## 4 Discussion
### Comparison with Existing Tools  
The aforementioned advantages of the visual editor with live preview, compared to writing code, make the haptic feedback design tool more convenient than the basic vibration control functions built into Unity [50] and Godot (version 4.4.1) [51] engines. In their original form, and without the use of additional paid third-party assets, these engines lack the functionality for visualization, visual creation, and live preview of haptic effects. Unreal Engine (version 5.5) natively offers the most comprehensive and advanced built-in system for implementing gamepad vibration among all game engines. According to its documentation [52], an arbitrary number of channels can be created when designing a haptic effect asset, with each channel capable of playing a different effect defined by a curve and assigned to specific vibration motors. These effects can be played on a specific device either once or in a loop, stopped, and dynamically added to any actor during live gameplay. Per-device overrides are supported, allowing different feedback configurations for each platform. Additionally, effects can be reproduced from a specific source within the game world, with their intensity varying based on the distance between the source and the player. However, it is not possible to freely define the distance-to-intensity curve for these effects. Unreal Engine includes an experimental feature for audio-based vibration, which is currently only supported on the Sony PS5 DualSense controller. The current version of the tool proposed in this paper does not support the creation of haptic feedback channels in the same way as Unreal Engine, but it does allow for the simultaneous playback of multiple haptic effects, automatically layering and blending them based on their properties. Furthermore, while it does not include a per-device override system identical to that of Unreal Engine, similar functionality can be achieved by duplicating an effect and modifying the copy to suit a specific platform. These are features that will be given further attention in future versions of the tool. Although Unreal Engine provides a visual editor for haptic effects with a preview feature, it lacks a visual representation of the effect during preview, unless a specific effect is opened in the Force Feedback Effect editor [52]. Additionally, there is no playhead to track the preview progress, no option to loop the preview, and users cannot toggle the different components of the haptic effect individually during the preview. Furthermore, there is no option to select one or more specific devices for the preview (Figure 14c). Meta Haptics Studio (version 1.3.3) [53] enables the design of haptic effects that can be integrated with the Meta Haptics SDK for Unity, Unreal Engine, and native applications. It supports the translation of audio clips into haptic feedback and offers a wide range of tools for editing. However, it is limited to native VR controllers designed for Meta VR headsets, for which it is specifically created, and does not support gamepads. Interhaptics offers a Haptic Composer tool (version 1.2.0) [54], which is used to design haptic effects that are then integrated into projects via APIs and tools provided by the Interhaptics SDK and plugins for Unity and Unreal Engine. Haptic Composer is comprehensive software tool for creating haptic effects and it supports a wide array of devices and platforms, offers a feature-rich editor with in-app preview capabilities, includes haptic effect presets, and allows for audio-to-haptics translation. However, it is important to note that both Meta Haptics Studio and Interhaptics Haptic Composer are standalone tools that are installed and used independently of the game engine. In comparison with the tool described in this paper, these solutions provide more advanced visual representations of haptic effects and expose a wider range of parameters for configuring them.