Dear all,

I am using FAST 7 with the following manual nwtc.nrel.gov/system/files/FAST.pdf.

I would like to get out the state of the blade segment, such as acceleration, velocity, orientation and deflection. In the documentation I found only the option to get out the blade segment acceleration. By checking the FAST source code I found some other options:

```
"Spn1TDxb1, Spn1TDyb1, Spn1TDzb1" - Blade ???
"Spn1RDxb1, Spn1RDyb1, Spn1RDzb1" - Blade ???
```

I would guess this are the translation and rotation of the segment. However I am not sure how is it defined.

I have several questions:

- Is Spn1TDxb1 the translation along the x-axis and Spn1RDxb1 the rotation around the x-axis?
- Are these parameters defined in the blade coordinate system?
- Is it possible to get out the segment velocity as well?
- Is it possible to get the values in the tower bottom or global coordinate system?

There are several coordinate systems, is it possible to get out the rotation and translation matrices for each coordinate system with respect of the previous coordinate system?

Thank you for your help in advance.

Regards,

Robert