As with all character modelling I began with the head, The majority of the character was made up of basic shapes to depict his cobbled together appearance so was very straightforward, I just kept referring to my rough turnaround I did of this characters head and adapted it to look better where necessary.
Making the head look functional, weather or not I would decide to animate it at a later stage was important to emphasize his personality, so areas like around his jaw, the rubber covering on his neck and his eyebrows I modeled with this in mind.
I was keen to emphasize the lack of symmetry in Sprockets design, as he is a bipedal character to start with, to make him more interesting to look at. This however meant relying on the symmetry modifier to do most of the work wasn't an option, and so each separate element of the model had to be constructed individually (with the exception of the occasional cylinder here and there).
I Made the effort to keep in mind how the model would work when rigged, and so I paid attention to joints and how they would move and interact with the rest of the body. As I tend to sketch things out how they look good and functional in one position I had to adapt things slightly so they would not look odd when for example, the forearm bends at the elbow. Moving the arms at the shoulder down to the waist also gave me a good inclination of scale and made me aware if i was making the arms too long or short.
There is a lot of exposed cables and tubing on this character's design from his head to his feet. As opposed to making a couple of different types then just copying them all over, I modeled them all from scratch for the authentic look for the snaking cables. Seeing them snake between body parts and hanging out of various bits gives the silhouette a much more interesting look I feel.
This is just a fun pose I did during the modelling phase; To make sure both the limbs work with the body when put in situation more than anything, and to make sure there is not weird meshes overlapping in obvious ways. Sprocket's left arm isn't symmetrical with his right, so again I had to construct a lot of its elements from scratch. The hand is mostly copied over as it was largely the same design. I just tweaked the scale of the palm to suit the large forearm it was attached to.
The legs are probably the trickiest part: They're the most openly damaged and cobbled together part of sprocket, with lots of exposed mechanisms and wiring around his broken Armour plating. Once the tricky shaped plating was created, it was just a case of positioning all of the components within in the most efficient way. I mostly used cylinders and other basic shapes apart from areas that were more obvious such as the knee joints, to be the pistons and other parts.
Though I could utilize a lot of the same elements within each leg. the main thigh plating was unique on each side so had to spend a lot of time making this area truthful to my original sketches and artwork. Some areas though, like the shine plate, I was able to use in both legs but adjust slightly so they both bore the same shape but were still distinguishable and separate from one another.
The final base mesh: Very pleased with how sprocket has turned out! due to the time I spent on even the smallest details he remains true to the original artwork in every way, the only changes I made were so he adapted better to his 3D form. The most important thing though is with his face he maintains his sort of baffled but curious expression that was really important in carrying over to his model.