As already mentioned, we have at least three options to have materials in Lumion. The first option is the one we just saw: using Lumion's materials. In most cases, the materials available will be enough for your project, but there are always special requests from the client to use a particular material and that leads us to the second and third options.
The second option is to use the imported materials that you create in your favorite modeling application. This makes a lot of sense, because if you are modeling, it's always a good idea to do the following:
Do a quick render to check how the geometry is looking and whether there is a need for more work in certain areas. It also helps to see where you can have better highlights.
Assign a texture to the surface and see how the model and the texture combine and if there is a need for minor adjustments.
Then you can easily export everything using FBX or COLLADA, because...