Enhanced 3D Display with Unreal Engine

The Unreal Engine

The integration of the Unreal engine enables very fast ray trace rendering and an improved 3D display that displays high quality shadows and reflections in real time.

Unreal is an advanced 3D engine, created to sever the needs of high quality video games, it provides a more realistic 3D display than OpenGL.

Differences between Engines

The Unreal without ray-trace have some emphasized shadows and reflections, and the Unreal with real time ray-trace (RTRT) is adding realistic shadow. From version 2026.2.1 and onwards, we can now include displacement inside the Unreal engine, which was previously only available in V-Ray. V-Ray provides high-quality shadowing, color bleed and in-depth articulation for nuances like a natural behavior of colors transmitted from one surface to another.

The following image and GIF show the differences in the multiple 3D displays.

Here is some more information about the different features we have through the Unreal Integration:

Unreal Lite (Version 2026.1 onward)

A Lightweight 3D Viewer for Lower-Spec Hardware

VStitcher now uses Unreal Engine as its primary 3D display technology. To ensure the best experience across a wide range of hardware configurations, we’ve introduced Unreal Lite — a streamlined version of the Unreal 3D viewer designed for computers with lower performance specifications. At the same time, OpenGL (Legacy) is now deprecated and will no longer be updated or maintained.

What is Unreal Lite?

Unreal Lite is a performance-optimized version of the Unreal 3D viewer inside VStitcher.

It is designed specifically for:

Computers that do not meet the full Unreal recommended hardware requirements
Machines with limited GPU memory (VRAM)
Integrated graphics cards
Older NVIDIA GTX-class GPUs
Stability-sensitive production environments

Unreal Lite delivers:

Visual quality equal to or better than OpenGL
Resource consumption comparable to OpenGL
Smooth, stable performance on lower-spec systems

It allows users to continue working in the Unreal environment without reverting to OpenGL.

Why Unreal Lite was Introduced

Previously, users working on lower-end machines often switched to OpenGL for better performance.

However, maintaining multiple rendering engines limits innovation and increases complexity. Unreal Lite was developed to:

Provide a lightweight Unreal experience
Replace OpenGL as the low-resource option
Keep all users within a unified Unreal-based ecosystem
Maintain stability in production workflows

Unreal Lite ensures that even users on minimum hardware can benefit from Unreal’s modern rendering pipeline.

How Unreal Lite Reduces Hardware Consumption

Unreal Lite achieves lower resource usage by carefully optimizing Unreal’s rendering configuration.

Key optimizations include:

Disabling heavy post-processing effects (such as motion blur, depth of field, and advanced reflections)
Reducing anti-aliasing complexity
Lowering scalability settings
Disabling or minimizing high-impact lighting features

Internal profiling shows that Unreal Lite can achieve:

VRAM usage comparable to or lower than OpenGL
Significantly reduced GPU frame time
Improved performance consistency on 4–8GB GPUs

The result is a viewer that maintains visual clarity while dramatically reducing GPU workload.

What Features are Limited in Unreal Lite

To maintain performance on lower-end systems, Unreal Lite scales down or disables certain advanced rendering features.

These may include:

Advanced post-processing effects
High-end anti-aliasing methods
Complex lighting features
Certain real-time visual enhancements

The goal is not to reduce core functionality, but to remove features that have a high performance cost and limited impact on everyday garment development workflows.

When you should use Unreal Lite

Unreal Lite is designed to run smoothly on systems that meet VStitcher’s minimum system requirements.

Unreal Lite is particularly beneficial for:

4GB–8GB VRAM GPUs
Non-RTX GPUs
Integrated graphics environments
Older workstations

For best results, we still recommend meeting or exceeding VStitcher’s recommended hardware specifications.

What this means for you

If you are working on minimum hardware:

You no longer need to switch to OpenGL
You can stay within the Unreal environment
You will benefit from improved stability and consistency
You will maintain compatibility with future VStitcher enhancements

Unreal Lite is designed to provide the right balance between performance and visual quality — ensuring a smooth 3D experience across a broader range of machines.

Real-Time Ray Trace Rendering with Unreal

The integrated Unreal engine allows fast, high quality ray trace rendering. The Real-time ray trace checkbox is enabled by default for users with a graphics card from Nvidia with RTX support. Real time ray trace rendering option is disabled for users without a graphics card from Nvidia with RTX support. For more information, refer to the Hardware for real-time rendering section at the bottom of the page.

To do ray trace rendering with Unreal:

Open VStitcher.
On the Main menu, click:
- Edit (Windows)
- VStitcher (Mac)
Click Preferences. The Preferences dialog box is displayed.
Click the Rendering tab. The rendering options are displayed:
Select which 3D display engine to use for rendering (Unreal/Unreal Lite).
- Note that Open GL does not support real time ray trace rendering.
- When you switch to the Open GL option, the Real time ray trace rendering option is disabled.
Check the Real time ray trace rendering box, then click OK. (Optional)
Restart VStitcher.

Note: Rendering a non-ray trace render image, bigger than 8k, may sometimes produce noticeable artifacts.

Changing 3D Display Mode (Version 2025.2 and newer)

The 3D Viewer now offers multiple display modes powered by Unreal Engine, giving you more flexibility for visualization, inspection, and presentation.

The following table describes your display mode options:

Wireframe	This options is useful when inspecting garment structure and geometry. Tip: If you are concerned about how your pieces are interacting after simulation, this can be useful to reference. Or if you are exporting your garment as a 3D object, this is another useful way to asses how your mesh may appear before exporting.
Solid	Simple preview without materials
Texture	Preview fabrics and textures
Final Render	Highest-quality visualization

Displacement in the Unreal/Unreal Lite 3D Display engines (2026.2.1 and newer)

Overview

You can now see displacement detail directly in the VStitcher 3D viewer, in both Standard and Lite, instead of exporting to an external renderer to check it. Displacement in the real-time viewer is turned off by default, so you switch it on when you need it.

Prerequisites

VStitcher 2026.2.1 or later
A 3D Display Engine other than OpenGL (Deprecated) — the setting is unavailable on OpenGL
A garment with displacement maps applied
Windows. MacOS support is planned for a later phase.

How to turn on real-time displacement

Open Preferences and select Rendering.
Find the 3D Display Engine section.
Select Enable Displacement in real-time 3D viewer.

The setting applies to the scene you already have open — you do not need to restart the viewer.

Note: Displacement increases GPU load and may affect performance on complex garments. If the viewer becomes slow, turn the setting off again.

Things worth knowing

The setting is off by default for every user and every file, including files that already contain displacement maps.
It is independent of the production-render displacement setting — turning one on does not turn the other on.
Your choice persists across sessions and is included when you import or export preferences.
The setting can also be read and set through the VStitcher API, with the same OpenGL restriction.
Garments without displacement maps render exactly as before.

Limitations

Real-time ray tracing and path tracing do not support this displacement method.
MacOS support for real time displacement will come at a later date.

Below is information about our depreciated 3D display engine, OpenGL:

OpenGL

OpenGL is an open source 3D engine. It provides a 3D environment that can showcase 3D objects with lighting and 3D navigation in real time. It also provides api to connect with application that needs to present 3D information.

From version 2026.1 and onward, OpenGL is now deprecated and will be phased out of VStitcher.

Unreal Lite replaces OpenGL as the lightweight 3D display option.

If you previously used OpenGL because Unreal felt too heavy or unstable on your machine, Unreal Lite is now the recommended solution.

OpenGL is supported in versions 2025.3 and lower. In the supported versions, you can switch the settings in the preferences window, in case you find the Unreal display is consuming too much memory and resulting in slow processing. Refer to Preferences to learn more.