diff --git a/app/models/semester_process.rb b/app/models/semester_process.rb
index 005829560d491a24bc2fdf40839cd3119a054194..44f72a45e9d6036c8e570780828c1e1070e03891 100644
--- a/app/models/semester_process.rb
+++ b/app/models/semester_process.rb
@@ -6,6 +6,8 @@ class SemesterProcess < ApplicationRecord
     inverse_of: 'semester_process_reminder_mail_posted', optional: true
 
   has_many :semester_process_volunteers, dependent: :destroy
+  accepts_nested_attributes_for :semester_process_volunteers, allow_destroy: true
+
   has_many :volunteers, through: :semester_process_volunteers
   has_many :semester_feedbacks, through: :semester_process_volunteers
   has_many :hours, through: :semester_process_volunteers
@@ -24,4 +26,26 @@ class SemesterProcess < ApplicationRecord
 
   # will only return an array, not a AD-result
   delegate :missions, to: :semester_process_volunteers
+
+  # creates semester date range from string '[year],[semester_number]' e.g. '2018,2'
+  def semester=(semester)
+    if semester.is_a?(String)
+      super(Semester.new(*semester.split(',').map(&:to_i)).current)
+    else
+      super(semester)
+    end
+  end
+
+  def build_semester_volunteers(volunteers, selected = nil)
+    volunteers = volunteers.where(id: selected) if selected
+    semester_process_volunteers << volunteers.to_a.map do |volunteer|
+      spv = SemesterProcessVolunteer.new(volunteer: volunteer, selected: true)
+      spv.build_missions(semester)
+      spv
+    end
+  end
+
+  def build_volunteers_hours_feedbacks_and_mails
+    semester_process_volunteers.map(&:build_hours_feedbacks_and_mails)
+  end
 end
diff --git a/app/models/semester_process_volunteer.rb b/app/models/semester_process_volunteer.rb
index 523d982ea86ee1bf473469761baeacc73051c7eb..72bb1477654eae5abdb2eaef86a6020f06acd85a 100644
--- a/app/models/semester_process_volunteer.rb
+++ b/app/models/semester_process_volunteer.rb
@@ -1,6 +1,11 @@
 class SemesterProcessVolunteer < ApplicationRecord
+  attr_accessor :selected
+
   belongs_to :volunteer
   belongs_to :semester_process
+  delegate :semester, to: :semester_process
+  delegate :creator, to: :semester_process
+
   belongs_to :responsible, -> { with_deleted }, class_name: 'User',
     inverse_of: 'semester_processes', optional: true
   belongs_to :reviewed_by, -> { with_deleted }, class_name: 'User',
@@ -23,6 +28,23 @@ class SemesterProcessVolunteer < ApplicationRecord
 
   # will only return an array, not a AD-result
   def missions
-    assignments + group_assignments
+    semester_process_volunteer_missions.map(&:mission)
+  end
+
+  def build_missions(semester)
+    new_missions = volunteer.assignments.active_between(semester.begin, semester.end) +
+      volunteer.group_assignments.active_between(semester.begin, semester.end)
+
+    semester_process_volunteer_missions << new_missions.map do |mission|
+      SemesterProcessVolunteerMission.new(mission: mission)
+    end
+  end
+
+  def build_hours_feedbacks_and_mails
+    missions.each do |mission|
+      hours << mission.hours.date_between_inclusion(:meeting_date, semester.begin, semester.end)
+      semester_feedbacks << SemesterFeedback.new(mission: mission, volunteer: mission.volunteer)
+    end
+    semester_process_mails << SemesterProcessMail.new(kind: :mail, sent_by: creator)
   end
 end
diff --git a/test/models/semester_process_volunteer_test.rb b/test/models/semester_process_volunteer_test.rb
index 9243f63fcb2e650562367b36056fdd251d99490d..c3f94234806ace73d94e5e7d614dd901dd33cfc6 100644
--- a/test/models/semester_process_volunteer_test.rb
+++ b/test/models/semester_process_volunteer_test.rb
@@ -28,4 +28,60 @@ class SemesterProcessVolunteerTest < ActiveSupport::TestCase
     assert_not @subject.reload.reminders.include? mail
     assert @subject.reload.reminders.include? reminder
   end
+
+  test '#build_missions' do
+    travel_to time_z(2018, 7, 15)
+    semester = Semester.new
+    semester_process = SemesterProcess.new(semester: semester.previous, creator: create(:user))
+
+    @assignment.update(period_start: nil, period_end: nil)
+    @group_assignment.update(period_start: nil, period_end: nil)
+
+    subject = SemesterProcessVolunteer.new(semester_process: semester_process, volunteer: @volunteer)
+    subject.build_missions(semester.previous)
+    assert_equal 0, subject.semester_process_volunteer_missions.size
+
+    @assignment.update(period_start: time_z(2015, 7, 15))
+    subject = SemesterProcessVolunteer.new(semester_process: semester_process, volunteer: @volunteer)
+    subject.build_missions(semester.previous)
+    assert_equal 1, subject.semester_process_volunteer_missions.size
+
+    @group_assignment.update(period_start: time_z(2018, 7, 1))
+    subject = SemesterProcessVolunteer.new(semester_process: semester_process, volunteer: @volunteer)
+    subject.build_missions(semester.previous)
+    assert_equal 1, subject.semester_process_volunteer_missions.size
+
+    @group_assignment.update(period_start: time_z(2018, 7, 1).advance(weeks: -2))
+    subject = SemesterProcessVolunteer.new(semester_process: semester_process, volunteer: @volunteer)
+    subject.build_missions(semester.previous)
+    assert_equal 1, subject.semester_process_volunteer_missions.size
+  end
+
+  test '#build_hours_feedbacks_and_mails' do
+    travel_to time_z(2018, 7, 15)
+    semester = Semester.new
+    semester_process = SemesterProcess.new(semester: semester.previous, creator: create(:user))
+
+    @assignment.update(period_start: time_z(2018, 1, 15), period_end: nil)
+    @group_assignment.update(period_start: time_z(2018, 1, 15), period_end: nil)
+    hour_assignment = create :hour, hourable: @assignment, meeting_date: time_z(2018, 3, 15),
+      volunteer: @volunteer
+
+    subject = SemesterProcessVolunteer.new(semester_process: semester_process, volunteer: @volunteer)
+    subject.build_missions(semester.previous)
+    subject.build_hours_feedbacks_and_mails
+    assert subject.hours.include? hour_assignment
+    assert_equal @assignment, subject.semester_feedbacks.find { |fb| fb.assignment_id == @assignment.id }.mission
+
+    hour_group_assignment = create :hour, hourable: @group_assignment.group_offer,
+      meeting_date: time_z(2018, 3, 15), volunteer: @volunteer
+
+    subject = SemesterProcessVolunteer.new(semester_process: semester_process, volunteer: @volunteer)
+    subject.build_missions(semester.previous)
+    subject.build_hours_feedbacks_and_mails
+    assert subject.hours.include? hour_assignment
+    assert subject.hours.include? hour_group_assignment
+    assert_equal @assignment, subject.semester_feedbacks.find { |fb| fb.assignment_id == @assignment.id }.mission
+    assert_equal @group_assignment, subject.semester_feedbacks.find { |fb| fb.group_assignment_id == @group_assignment.id }.mission
+  end
 end