# Change the position of the axis of a segment

Hi,

I wanna know if it is possibly to change the position the origin of the axes of a segment for refer the nodes to those axis. For example that could put the origin at the end of the segment.

Hi Lincoln,

It is possible to change nodes and axes, but I do not understand what you plan to do.

What I´m trying to said is, that instead of having the axes (the local axes of a segment) in the center of gravity. May i put it for example, at the end of the segment for that way i can put the coordinates of a node (AnyRefNode) since that position.
Because when you create a AnySeg it have already an axes but it put in the center of gravity, but what i want is to change it and move to one end of the body.

Hi,

We dont really get what you want to do. You could keep the CoM in the origin and define your nodes relative to that. If you are afraid that the output will use this origin later - you could always change your output reference frame and there will be no problem. So this is just a selection of the reference frame. You could also make a nested configuration - you have a node on the segment, which defines your local reference frame and everything else belongs to this node.

But please try to explain or possibly draw what kind of problem you have.

Regards,

Pavel

Well i coud try to explain one more time:

`````` AnySeg Arm={
r0={0,0,0};
Axes0 = {{1,0,0},{0,1,0},{0,0,1}};
Mass= 1;
Jii = {0.27722, 0.01, 0.27722}/15;

AnyRefNode M11 = {
sRel = {0.0421,-0.0020,0};
};
``````

};

That point (0.0421, -0.0020, 0) are refering on the axes of the segment where are putting the node, BUT those axes are on the gravity center of the segment. the question that I´m asking is that if it is possibly to change the position of the axes thus able to change the coordinates of the node, putting my frame of reference at the end of the segment.

Best regards,
Lincoln

Hi Lincoln,

Please see the code below i have changed the CoM of the segment to have its position at the negative sRel value you provided on node M11.

Then the sRel of node M11 is Zero. This configuration should be working in the same way as your description but the origin of the seg is different…

Best regards
Søren

``````
AnySeg Arm={
sCoM =-{0.0421,-0.0020,0};
r0=-{0.0421,-0.0020,0};
Axes0 = {{1,0,0},{0,1,0},{0,0,1}};
Mass= 1;
Jii = {0.27722, 0.01, 0.27722}/15;

AnyRefNode M11 = {
sRel = {0,0,0};
};

};

``````