The input material details a project involving conceptualization, mechanical design, prototyping, and advanced Computer-Aided Design (CAD) workflows, specifically focusing on Virtual Reality (VR) peripheral development and utilizing additive manufacturing technologies (3D printing, SLS), reverse engineering (3D scanning, NURBS surfacing), and topology optimization (generative design).
Adopted Persona: Senior Product Design and Additive Manufacturing Engineer.
Abstract:
This project outlines the development and refinement of a custom, highly functional Virtual Reality (VR) gun stock designed to improve aiming stability and user immersion in VR shooter games. The methodology leveraged ergonomic principles derived from real-world firearm stocks, circumventing unreliable manual measurements. Key technical challenges addressed include achieving secure, non-fatiguing controller attachment and maximizing structural efficiency while minimizing weight. The solution involved custom 3D scanning and reverse engineering the controller battery lid geometry to create a robust attachment mechanism, followed by combining it with a grip cup design. The core stock structure was optimized using generative design (Fusion 360) under specified load conditions and manufacturing constraints (Additive/FDM, 45-degree overhangs, 1mm minimal thickness), resulting in an organically structured, lightweight component. The final prototype integrates on-the-fly adjustable length via a compliant mechanism ratchet system and features magnetic separation for rapid detachment and reattachment of the front controller. The final high-strength model was fabricated via Selective Laser Sintering (SLS) using PA12.
Summary: Exploring the Development of a High-Performance VR Gun Stock
0:55 Motivation and Problem Statement: The high difficulty in aiming accurately during VR shooter games using loose controllers necessitated the creation of a custom VR gun stock to provide stability and immersion.
1:36 Design Strategy: Initial attempts to measure required dimensions based on in-game controller holding proved inconsistent. The designer pivoted to reverse engineering and measuring the established ergonomics of a real-world gun stock to ensure proper stability, arm positioning, and sight acquisition.
2:11 Core Design Requirements: The stock required several simultaneous features: lightweight construction, on-the-fly adjustability, aesthetic appeal, and secure, non-slip controller attachment.
3:31 First Prototype Iteration: The initial prototype was functional but bulky, incorporating key features: a soft TPU rubber shoulder pad, a height-adjustable cheek guard achieved via a PLA-based compliant mechanism (no moving parts, utilizing material flex), and an adjustable length mechanism utilizing a large lever to retract a central locking pin/ratchet.
6:04 Controller Attachment Issues: Existing 3D printable "cup" attachments found online caused user fatigue, as constant gripping was required to prevent the heavier stock from sliding out.
6:46 Proposed Solution (Battery Lid): The designer conceived using the controller's click-in battery lid attachment mechanism as the primary connection point due to its security. Initial attempts using existing 3D models of the battery lid proved structurally suboptimal, leading to fit issues and breakage under leverage/back weight.
7:58 Reverse Engineering the Geometry: To achieve a precise fit, the battery lid was 3D scanned. The resulting STL mesh data required conversion to usable CAD volumetric data (STEP/NURBS). Standard conversion tools failed.
9:13 Specialized Conversion Software: The external program "Quick Surface" was used successfully to reverse engineer the scan data. This process involved polygon reduction and automated NURBS resurfacing to generate a precise, workable STEP file for use in Inventor CAD software.
12:46 Attachment Hybridization: The final controller attachment solution combined the secure, non-fatiguing click-in feature (derived from the reverse-engineered battery lid) with the added structural support and grip area of a surrounding "cup."
13:29 Magnetic Separation Feature: Neodymium magnets and metal plates, arranged hexagonally, were incorporated to allow the front and back sections of the stock to snap together quickly, enabling users to separate and re-adhere the components blindly for actions such as looting or reloading.
14:10 Generative Design Implementation: Fusion 360 was utilized to perform topology optimization, aiming for minimum weight and organic aesthetics.
15:07 Constraints: Key areas (shoulder pad contact, cheek guard contact, front attachment) were marked for preservation. A volume restriction was applied to prevent material intrusion into necessary functional space.
15:47 Load Cases: The design was tested under multiple realistic load conditions, including 5 kg of push force, 1 kg of gravity/pull, and a 30 Nm rotational moment, to ensure structural integrity across varied use.
17:48 Manufacturing Constraints: The calculation was specified for additive manufacturing, defining the Z-axis print direction, restricting overhangs to 45 degrees, and setting a minimal wall thickness of 1 mm.
21:16 Final Prototype and Manufacturing: The final design featured a streamlined, organically grown structure. The adjustable length ratchet mechanism was refined for a professional look while retaining the compliant bending functionality. The model was fabricated using high-strength PA12 via Selective Laser Sintering (SLS), sponsored by PCB Way, offering industrial-grade strength.
22:31 Core Functionality Confirmation: The final stock confirmed all desired features: secure controller click-in, simplified on-the-fly length adjustment (with a range suitable for small to very long virtual weapons), adjustable cheek rest height, and magnetic separation for independent hand use.
23:59 Availability: The 3D printing data is available for public download (PLA or PETG compatible) on the designer's Maker World and PCB Way accounts.