Hello! Today I would like to share a great way that I recently found to prototype and design vehicle tires and rims for games.
There are many ways to design a wheel using various software packages like Blender/Maya/3Dmax, Fusion 360, Photoshop photo-bashing, or even traditional methods like drawing on paper. In my opinion, I think these softwares don't provide enough freedom for iterations and are not so flexible for exploring various design forms.
Zbrush offers a unique opportunity to quickly manipulate shapes, designs, and forms, helping artists forget about technical aspects of traditional modeling such as SubD Modeling, Blueprint Drawing, or Mesh Intersection.
If you are looking to make more organic designs without limitations, Zbrush is the best option.
The most important part to remember is that your wheels add life and point of interest to your vehicle. Tires and alloys are the key areas because of their patterns, shapes, and reflective metallic colors that draw the viewer's attention.
Adding logos, brands, markings, etc., to your wheels dramatically improves the visual quality of your vehicle. Tire code should serve as a base for your wheel's details.
Detailing for Video Games.
Your wheel can be reused multiple times in different vehicles when used in video games. That means you can skip some parts of the tire code like maximum weight or pressure and make up the branding using random letters and numbers to make something similar to the serial code, something that can make sense.
Removing unique details like manufacturer name or branding helps to reuse your wheel across the game. Using unique text for a unique vehicle adds a memorizable look and epicness.
When you are really limited with the size of your texture to save video memory, and you need to overlap most of your UVW space, it's highly recommended to use something random and generic since this text will repeat itself multiple times. This technique is still going to add details to your work and improve overall quality.
Next-gen games are very realistic, but they should still make people have fun, so unless you are doing a perfect racing simulation game, tire code and patterns design functionality are less important than technical optimization and visual quality.
To start modeling our wheel template, we need to make a cylinder that can be split into 20 similar chunks. Select one of them, apply a smooth modifier on top and duplicate the same area keeping the previous selection. Use a radial array to check that all chunks match one another.
The next step is to prepare our tire code brand and manufacturer logo. It can be done using vector-based software such as Adobe Illustrator or Inkscape.
In the current example, I'm using Autodesk 3D Max for this purpose as it has powerful tools to work with shapes.
During the importing stage of your wheel parts into ZBrush, keep in mind that the .fbx format keeps the pivot world position for all objects in the place where you set them, and .obj resets all your pivots to 0.0.0. It's essential to keep your pivot at the center of your wheel because of array rotation. Before starting the array, select your tire section, and in the array menu, press the "reset" button to reset the pivot position to its origin, and after that, press "lock position."
If you are getting an uneven non-smooth surface, use polish in the deformation section to smooth your surface down. Pay attention to the circle near the polish option. If it's empty, then the polish process going to keep the borders of your mesh, and if it's full, then it will shrink your mesh borders.
Activating the wireframe and polygroups helps to see where your original section is in the 3d space.
Also, there are 2 modes of symmetry that need to be used for tire pattern design. Regular local symmetry and radial.
We are going to use regular local symmetry for drawing symmetrical sides of the wheel and break this symmetry by using radial symmetry across the wheel.
While using symmetry, keep "V.Sym" on; otherwise, you may get artifacts on your opposite symmetry side. Using radial symmetry, set its counter to 20 as we are working on the 20 sections simultaneously.
The mask drawing process takes time, especially when you are trying to keep it clean. Some tools can help you achieve this, such as mask grow, blur, sharpen, etc. Don't hesitate to use them.
To extrude your tire pattern use the inflate deformer with X and Z active. If you are going to keep Y active as well, then your extrusion is going to grow on the sides as well.
By adding volume using the Y-axis, you are achieving better transitions on the sides. Don't forget to unselect everything and return the previous size using the negative Y value for the whole wheel.
Also, check other deformers like rotate, flatten, skew, etc., to experiment with your design.
After you extrude and create the mesh from the array, all your tire pieces will be welded together. You could to dynamesh it with slightly higher values and polish your model to give some extra smoothness, and remove geometry artifacts across your mesh. To add a bit of sharpness and a crisper look, you can use "contrast" in the deformation section and "clay polish" from the geometry section.
To merge the tire with the text, dynamesh it and add some polish to create a nice and smooth transition between the tire sidewall and the text.
During the rims modeling, it's a good practice to make a central part with the correct size outside of the Zbrush, so you won't lose proportion in the process.
The whole process highly relies on the array function and its center. To achieve that, pick your middle part, insert a simple box, and while it is masked, detach it to a new subtool. Now the pivot axis of your new subtool is going to be the same as your wheel center axis.
Going into transpose mode and pressing Y hotkey, you can change the ZBrush gizmo mode. By pressing the cogwheel icon, you can open a list of mesh deformers you can interact with and modify your mesh.
These deformers list offers incredible freedom for modifying and designing shapes. This opportunity provides you with a really flexible non-destructive design workflow.
Using just a simple box object, reformers, and array, you may achieve a lot of varieties similar to these you see in the picture below.
Your model shouldn't be clean. Remember, it's just a concept, and it will be properly modeled later on.
After you have finished concepting your wheel, you can render it in Keyshot, where most of your unclean parts of the geometry will never be seen because of image resolution, lighting, and texture, or you can just make a nice simple presentation inside of Zbrush itself.
That's all for this part. If you are willing to learn more about my workflow, I will continue talking about it in Part .02. Thank you for reading!
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