Prototyping with 3D Primitives

Justin Horner
2 min readSep 14


Stages of prototyping before using custom assets

Preproduction in game development typically starts with an idea that could be a good mechanical hook that needs to be prototyped to find out if the idea is actually fun once implemented. At this stage, we want to be able to move as quickly as possible as we work with designers to tune the idea. Unfortunately, we sometimes find that the game idea just isn’t fun enough to pursue.

Objective: Let’s talk about the benefit of prototyping without custom assets and some options to use for visuals to save the team time during preproduction.

We want to keep the worst-case scenario in mind when it comes to time and money spent in preproduction. If a small group of programmers and a designer can work through a prototype then the time and money lost if the idea doesn’t make it to production is reduced substantially. Here are some ways we can go about prototyping visuals quickly.

Unity ProBuilder

If you need to prototype levels, I highly recommend ProBuilder, which is now part of Unity. It enables you to quickly prototype structures, terrain features, weapons, and much more. It supports integrations to add more detail and polish later. You can learn more about it here.

Key Features of ProBuilder from Website

3D Primitives

The approach I often use is to create 3D primitives, even for what will ultimately be a 2D game. With this approach I can quickly create new Game Objects with Meshes for Cubes, Spheres, Capsules, and Cylinders that I can then differentiate using their scale and create materials to change colors.

Switching to 2D later is a simple process of switching to sprite renderer and making adjustments to collision/trigger methods and colliders. Some of the manual steps could be automated with an Editor tool, but in my case the prototypes are small enough in scope that this is not a huge effort to do manually.

Asset Store Placeholders

Another approach that I sometimes use is finding placeholder art from the Unity Asset Store. This usually works out pretty well, but I find that I prefer not having a visual reference at all in the early stages. It’s easy to get too attached to the placeholder art or limited by it and end up spending time adding to complete it.

I compare it to putting too much information into the early stages of a web/mobile app wireframe. We wouldn’t want a lot of information about color palette or typography when our focus is the content structure. Once we know what we’re building, we can then put more resources to defining the branding, colors, typography, etc.


I hope you found this guide helpful. What approaches do you use for prototyping to balance staying focused on the mechanics while also giving enough visual feedback for yourself and designers?

Take care.
Stay awesome.



Justin Horner

Software Engineer at Meta, Supernatural