Tuesday, March 28th, 2017 Posted by Jim Thacker

Sneak peek: Unreal Engine 4.16’s new physics tools

Epic Games has posted videos of its tech demos from GDC 2017, showing the new simulation and animation features coming up in Unreal Engine 4.16.

In the video above, senior developer relations technical artist Alan Noon runs through Unreal Engine 4.16’s clothing tools and Immediate Mode physics system, both developed for use on Paragon, Epic’s new MOBA.

New in-editor workflow for creating clothing sims
In the case of clothing, one key change in 4.16 is where cloth properties are authored.

As UE4 uses the Nvidia’s APEX Clothing technology, the setup previously had to be done within Nvidia’s standalone clothing tool, or within 3ds Max or Maya, using Nvidia’s plugins.

In Unreal Engine 4.16, cloth properties can be authored directly in the Unreal editor, reducing iteration times.

You can see the workflow from 05:15 in the video: it simply involves selected a subsection of the mesh in the viewport, designating it as clothing, and setting the low-res simulation mesh not to display in-game.

A new ClothPaint tab in the Skeletal Mesh Editor (above) enables users to paint weights onto cloth, and there are options for creating stiffness gradients between the fixed and free ends of trailing parts of clothing.

According to Noon, while the existing clothing system fails to create discernible differences between types of cloth with subtly different rigidities, “the new framework exposes a wider variety of parameters that really allow you to dial in the particular cloth type effects you want”.

Immediate Mode physics simplifies secondary animations
Another key change is the new Immediate Mode physics, which supersedes the existing AnimDynamics system used to create secondary animations for characters’ hair and trailing objects like chains or weapons.

Instead of running the simulations at world level, Immediate Mode performs a “very lightweight” local sim on each character.

The result is to reduce the complexity of the setup required for an individual character – in the demo, Noon shows a Blueprint with 37 nodes being reduced to a single node – and increase stability.

Running the simulation locally also makes it easier to troubleshoot bottlenecks in sims, and improves overall performance. “In general, we’ve found it’s a 2x speedup over AnimDynamics,” said Noon.

Pricing and availability
The new clothing simulation framework, clothing tools and Immediate Mode physics are all available in Unreal Engine 4.16, a preview build of which is available in Epic Games’ GitHub repository.

The clothing tools are officially still described as experimental, so you’ll need to enable them manually.

Unreal Engine is available for 64-bit Windows 7+, Mac OS X 10.10.5+ or Linux. Use of the editor is free, but Epic takes 5% of gross beyond the first $3,000 per quarter for any product you release commercially.

Download the preview build of Unreal Engine 4.16 from GitHub
(Requires Epic Games user account linked to GitHub)

Watch a more detailed one-hour presentation on the new physics and animation tools?