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.
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
What is Unreal Lite?
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
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
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
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
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
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.
Summary
Unreal Lite is:
A lightweight Unreal configuration
Optimized for lower-spec hardware
A replacement for OpenGL (Legacy)
A step toward a unified Unreal-based VStitcher platform
If your system previously relied on OpenGL for performance reasons, Unreal Lite is now the recommended viewer mode for your workflow.
Differences between Engines
The following image and GIF show the differences in the multiple 3D displays. You can see that the OpenGL lacks shadows and there is no emphasize of layering. The Unreal without ray-trace have some emphasized shadows and reflections, and the Unreal with ray-trace is adding realistic shadow. V-Ray provides more shadows, color bleed and more articulation for nuances like a natural behavior of colors transmitted from one surface to another:
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.
VStitcher 2022.1.5 and newer
VStitcher 2022.1.5 and newer
Select which 3D display engine to use for rendering (Unreal/OpenGL).
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)
Toggle the Enable Displacement in production render checkbox to use displacement. V-ray render does not show displacement, the Enable Displacement in production render option will be disabled.
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 |
|
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.