Rahal Letterman Racing BMW M3 GT2 (workflow study)

Most people have no idea what all goes into doing a 3D model, let alone one of a well known racing vehicle. We (Russ really) decided to do a sequence of Work-In-Progress shots for this particular subject, Rahal Letterman Racing’s BMW M3 GT2.

Understand that this is not a tutorial or full detailed all-inclusive series. Think of this like the special feature of a DVD, it’s a behind the scenes look, not a filmography class.

STAGE ONE – 3D Spline Cage

This is the first stage of my 3D methodology.

While I don’t use a spline cage and patch surfacing technique to model, I do use a spine “cage” as a reference for poly-modeling. This allows me to work out my 3D proportions before building polys.

I then use these like a fully 3D blueprint to construct the body shapes. By using splines, I can create smooth flowing curves that help me position polygon vertexes accurately.

STAGE TWO – Poly Modeling

I typically start with the part I think is going to give me the biggest headache. No sense in doing everything else and then getting to the hard point and not being able to get it done. I’d rather know up front that I suck. But, when I started this project I was tired and wanted to work on easy stuff, so the biggest, simplest stuff got done first.

STAGE THREE – Poly Modeling (cont)

Like everyone else out there, I only model half of the symmetrical geometry, then apply a symmetry modifier to create the mirrored half.

STAGE FOUR – Poly Modeling (cont)

At this stage all of the “easy” body shapes are done. The remainder are filled with holes, vents, slots and screwy shapes of all sorts. The rear fender and bumper are just nuts in terms of complexity.

STAGE FIVE – Poly Modeling (cont)

At this point I have quite a bit accomplished. The remaining body panels have been completed but the front end seemed to have some bumby spots yet rendered just fine.  The front lip spoiler looked a bit too thick, so I will be tweaking that. Overall its resembling a car at this point.  In the next stage I’ll start the wheels and other details.

STAGE SIX – Wheel Modeling

Many pieces here come together to form the wheel/tire “assembly.”  Certain details on these parts are achieved with displacement maps – not modeling.  The sidewall on the tire is modeled and mapped separately from the “tread” surface. Also the the AP Racing caliper / rotor is not 100% accurate, but for all that you will see in the finished render, this will do.

STAGE SEVEN – Front Clip Details

As you can see, I try to model using separate parts whenever possible. When doing high-poly work, there’s very little incentive to model parts as a contiguous mesh. For me, having separate parts makes editing easier, materials easier and when creating things by eye, makes scaling and proportion changes easier.

STAGE EIGHT – Rear Clip Details

Again, here I am showing the benefit of using separate parts when possible. Most of the sponsor decals are NOT UVW unwrapped, but multi-sub-object material applied to select polygons with unique map channels. In the next stage, I’ll tackle the interior.

STAGE NINE – Interior Details

Interiors are where you can get away with simple model and texture work. Unless there’s a specific reason to create the extra detail, I don’t. I see long drawn out WIP projects on other fora where modelers are creating every last stitch in 3D. 3D instrument numbers and so on. Nuts. Even in close-ups, that detail is often lost. And for full car shots, most of the time, you barely see the interior. When you’re billing for your time, you don’t spend time doing things the client will never see.

STAGE TEN – Final Renders

OK!! It’s all done now. Here is the complete car in a 3D garage environment. HDRI are used for ambient lighting and reflections. There is only one light (a shadow casting spot), the rest is IBL from the HDRI. The Garage geometry has been reused from previous scenes with a few new textures to update it and make it match the car.