Parametric Playmat Ring (MTG/TCG) with Inner Anti-Slip Ribs — Split, Squeezed Fit

Keep your playmat neatly rolled and bag-friendly with this lightweight, parametric playmat ring. The split design gives a gentle squeeze so the mat doesn’t unwind in your backpack, while the outer micro-ribs improve grip and the inner anti-slip ribs lightly “catch” the mat without biting into the fabric. Both rib sets are smartly trimmed around the gap so the ring flexes cleanly when you slide it on.

Why this design

• Parametric: Inner diameter, width, wall thickness, gap angle, and rib geometry are all editable in the source.
• Controlled squeeze: extra_squeeze lets you dial in a preload for a secure but gentle hold.
• Clean flex zone: Ribs don’t cross the split — less snagging, smoother on/off.
• Print-friendly: No supports, stable orientation, fast print.

Recommended print settings

• Orientation: Print standing upright on the ring’s side (gap vertical). Add a short brim if your adhesion is weak.
• Material: PLA or PETG. PLA-CF works great for a stiff ring; PETG adds toughness. TPU is possible for a softer feel — increase wall thickness if needed.
• Layer height: 0.2 mm (or 0.16 mm for crisper ribs).
• Walls/Perimeters: 3–4.
• Infill: 0–15% (most strength is in the walls).
• No supports.

Sizing tips

• Measure your rolled mat diameter. Set inner_diameter a little smaller (0.5–1.0 mm) than the measured roll and use extra_squeeze (e.g., -0.5) for a snug fit.
• Need more grip? Increase inner_rib_depth slightly (e.g., 0.6 → 0.8 mm).
• If insertion feels too tight at the split, raise rib_gap_extra_deg (e.g., 2 → 4–6°).

Param overview (in the .scad file)

• inner_diameter — base diameter before squeeze
• ring_width — axial width
• wall_thickness — radial wall thickness
• gap_angle — split angle for flex
• extra_squeeze — negative values preload the fit
• Outer ribs: outer_ribs_count, outer_rib_height, outer_rib_thickness
• Inner ribs: inner_ribs_count, inner_rib_height, inner_rib_depth
• rib_gap_extra_deg — angular margin without ribs around the split

If you tweak the parameters for a special mat (thicker, thinner, extra-wide), share a make with your values — it helps others!