Project Goal: Create a 3D-printable CAD model (STEP and STL) for a handheld acoustic device, optimized for PolyJet Multi-Material printing. 1. Primary Geometry (The Shell) Form Factor: Contoured "mask" shape covering the mouth and chin with a deep bridge cutout for nose/eye clearance. Dimensions: 5.0" W x 4.5" H. Nominal wall thickness of 0.25" (1/4 inch). Finish: All edges must be generously radiused (smooth, rounded) for safety. 2. Functional Feature: Acoustic Black Hole (ABH) Array Feature Type: Precision-machined "dimples" on the exterior. The Math: Each dimple follows a quadratic power-law taper (h(x) = \epsilon x^m, where m \geq 2). Center thickness should be 0.04" (1mm). Aesthetic Pattern: Arrange these circular ABH dimples in a heart-shaped array on the front shell. 3. Integrated Grip (Enhanced Ergonomics) Design: A "C-shaped" grip integrated into the cheek/side contour. The "Security Lip": Along the inner edge of the grip (closest to the center of the shield), include a raised bolster/ridge (approx. 0.25" height). This provides a physical stop for the fingertips to pull against. Texture: Apply a micro-dot or "knurled" texture to the grip surface for maximum friction. Multi-Body Requirement: Model as a separate body for material assignment (Rigid Mauve Shell vs. 70A Shore Grey Grip). 4. Interior Specifications Surface: Interior must be smooth for secondary bonding of a 1/8" acoustic felt liner.