# Selection of coordinate system for node translation

Dear all

I have a general question:
How do I select a coordinate system for a translation of a node?

I am interested in the rotated coordinate system of another node which I have previously defined, however, it always picks the std coordinate system orientation. Besides the example below I have also tried:
sRel=.GHReactionCenterNodeRotated1.sRel+{0,-0.015,0}*.GHReactionCenterNodeRotated1.ARel;
but also there I don't get a translation in the desired y-direction only.

Thank you for your help!
Best,
Johanna

``````    AnyRefNode    GHReactionCenterNodeRotated1 = {

sRel=.GHReactionCenterNode.sRel;

AnyDrawRefFrame drw={ScaleXYZ={0.05,0.05,0.05};};
AnyDrawNode drw2 = {ScaleXYZ={0.001,0.001,0.001}*2;};

//Calculate rot matrix for cylinder using three points
AnyMat33  Mat = RotMat(sRel,.EdgeNode1.sRel,.EdgeNode2.sRel);
ARel= Mat;
};

//achieve rotation of glenoid around point on inferior glenoid rim
AnyRefNode    GHReactionTestNode = {

//sRel=.GHReactionCenterNode.sRel;
// JO: change location of rotated node
sRel=.GHReactionCenterNodeRotated1.sRel+{0,0.03,0}*.GHReactionCenterNodeRotated1.ARel;

AnyDrawRefFrame drw={RGB = {1,0,0}; ScaleXYZ={0.05,0.05,0.05};};
AnyDrawNode drw2 = {RGB = {1,0,0}; ScaleXYZ={0.001,0.001,0.001}*2;};

//Johanna: glenoid inclination -  using axis and angle
AnyMat33 Mat2 = RotMat(30*pi/180, x);
ARel=.GHReactionCenterNodeRotated1.ARel*Mat2;
};
``````

Hi Johanna,

I have tried your model and read the question a couple of times, but i am not 100% sure i understand what you are trying to achieve.

The model will move the node along the local y axis. and it will pick is orientation from the other node and rotate it 30 deg on x local axis.

Please provide some more details on what it is you need, i am pretty sure it is possible to do

Best regards
Søren

Dear Søren

Thank you for your reply!
I hope the image on the right is illustrating what is happening and what I want to achieve
The green coordinate system is the initial orientation of the GHReactionCenterNodeRotated1 and the yellow one after the rotation according to the rotation matrix "Mat".
I would like to translate the red node ( GHReactionTestNode) along the yellow coordinate system and not along the green one.

Thank you and best regards
Johanna

PS: the image is based on the following defintion of the GHReaction Test Node

``````//achieve rotation of glenoid around point on inferior glenoid rim
AnyRefNode    GHReactionTestNode = {

//sRel=.GHReactionCenterNode.sRel;
// JO: change location of rotated node
sRel=.GHReactionCenterNodeRotated1.sRel+{0,0.03,0};

AnyDrawRefFrame drw={RGB = {1,0,0}; ScaleXYZ={0.05,0.05,0.05};};
AnyDrawNode drw2 = {RGB = {1,0,0}; ScaleXYZ={0.001,0.001,0.001}*2;};

//Johanna: glenoid inclination -  using axis and angle
AnyMat33 Mat2 = RotMat(30*pi/180, x);
ARel=.GHReactionCenterNodeRotated1.ARel*Mat2;
};``````

Hi Johanna,

Please this sample code

``````Main ={
AnyFixedRefFrame GlobalRef ={
AnyRefNode    Node1 = {
sRel={0,0,0};
AnyDrawRefFrame drw={ScaleXYZ={0.05,0.05,0.05}; RGB = {0,1,0};};
//random rot
AnyMat33  Mat = RotMat(0.2*pi,x)*RotMat(0.2*pi,y)*RotMat(0.2*pi,z);
ARel= Mat;
};

AnyRefNode    RotatedNode= {
AnyDrawRefFrame drw={RGB = {1,0,0}; ScaleXYZ={0.05,0.05,0.05};};

AnyMat33 Mat2 = RotMat(30*pi/180, y)*RotMat(30*pi/180, x)*RotMat(30*pi/180, z);
ARel=.Node1.ARel*Mat2;

AnyRefNode    Translation = {
sRel = {0,0.05,0};
AnyDrawRefFrame drw={RGB = {1,0,1}; ScaleXYZ={0.05,0.05,0.05};};
};
};
};
};

``````

I am using a node inside the rotated node, this is the easiest way.

Best regards
Søren

Thank you Søren

Your example helped me understanding how node rotations and translations work!

Best,
Johanna

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