Named MetaHuman Creator, the app has an interface similar to that of The Sims video game that allows users to select from a variety of preset faces.
They can then customise everything from lip protrusion to eye distance, skin complexion and teeth, creating humans with lifelike wrinkles, broken capillaries and individual bristles of stubble.
The final "digital human asset" can be downloaded and animated using the motion-capture tools within Epic Games' 3D creation platform Unreal Engine for use as a character in video games, films or other virtual productions.
"Up until now, building realistic digital humans has been an arduous process that takes weeks or months and lots of technical expertise," said Epic Games' chief technology officer Kim Libreri.
"It's a difficult, expensive endeavour that has traditionally only been attainable by blockbuster game development studios," he told Dezeen.
"When we brought the experts at 3Lateral and Cubic Motion into the Epic family, our mission from day one was to make this technology available to the world and MetaHuman Creator tool is the realisation of that vision," he continued.
"Creation time for a high-quality digital character can now be measured in minutes and hours rather than weeks or months."
Epic Games, the company behind popular online multiplayer game Fortnite, has previously worked with facial mapping startup Cubic Motion and 3Lateral to create a virtual double of Andy Serkis that recites Shakespeare and a character called Siren based on Chinese actress Bingjie Jiang.
But with the new browser-based app, Epic Games is making high-performance animation technology available to smaller, independent creators.
"MetaHuman Creator is built on decades of experience at 3Lateral and Cubic in how to recreate every nuance of a human," Libreri explained.
"It erases many laborious tasks associated with traditional CG content creation, such as modelling faces, texturing skin, adding hair and so forth."
The app lets users choose from 18 different preset body types as well as a variety of clothing options and hairstyles using Unreal Engine's photorealistic "strand-based hair system".
This information can be downloaded with varying levels of detail (LOD) via Quixel Bridge, a desktop management system for high-resolution 3D models.
So far, Epic Games has released two sample characters to allow users to experiment with the software before it is officially launched later this year.
South Korean electronics giant Samsung has previously created a series of lifelike avatars, called Neons, that are powered by artificial intelligence to act like human-shaped chatbots.
Emerging designers such as Royal College of Art graduate Marcel/a Baltarete have pushed the use of 3D scanning and animation technology towards a more therapeutic purpose, exploring how it can help those who struggle with gender dysphoria and their relationship with their own, physical body.