[Deepblack]

Hi,
A few words about my project:
I need to reflect a moving objekt, before it 'leaves my mesh'. And therefore i want to negate one component of the velocity.

Thats why i want to access the velocity in a 6DoF UDF. Is there any kind of syntax to do so?
I have tried to use:
SDOF_Get_Motion(dt,vel,omega,theta);
... but i get the error that says something like "This value isn't calculated up right now."

My current UDF is:


DEFINE_SDOF_PROPERTIES(Stein_6DOF, prop, dt, time, dtime)
{
real center;
real mass;
real force;

mass = 500.4;

prop[SDOF_MASS] = mass;
prop[SDOF_IXX] = 50.000192;
prop[SDOF_IYY] = 50.000192;
prop[SDOF_IZZ] = 50.000192;

center = DT_CG(dt)[1];
force = mass * 9.81;


if (center > 0.35)
{
printf ("\nCenter of Gravitation: %f. \n\n",center);
prop[SDOF_LOAD_F_Y] = -force;
printf ("\nForce: %f N \nCenter of Gravitation: %f.",-force,center);
}
}

This works! But its a VERY smooth (elastic) reflection.
Is there some syntax like DT_CG(dt) (which gives the position), that gives me the velocity of a rigid body?

[Deepblack]

Update:

Meanwhile, I tried to get the data at the end of the Timestep, using this UDF:

#include "udf.h"
DEFINE_EXECUTE_AT_END(save_data)
{
Domain *d;
Thread *thread;
Dynamic_Thread *dt;

d= Get_Domain(1);
thread = Lookup_Thread (d,10);
dt = THREAD_DT (thread);

printf ("Working\n");

real N3V_VEC (vel), N3V_VEC(omega), N3V_VEC(theta);
SDOF_Get_Motion(dt,vel,omega,theta);

printf ("\n\nVelocity: %f,%f\n",vel[0],vel[1]);

}


I get the output:
Velocity: 0.0000, 0.0000

It seemes that this does not work,too. Does someone have an idea?

[linh nguyen]

Tried vel = DT_VEL_CG(dt)[i]; for velocity

[Deepblack]

Thank you. I will try it.

[HyperNova]

Originally Posted by Deepblack

Thank you. I will try it.

Hello Deepblack, i hope you have managed to solve your problem. as linh suggested does vel = DT_VEL_CG(dt)[i] woks ? thank you if you answer my question

[Lucas_Gasparino]

Hey guys, similar question, but for angular velocity. I'm quite new to UDF usage, and I'm using the Interpreted command to hook it. I'm doing a small wind turbine, so I only need the angular velocity. Thanks!