Nested Attributes Links on a Static Page/Profile Page

I have a nested model system and a Static Page.

My models are:

User model:

has_many :collections
has_many :designs, :through => :collections

Collection model:

belongs_to :user
has_many: designs

Designs model:

belongs_to :user
belongs_to :collection

The static page is supposed to show ALL of every users Designs, and it does. Unfortunately, the links are broken..maybe I just am doing something wrong in the controller??

Here is the static pages controller for the page that shows all of the designs:

def home
  if signed_in?
    @designs = Design.all
  end
end

I've also tried to add these line (different times) before the @designs line:

@collection = Collection.all


@collection = Collection.find(params[:collection_id])

Here is the view for the static pages (the form at least):

<% @designs.each do |design| %>
  <fields are here>
<% end %>

Why are the links broken? As mentioned, everything looks great on the page except for the links.

To show a design:

link_to collection_design_path(@collection, design)

but this turns into:

myURL/collections//designs/:id

It should look like:

myURL/collections/:id/designs/:id

The first id is the collection's id and the second id is the design's id:

The collection id is not being used in the links. Any ideas on how to fix this???