About the code of sphere 3D ratation in yade

Hello,

please be more specific.

> I want to call the pose shapes of the particles and their 3D rotations at each time step.

what does this, specifically "call pose shapes" exactly mean?

> But I didn't find code that handles 3D rotation of spherical particles.

what does "handle 3D rotation" mean?

The orientation / 3D rotation of particle is in python its b.state.ori, so the corresponding C++ code is inside core/State.hpp

It's main "usage" is probably in NewtonIntegrator, so ha a look there, pkg/dem/NewtonIntegrator.*
See also explanation in documentation [1]

b.state.ori is a quaternion [2].

Cheers
Jan

[1] https://yade-dem.org/doc/formulation.html#motion-integration , section Orientation
[2] https://en.wikipedia.org/wiki/Quaternion

Thanks for your reply, Jan!

>the mean is I want to the declear of quaternion and other parapmeter in C++ code, which are used to defined the 3D rotation. so I can call those parameter. And I have found the code in pkg/dem/NewtonIntegrator.* and Yade documentation.

>I'm learning a little bit about 3D ratation, and there are four ways to represent 3D ratation: Euler angle, aixs-angle, ratation matrix and quaternion[3]. However, I can't understand the code in pkg/dem/NewtonIntegrator.cpp as follow:

void NewtonIntegrator::leapfrogSphericalRotate(State* state, const Real& dt)
{
 if (scene->isPeriodic && homoDeform) { state->angVel += dSpin; }
 Real angle2 = state->angVel.squaredNorm();
 if (angle2 != 0) { //If we have an angular velocity, we make a rotation
  Real angle = sqrt(angle2);
  Quaternionr q(AngleAxisr(angle * dt, state->angVel / angle));
  state->ori = q * state->ori;
 }
 state->ori.normalize();
}

There are used the quaternion but the calculate method of quaternion is different from [3]. Could you help me explain this code? and from thoretical method to code implementatyion process.

Shenyu

[3]https://www.euclideanspace.com/maths/geometry/rotations/theory/index.htm

> I can't understand the code
> Could you help me explain this code?

Please be more specific, which part of code you do not understand (specific line, whole function, ...)

> There are used the quaternion but the calculate method of quaternion is different from [3]

Please be more specific, e.g. what is "calculate method of quaternion"

Cheers
Jan

This question was expired because it remained in the 'Needs information' state without activity for the last 15 days.