gistfile1.rb

def new
  @product_request = ProductRequest.new
  @ps = ProductSpecification.find(params[:spec])
  @product_request.height = @ps.height
  @product_request.width = @ps.width

  respond_to do |format|
    format.html # new.html.erb
    format.xml  { render :xml => @product_request }
  end
end