🔹 Editable Poly – Polygon Smoothing & Finalizing 🔹

Now that we've covered polygon selection and editing tools, let's go deeper into smoothing groups, finalizing geometry, and optimizing for exports.

1️⃣ Smoothing Groups – How They Work

Smoothing groups control how polygons blend together in shading. If you’ve ever seen weird shadows or sharp edges that shouldn’t be there, it may be due to incorrect smoothing.

✅ Basic Smoothing Group Rules

• Same smoothing group → Smooths together (good for curved surfaces like spheres).
• Different smoothing groups → Creates a sharp edge (good for mechanical hard surfaces).
• Unsmoothed (no group assigned) → Faces appear faceted, like low-poly models.

✅ How to Use Smoothing Groups

1. Select your polygons (use Ctrl+Click or double-click to select entire elements).
2. In the Modify Panel, scroll down to "Polygon Smoothing Groups".
3. Click on a number (1–32) to assign that group.
4. To remove a smoothing group, deselect all numbers (it will become faceted).

2️⃣ Practical Smoothing Examples

🔸 Hard Surface Example (Box Edges)

• A cube should have sharp corners.
• Select each side separately and assign different smoothing groups.
• This prevents shading from blending across sharp edges.

🔸 Organic Surface Example (Sphere)

• A sphere should have smooth shading across the entire surface.
• Assign the same smoothing group to all faces.

3️⃣ Auto Smoothing & Manual Adjustments

✅ Auto Smooth (Quick Method)

• Select all polygons.
• Click the Auto Smooth button.
• Adjust the angle threshold:
  • 30°–45° for hard surfaces.
  • 60°+ for soft, organic surfaces.

✅ Manual Smoothing (For More Control)

• Use individual smoothing group numbers for complex models.
• Useful when Auto Smooth doesn’t work correctly.

4️⃣ Finalizing & Preparing for Export

🔸 Reset XForm (Before Exporting)

• Ensures all necessary transforms (scale, rotation) are 100% reset.
• Go to Utilities → Reset XForm → Reset Selected.

🔸 Collapse Modifier Stack

• Convert everything to Editable Poly before exporting.
• Right-click → Convert to Editable Poly.

🔸 Check for Errors

• Use STL Check (Modifier) → Finds geometry issues.
• Use "Unify Normals" if some faces look flipped.

⚡ Quick Tips for Best Geometry

✅ Always check smoothing before exporting!
✅ Use Auto Smooth for quick results, manual smoothing for precision.
✅ Reset XForm to avoid scale/rotation issues in game engines.
✅ Use STL Check to find any bad geometry.