The main idea was to have armor with a kind of edgy backbone to shape the silhouette in a certain way. Here and there during the making of the anatomy, I opened my sketch book and drew some little sketches and silhouettes of what the armor could look like. When I was satisfied with the silhouette, I drew a really rough model sheet (Fig04). You can see that I conceptualized the syringe-rail-gun but never had the chance to model it unfortunately!
Because I work better in 3D than in 2D, I decided to make the biggest part of the conception in Max and ZBrush instead of Photoshop or my sketchpad. In ZBrush, I decimated the anatomy with Decimation Master and imported the OBJ file in 3ds Max. In Max, I modeled over the anatomy a basic mesh for blocking the shapes of the armor while helping myself with the model sheets (Fig.05).
I didn't care how the topology of the armor mesh looked like at that point since it was only to evaluate the overall silhouette of the character. Then I imported the mesh in ZBrush to continue the concept in finer details with the tools given. In ZBrush, if I wanted to add another module or shape, I just added a new primitive like a cube or a sphere instead of going back in 3ds Max and re-exporting another object.
Once I was satisfied with the complete armor concept, I decimated what I'd made in ZBrush, imported it in Max, put a semi-transparent material on it (like the X-ray mode) and built the highres armor over it.
I used basic techniques to build the highres mesh of the armor, but I didn't use the basemesh since it didn't have the topology I needed. I created a new plane and started extruding it until I had a solid basemesh. Then I activated the NURMS subdivision in "subdivision surface" to see what the model would look like in highres and I added edges and edge loops to make the highres result look sharp with nice fillets and chamfers (Fig.06). When doing small details, I tried using Bevel, Inset and other tools, instead of doing manual maneuvers, in order to keep the hardness and flow of the shapes.
Once the highres armor and the ZBrushed anatomy was finished, I used "Max retopo" (a free 3ds Max plug-in that snap the vertices of an object onto another object) to make the final lowres mesh. This is where I started counting the polys to make sure I could fit in the targeted budget of 10-15k.
Note: I didn't know about this software at that time, but now I strongly recommend trying Topogun for retopology!
You must never underestimate the power of the normal maps! While doing retopology, it's important to make some tests. Model complex and simple lowres meshes and bake them with the same highres model and you'll be surprised how much the normal map doesn't need to have a lot of poly to look good! The goal of the retopo should be to make sure the silhouette of the lowres model stays accurate with the highres model and let the normal map fake the details and the roundness of the shapes within the polys.
When I was finished with the retopo, my character was in many separate pieces: the hands, arms, backbone, helmet, legs, both legs joints, feet and anatomy were all different objects. I didn't attach them until I was done with the normal map baking process.
In Fig.06a you can see the complete highres armor rendered with a simple occlusion on the left and the wireframe/mesh of the final lowres model (12 100 polys) on the right.