Part Creation

Common Mistakes

These are the mistakes we see most people make:

• Not curving your A pillars
• The window is too curved to actually roll down into the door
• Body panels being too flat, generally, every panel has some type of curve in multiple directions (of course there are some real world exceptions)
• Scale being off (please find dimensions of the bigger parts such as engines, axles, seats etc.)
• Bolts being over 6 polygons
• Bad driver ergonomics (use a correctly scaled human 3D model, it helps a lot)

Design Philosophy  

Our vehicles have a very high level of mechanical detail and accuracy in the chassis and powertrain.

The mechanical models are usually started by comparing a couple of examples of the same object in real life. If tasked to build a modern V8 powered sedan one should find reference images of different v8s in comparable cars, and use that to build a unique design.

Major components should have details that reflect the mechanical function of the part, but not too much clutter. For example, engine spark plug wires are a good detail because they are recognizable, but various small hoses snaking around the carburetor? not so much, they don’t have have recognizable purpose.

To do this well requires some understanding of what the components are and what they do.

Brakes

We use existing shared meshes for the disc brakes, unless the vehicle is very atypical (heavy truck, ATV, or something like that).

If its a drum type, the drum and backing plate should be separate, with the ability for the drum to separate from the backing plate without missing faces.

Disc brakes should have a separate disc and caliper. Ideally the spindle will have some geometry to meet the caliper so that it does not appear to float. The disc brake can be broken off in game, so the spindle must not have missing faces behind the disc.

Roll Cage Design

Rules for cages:
(note that I’m not an engineer, so don’t build a real cage using this)

• Tubes should terminate near intersections
• Triangulate when you can, it is the strongest shape

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Cage Design

Because the forces go to the unsupported part of the tube. Causing the tube to bend. Also the door bars are separated from each other. The further apart they are the less they reinforce each other.

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The forces will travel to tube intersections, the strongest points of the cage. The forces will travel directly into multiple tubes. The door bars are as close as possible so they reinforce each other.

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Seat Belt Mounts

Every cage needs seat belt mounts.

There will always be a crossbar that you can wrap the belts around (selected bar).

Roll cage body tie points should always attach on or near the strongest points of the car.

If it’s a body over frame:

• The cage will go through the floor and attach right to the frame

If it’s a unibody:

• Roll cage should attach near strong points
• Below the A pillar and B pillar
• The cage should be welded to a 16cmx16cm plate minimum
• Then that plate is welded to the unibody to distribute the forces
• The rear cage tie points should attach near the rear strut mounts for rigidity

Engines

Engines should have correct overall dimensions, with the number of cylinders noticeable by the number of exhaust ports.

Take care to understand the internal design to guide modeling. It’s the same principle as using anatomy to guide a sketch of a person.

It should make sense to someone who knows how to replace a radiator in a real life vehicle.

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Engine Components

Engine components that should be represented:

• Engine block and head
• Oil pan
• Exhaust manifold
• Starter motor
• Alternator
• Belt system, including:
  • Crankshaft pulley
  • Alternator pulley
  • Idlers
  • Possibly others (power steering pump, water pump)
  • Pulleys should be separate meshes set up as props for animation
• Radiator fan (electric mounted to radiator or a mechanical fan mounted to the engine depending on references)
  • Should be separate meshes set up as props for animation
• Ignition wires (if visually prominent)
• Radiator and hoses
• Intake manifold and intake device (throttle, carburetor), air filter
• Turbocharger (with correct shape and piping)
• Supercharger (with added belt drive from crankshaft pulley)

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Engine Bay

Some additional components should fill the engine bay, depending on what is visually prominent in the references (please reference the latest in-game vehicles for the amount of detail to add).

• Battery
• Brake master cylinder and booster (on the firewall)
• If there are some prominent items such as fluid bottles or fuse boxes, they could be added to fill in the engine bay a bit. Try not to make “random boxes and wires.”
• Plastic engine covers

Separable Parts

Examples of common separable parts:

• Hood
• Doors
• Bumpers
• Trunk/rear tailgate
• Engine and Transmission together
• Drive shafts
• A-Arms
• Axles
• Body
• Chassis
• Accessories (roof lights, cargo boxes, rock sliders, side steps, etc.)
• Headlights
• Grille
• Taillights