You can import and work with 3ds Max graphics (.3ds) in Poser 3D character art tool and produce a broad range of formats, including .pmd morph files. As far as we know, this particular conversion between 3ds Max and Poser file types is only doable with Poser and no 3rd party all will help you here.
Convert 3ds Max (3D Studio MAX) graphics to Poser morph file.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert 3ds to pmd on Windows
Program for making 3D character arts and animations
Convert from 3ds file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.