title: Magento - How to Add Custom Filter to Layered Navigation
body: <p>I have 3 text attributes I want to create a custom products filter based on them. The store is selling tires and we want to be able to filter by tire's size (which is those 3 attributes together)</p>
  
  <p>I already implemented the functionality and it works great BUT its core PHP  hard coded in layer/view.phtml (and another external file), now I need to take the same code but make it a custom filter integrated in Magento framework.</p>
  
  <p>I tried following this tutorial - <a href="http://www.techytalk.info/create-custom-layered-navigation-filter-magento" rel="nofollow">http://www.techytalk.info/create-custom-layered-navigation-filter-magento</a> but no lack.</p>
  
  <p>so far I created a new module but it doesn't seem to show up in the frontend (I do see it the advanced section in the backend).</p>
  
  <p>I think the main problem right now is the config.xml file:</p>
  
  <pre><code>&lt;config&gt;
  &lt;global&gt;
      &lt;models&gt;
          &lt;Companyname_Modulename&gt;
              &lt;class&gt;Companyname_Modulename_Model&lt;/class&gt;
          &lt;/Companyname_Modulename&gt;
      &lt;/models&gt;
  
      &lt;blocks&gt;
          &lt;Companyname_Modulename&gt;
              &lt;class&gt;Companyname_Modulename_Block&lt;/class&gt;
          &lt;/Companyname_Modulename&gt;
      &lt;/blocks&gt;
  
      &lt;helpers&gt;
          &lt;Companyname_Modulename&gt;
              &lt;class&gt;Companyname_Modulename_Helper&lt;/class&gt;
          &lt;/Companyname_Modulename&gt;
      &lt;/helpers&gt;
  
  &lt;/global&gt;
  </code></pre>
  
  <p></p>
  
  <p>Any insights?</p>