters u and t of course.
I managed to isolate a specific incident where this happens in my code. The distance between segments P1P2 and Q1Q2 changed abruptly in one timestep from 1.05 mm to 0.90 mm (yarn radius = 1 mm), causing abrupt compression spikes. In reality the distance in the original timestep is definitely...
Does anyone know a good algorithm for calculating the closest points/distance between two line segments? I use some pretty general code:
http://geomalgorithms.com/a07-_distance.html
which works in most cases but fails horribly when line segments are nearly parallel. I've been messing with the...
I did not fully solve it, I managed to find a way around that is not physically 100% correct. Around my point mass, I started to look for wedge surfaces and if sum of the distances between mass point and the two wedge surfaces fell between some treshold, started generating penalizing compressive...
Hi, kind of stuck with how to calculate frictional forces in a particular problem: I am modeling yarn using mass spring system, zero dimensional nodes. Question is, what to do when a yarn can get stuck between a wedge?
How to calculate friction force vector, surface reaction and so? Since a...
Theoretical question with practical implications (trying to model yarn as mass points connected with spring systems and need to get collision response with objects right):
A mass point approaches a plate under an angle. You have the coefficient of restitution β and the friction coefficient μ...
Hi, I've gotten the conjugate gradient method to work for solving my matrix equation:
http://en.wikipedia.org/wiki/Conjugate_gradient_method
Right now I'm experimenting with the preconditioned version of it. For a certain preconditioner however I'm finding that
is zero, so no proper update...
Quoting from memory:
The enriched uranium was actually there under UN supervision until the weapons inspectors left, so the war made proliferation actually a BIGGER risk Fortunately, it wasn't looted and even if it was, it was not all that highly enriched and I think enough for only half a...
Hello,
The standard deviation is calculated as:
http://www.mathsrevision.net/gcse/sdeviation2.gif
Now the problem I have is that how you calculate the standard deviation (more accurately?) over both samplesvif you have two samples of different size, n1 and n2, in which the level of the...
Do you know of code (preferably C/C++) to do this for non linear least squares? i found a program called levmar on the internet, but it seems inadequately documented on how to use it and probably not so useful to my purposes.
My problem is evaluation of a carpet. The middle is worn out and it...
Sorry, I'm being a bit overwhelmed. No I don't know those things. I do suspect the equations of motion used for the object are alright but the interaction with the yarn is at fault. The yarn is discretized in a number of 0-dimensional nodes. I have discovered a flaw in my modeling though. I have...
Hello,
I am currently trying to simulate an object that can rotate around an axis bouncing on a piece of yarn. I have as equations of motion for the object:
I d²Theta/dt² = Gravity_Torque + Yarn_Torque
With the gravity torque alone this system is perfectly conserving energy: the...
Now I know the chance that self ignition of Jupiter has less chances than a snowball has to survive in hell. Have there been however serious studies towards the possibility or impossibility of triggering ignition? If the density (Lawson's criterion) and chemical composition (not too many heavier...
Not exactly what I was looking for, but thanks for the effort. I've in the meantime found some more relevant publications like by Sachin Goyal, http://www-personal.engin.umich.edu/~sgoyal/mypapers/DETC2003-MECH-48322.PDF , that listen closer to my interest. It's one of his other ones which...