In HyperMesh Post, if you want to easily and quickly import combined load cases, you can do it importing a specific .csv file.
This article will explain the formalism of this file and how you can import it.
The formalism for Linear Combination : 
For Envelope, the formalism is basically the same, the diffence is in the name of the column where you defined the new loadcases, see below in Excel and in a text editor:
In HM Post, it is not possible for the moment to import Step loadcaes.
In the attached video you can see the different steps :
- Create the .csv file with the new loadcases
- Open the model
- Import results : File > Import > Result > BatchImport (.csv)
- Combinations will be visible in your browse, and you can use them for post-process.
