One of the big art tasks remaining in Wrench is modeling the Catfish and not having the game just be a grab bag of mechanical components. Modeling the body panels is fairly straight forward, I had CAD files for the bodywork which were reworked into clean topology for game use. The chassis was much more work. I didn’t have access to full cad for the tubes and essentially worked off of some drawings. From a technical perspective, tube chassis are a bit of a challenge for video game models. Tube structures have a lot of surface area which makes giving them unique texture space inefficient. Most of the detail is concentrated into the joints and the shock towers. I chose to split the model up into two materials, one for stretches of uninterrupted tube, and another for all of the joints and plate details. All of purple areas in this image got unique UV space so that I could sculpt the details in Zbrush:

The tube material has a tiling scratch map with a down vector dirt function (dirt that faces the ground). For the details material, I have a parameter to control chassis paint color and a mask to wear the paint to bare steel on high spots.

The combined result is pretty convincing. You can’t really tell that 90% of the surface is a simple tiling material and there is enough texture resolution to get good detail on the important areas.

I also modeled up the first set of wheels. I tried to keep the wheel design understated. I think this is about as simple as a 10 spoke 15×8 +35 design can get:

Lastly, I also licensed Tillett seats for Wrench. I have a Tillett B6F of my own and am excited they will be in Wrench. I’m planning to add more seat models as development continues:

Finally, here is the finished Catfish along with a few development images. I still need to add a few details like the steering column and radiator mounts, but that will wait until I have those parts built: