Preparing for the Interior
The inclusion of an interior for your car model can make the difference between a very realistic looking model and one that is good but not good enough. Seeing the seats and steering wheel and such through the windows of your car adds the kind of realism to a model that simple black tinted windows can't provide. Not matter how good the car model is, it will be lacking without the interior. That said, it is also prudent to realize that the creation of the interior will only make your model that much heavier on polys and your computer might complain a bit. This is why when I make an interior, I don't make it very high-poly unless I plan on doing some renders from inside the car. However, for this tutorial, we will create the interior in such a way that you can easily make it high poly if you decide you want to render the interior through use of the number of iterations on your Meshsmooth.
This part of the tutorial assumes that you have been through the earlier parts of the tutorial and that you are familiar with the techniques used because I am not going to explain things in the kind of detail that I used earlier in the tutorial.
The first step is to prepare the inside of shell of the car for the seat, steering wheel etc. The shell of your car at this point does not have a floor and you will add one. Start off by hiding all the parts of the car except one of the halves of the body. You only need on half of the body so you can easily work on the inside of the car without the other half getting in the way.
You will start with the edge of the door and construct in in such a way that you will give it a lip like a real door would have. Try and get references where the door is open so you can see what the lip looks like. With a little bit of tweaking and some edge extrudes, you should get a lip like this on the door:
Now through a series of extrusions, create the area under the front seat up to halfway point of the car as shown below.
Extrude backwards in the direction of the red arrows and then make the cut shown in green. The top polys of the car are hidden to better show the interior. Continue building backwards as indicated by the arrows and then weld the two vertices in the green circle.
Now continue building the back part of the inside and eventually you will have something like the image below. You can put as much or as little detail as you want. Make the cuts shown in red so you can add more definition to the rear seat area.
Create the red cuts and then build the polys shown in green to cover the wheel arch.
Continue building the inside of the roof of the car from the back and continue building towards the front of the car.
Continuing towards the Front
The front is done pretty much the same way you did the back. Just keep creating polys to give the car an inner shell. The dashboard of the Fiat 500 is very simple to create since it's very basic and uncluttered. Make the extrudes shown with red arrows to start the dashboard.
Do some extrusions to connect the dashboard to the floor of the car.
Now cover the front wheel arch like you did the back one. The basic interior shell of the car is now ready to be detailed and defined more. Detach all the polys of the interior shell that you just created and name them "Inner Shell" and add a Meshsmooth to them. The number of iterations depends on you and how much detail you want for the interior. Hide the rest of the car leaving just the inner shell. Now chamfer the edges around the wheel arches to define them better and then do any necessary vertex cleanup. Go through the inner shell doing chamfers to give definition to places that you think should be more defined. You can mirror an instance of the inner shell so you can get a better idea of what it looks like. At the end of it all, you should have something like this:
The interior is now ready for chairs and all the other stuff. But first you should adjust the door so that it fits better. Right now, the door looks something like the image below. This was fine if you didn't plan on doing in an interior but now that the interior must be done, it has to be tweaked to more resemble a real door on the inside. Remember that you adjusted the vertices of the door opening of the body so you must now adjust the vertices on the door to match. Unhide the body of the car and tweak the door vertices until you have a door that fits better in the opening on the body.
Continuing with the door, you should create the cushioning in the door. This is simple and all it takes is creating a box and then adjusting and Meshsmoothing it till you get this:
Now Just position it in the door. Clone it and put in the back seat area. You will need to tweak vertices to make it go around the wheel arch but you should get something like this:
Proceed to the next page for more on the interior!