Automatic geomTransf vecxz

[NetoConrado]

Hello! I am wondering if anyone knows any tool to calculate the vecxz for the geomTransf command.

I am modelling a large 3D bridge with frame elements (not truss) and I need to automate the calculation of vecxz for all the elements with different inclinations/angles.

I just need the local z to be in the vertical direction (pointing up) and y pointing to the left.

I am also curious as to why Opensees has to automatic (or default) option for this vector. In SAP2000 the local axis are defined automatically, isn't it? why OpenSees doesn't simplify this? it is an honest question, I assume there is a good reason for it and I want to know

thanks a lot for any ideas/suggestions!

[mhscott]

You can do what's described in this post: http://portwooddigital.com/2020/08/08/a ... x-z-plane/

Python is shown in the post, but you can do the same thing with Tcl.

[NetoConrado]

You can do what's described in this post: http://portwooddigital.com/2020/08/08/a ... x-z-plane/

Python is shown in the post, but you can do the same thing with Tcl.

Thanks, Scott. This helps a lot
I used that algorithm and I have one quick question
if the element direction coincides with the global Y, then the vecxz returns 0 0 0
is that correct?

[mhscott]

Yes, you have to use a different vector for elements that coincide with global vertical

[NetoConrado]

Yes, you have to use a different vector for elements that coincide with global vertical

Oh I see. I need to carefully define how I want those to be myself
thanks