I usually turn in something like this to get started, a very rough block-in, sometimes with color, sometimes just gray - depending on how I created the colors for the vehicles. Once it's approved, or with adjustments made, I get going on the final.
And here is the final turnaround for this bad boy. The design conceit for these Combaticons was to keep them sharp, but with flat planes to mimic modern military design. Over the last few years I've built up a library of car parts, from the web, car shows, and my own cars, to use to fill gaps, or start a bigger mechanical design from something real.
The front view takes on average around 12-14 hours to complete, including the block-ins, the back view takes around 11, because the silhouette is defined. I just import the outline and fill it in with rear view elements., making adjustments as needed. And yes, technically, his butt can light up.
The side view takes up to 2 days to finish, because of the additional elements that need to be shown; torso, arm, insides of legs, and any additional weapons. And I can't use the best cheat of all, copying one half and flipping it, like I do for the symmetrical parts of the front and back views.
So that's it for the Combaticon Scout - a full set of concepts, final vehicle views, and final robot views, that takes about two weeks altogether on average.
Tomorrow - Combaticon Warrior!