"Work hours" for each resource (like for calendar)

" When you display work for all project in days, how is done conversion from hours to days for all resources ?"

"For instance, define work period of 8 hours a day.
Resource working 7 hours a day have capacity of 0,75.
Resource working 9 hours a day have capacity of 1,25, and a specific calendar with only 4 working days per week. "

==> it makes same thing than you propose to me
I've 1.25 days / day

thanks for your help, your solution works perfectly !