Pre-production involves finding references or source material for the specific thing that you are modeling. If it is a realistic, real-life object, then images of the object, or even schematics, are appropriate. Otherwise, if it is original (e.g a character, monster, etc), it would be more useful find reference images that are similar and then use them to create concept art.
^Schematic/Blueprint of a ship. Retrieved from Anatoliy Nepochatov.
^Sometimes, an image search is all you need
The purpose of this stage is to provide a foothold/starting point from which to begin 3D modeling. In some situations, the concept art may be directly imported into the 3D modeling software. This allows the modeler to directly follow the contours of the concept art.
This stage is all about creating a usable asset. There are many programs that can help achieve this, such as 3dsMax, Maya, zBrush, Mudbox and more. They are all a little different but the core principles behind them are all the same.
^Overview of modeling basics.
All of the programs rely on multiple vertices that form polygons or quads. By adding and arranging these vertices, it creates a mesh which is our object. It is a modelers job to manipulate the vertices and faces in order to achieve the desired outcome.
^A completed model of a radio.
The number of polygons that are in a model determine its ‘quality’. It is entirely dependant on the restrictions of the target device that the model is being made for, but there are typically two different qualities. They are low-poly and high-poly. This simply refers to the number of polygons that a model is made of.
Finally, the structure and distribution of polygons. This is referred to as a models topology. On non-static models, e.g characters with animation, it is important that joints that move have a higher poly count so that movement looks smoother.
UV Mapping is the process of ‘peeling’ the ‘skin’ off of the model and flattening it into a 2D image.
The left section of the above image is the UV. It shows every face of the model but on a flat plane. This collection of faces is referred to as a UV Shell. By texturing the image beneath the UV Shell, the image is projected onto the faces of the 3D model.
As you can see on the image above, the colours and patterns that are on the 3D model can be seen on the corresponding UV Map. The UV Map on the right is made of a variety of shells all unwrap from the 3D model.
Nepochatov, Anatoliy. (3 May, 2017). Wargaming’s 3D Modeling Workflow. Retrieved from https://80.lv/articles/wargamings-3d-modeling-workflow/
Pettit, Nick. Asset Workflow for Game Art: 3D Modeling. Retrieved from http://blog.teamtreehouse.com/asset-workflow-game-art-3d-modeling
Terävä, Tapio. (2017). Workflows for Creating 3D Game Characters. Retrieved from http://www.theseus.fi/bitstream/handle/10024/131241/Terava_Tapio.pdf?sequence=1&isAllowed=y