Unity is a cross-platform game development engine which allows you to build anything from simple mobile apps to complex desktop games and apps as well as AR/VR games. The engine has a broad community that helps creators to learn and solve problems which arise in the process of app development.
Unity is used for scripting, scene creation, animation, app architecture development, level design, motion design, and physics implementation.
To use all the functionality of Unity, you need an asset, a 3D model. However, to build a 3D model you need to use the appropriate software.
Software for 3D modeling for Unity
There are 3 major tools on the market which you can choose from:
- 3Ds Max
All three can be used to create 3D models for Unity. The major difference between these three is that Blender is a free game development engine, 3Ds Max is a software purely used for 3D modeling, and Maya is strong in animation.
The community says that Blender is a complex engine if you’re just starting out, however it’s free so you may want to look into it.
3Ds Max and Maya may be too pricey for a beginner or if you’re a freelancer. These tools are mostly used by agencies or established 3D artists.
The process of creating a 3D model for Unity
3D modeling is the process of creating a visual and digital representation of a real or fictitious object. 3D modeling is used everywhere in cinematography, gaming, app development, architecture, automotive, healthcare, education, product configuration, sales, and presentations.
To build a 3D model one of the tools such as Blender, 3Ds Max, or Maya is used. You can create a 3D model using various methods:
- Box modeling is a 3D modeling technique where you take a simple shape like a cube, cylinder, or sphere as a starting point and work along the modeling process until the model is complete. Using simple shapes as building blocks is a good way of making your work more efficient and straightforward.
- NURBS (non-uniform rational basis spline) modeling is a mathematical modeling method that’s generating and representing curves and surfaces. The NURBS modeling technique helps 3D artists to use the so-called curve modeling. A 3D artist can draw rough lines and the software will automatically create smooth shapes. The following method can be used for quick prototyping of models by creating basic shapes of an object.
- Digital sculpting is a modeling technique where a 3D artist uses a digital brush to manipulate a 3D object. The process is similar to using clay in real life. But in this case, an artist is using a software editor to work with a digital object. The method allows models to be built extremely quickly, however, it also makes models very polygon-intensive and heavy so that further optimization is required.
- Procedural modeling is a method of modeling where a 3D artist is using mathematical formulas, algorithms, and sets of rules to build 3D models or environments. Procedural modeling is used with randomized object details such as trees, landscapes, mountains, fire, water, and other substances.
- Image-based modeling or photogrammetry is a new way of modeling which is based on rendering models from images. An expert takes 360° photos of an object, then uploads them into the software which generates a model. The software creates a 3D model based on the imagery. The cleaner the shots the cleaner the model is. Often, the model requires further manipulations and retopology to make it visually appealing, smooth, and comfortable to work with.
Retopology is the process of converting high-poly models into low-poly ones. This step is an integral part of the post-modeling process that helps make models easy to work with in Unity.
Retopology helps to reduce the polygon count to optimize a model for mobile games, apps, PC games, or AR/VR apps.
An artist can either manually create a new mesh over the existing model or use automatic or semi-automatic retopology tools such as Maya, ZBrush, or 3D-Coat.
UV mapping is the process of projecting a 2D image to a 3D model’s surface for texturing. In other words, an artist takes a 3D model, unfolds it, and creates a 2D image which is easier to paint textures upon.
UV unwrapping is done before you apply an image texture to a model to tell the software the position, rotation, and scale of a texture. The UV mapping can be generated manually or automatically depending on the complexity of a model as well as the skills of the artist.
The most popular UV mapping softwares are Roadkill, Ultimate Unwrap 3D, and the in-built UV mapping functionality in Blender or Maya.
Rigging is a 3D modeling method of adding bones to a 3D character or an object for creating flexible and movable parts for animation.
The rigging method is used everywhere from animating a face of a character to the opening doors of a car. By creating a digital skeleton structure of an object, you can easily manipulate it for creating a pose of a shot, making an animated movie, or using it to create an animated character in a game.
However, the digital skeleton will not be moving with the “meat” unless you actually bind it to the mesh you’ve created. This requires a method called skinning.
Skinning binds the 3D mesh with the bones (rigging) so that you can move vertices and use your model to the fullest capacity in animation.
Proper skinning is important because it helps to create smooth animation and makes sure your legs are not dragging behind when you manipulate the eyes of a character, for example.
Skinning ensures the right deformation of a model. The skinning can be done manually or automatically using various functions such as Smooth Bind in Maya.
Texturing is the final stage of the modeling process. To achieve the best texturing results using with materials and textures an artist has to make sure that the model has been rigged, skinned, retopologized and UV mapped successfully.
There are different types of texturing methods such multi-texturing, mipmaps, height mapping, bump mapping, normal mapping, displacement mapping, reflection mapping, specular mapping, and occlusion mapping which can be used to create stunning photorealistic or cartoonish graphics you see in apps and games today.
Texturing is usually done in Substance Painter, BodyPaint 3D, Zbrush, Mudbox, 3D-Coat or other software which allows artists to achieve realistic looking and cool model textures.
How to work with models in Unity
Despite the fact that you can now be 3D modeling in Unity using ProBuilder, it’s still better to use the appropriate software which allows for more flexibility and complex modeling. It may not be as necessary at the start, but as you advance it’s great to be already familiar with the professional software.
Anyway, let’s jump into working with models in Unity. By the way, you can find the full guide on how to work with models in Unity manuals. The support of the community and full documentation is the only recipe for success in modeling.
Importing assets from a 3D modeling software
Importing assets into Unity is simpler than it seems. Just create a folder in Unity editor and drag the required assets in it. After that, you can start working with assets in Unity and do things like:
- Use Mesh Compression, Optimize Mesh, Keep Quads, Index Format, Weld Vertices to reduce the resources and save memory which is perfect for mobile and desktop apps
- Use Preserve Hierarchy to save your animation properties of a model
- Import materials and textures
- Work with full 3D, orthographic 3D scenes or 2D with 3D graphics
- Work with full 3D, orthographic 3D scenes or 2D with 3D graphics
- xBuild UI and app hierarchy
Unity allows you to work with models in various ways and achieve great results using in-built functionality in the hands of a skilled Unity Developer and a 3D artist.