Question about modal analysis

[luckypants]

Dear STKO Team：

I try to build a two story frame, but there is a question about modal analysis.

The picture is the torsional modes of the two story frame, but why there isn't any modal participation mass ratio in RZ?

I think the value of modal participation mass ratio in RZ shouldn't be zero.

What is wrong with my modal analysis and my model? How could I solve the problem?

The following is my model and ModalAnalysisReport.

Any advices and helps that you provide are highly appreciated.

Best Regards

[STKO Team]

Dear User,
We will look into it. At the moment the MPM in the rotational component appears only if you apply rotational masses. We will let you know as soon as we look into this topic