Before you can use C1WebChart3D, you must add it to the Visual Studio Toolbox.
In addition to adding the C1WebChart3D control to the Toolbox, you should also decide whether you want C1WebChart3D to run from the GAC (Global Assembly Cache) or locally. If the installation program (or you) places a copy of the component in the GAC, that copy will be used by all applications that use the component. If the component is not installed in the GAC, Visual Studio will make a local copy of the required .dlls into your application's bin directory.
Using the GAC can save some disk space, but it also complicates deployment, because you will have to remember to install the components in the GAC on the server as well. In most cases, it is better to remove the component from the GAC and later use XCOPY deployment (the application folder will contain all the .dlls needed to run it). To remove the component from the GAC, open the "system\assembly" folder and delete the C1WebChart3D, C1Chart and C1Chart3D from it. For more details on the GAC, see the .NET documentation. Also, keep in mind that C1Chart and C1Chart3D have a dependency upon C1.Common.dll, and require it to run, so be sure that it is copied during deployment as well.
Note: The .NET 4.0 WebCharts do not work in Medium trust unless they are added to the GAC. Only the runtime DLL is required on the server. Putting them in the GAC requires that specific versions are used in the aspx forms and web.config files.