Hi all,
I've built a small piece of code that converts zmatrix in .gzmat format into topas z-matrix. This way it is possible to draw our rigid bodies in Avogadro and take advantage of all its additional features.
If u then save the molecule as gzmat u can convert it into a topas-formatted z_matrix using this python script.
https://github.com/MarcoVando/TopasAvogadroZmatrixConverter/tree/main