Some of you may have completed adding your custom subassemblies onto your tool palette already so; in that case you may skip this post. But in case there are some users others out there wanting to do it and are wondering how - this may be an article for you.
Before I start I’m going to fast forward assuming that you have all your subassemblies created, with images and all that. It is worth mentioning the default location for Tool Palettes (C:\ProgramData\Autodesk\C3D 2013\enu\), although you may have it set differently. Here is how to add custom subassemblies that you may have received from your contractor, development or you created it by using Autodesk Subassembly Composer.
1. Launch Civil 3D 2013
2. In command line type CONTENTBROWSER to get into Content Browser
3. Drag and drop your custom ATC file named (I named mine Test.atc) to the Catalog. If everything is correct with your subassemblies you should get something like this:
4. Click to open the Test Subassemblies we just imported catalog to find the assemblies and subassemblies in it
5. Now, back in your drawing, open your Tool Palette and right-click on it
6. Choose new Palette and name it (I named mine Custom)
7. Drag and drop the subassemblies from Content Browser to Civil 3D Tool Palette to use them in design. Make sure you click on the icon until you see a pencil showing. Then you can just drag and drop it onto your new tool palette
8. Once you have it on the palette you can just use it as any other subassembly or block.