<%= f.text_field :height_ft %>
<%= f.text_field :height_in %>

attr_accessor :height_ft
attr_accessor :height_in

............

def before_save
  @height = @height_ft *  12  + @height_in
 end 

NoMethodError in MyuserController#create

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.*

app/models/myuser.rb:112:in `before_save'
app/controllers/myusers_controller.rb:18:in `create'

Request

Parameters:

{"utf8"=>"✓",
"myuser"=>{"login"=>"fnfnfnfnn",
............
 "dob(2i)"=>"11",
 "dob(3i)"=>"8",
 "dob(1i)"=>"2010",
............
 "height_ft"=>"5",
 "height_in"=>"3",
............
 "weight"=>"30"},
 "commit"=>"Get strted!"}