Blender

## Transforms - Apply scale before export — `Ctrl+A` → Scale, or objects deform in game engines - Apply rotation for correct orientation — especially for rigged models - Non-uniform scale breaks modifiers — apply scale before Mirror, Bevel, etc. - Reset transforms: `Alt+G/R/S` — location, rotation, scale to defaults ## Object vs Edit Mode - Object mode transforms affect whole object — Edit mode transforms geometry only - Modifiers applied in Object mode — Edit mode shows base mesh - Selection works differently — Object selects whole, Edit selects vertices/edges/faces - `Tab` to toggle — most operations mode-specific ## Normals - Flipped normals = invisible faces — `Shift+N` to recalculate outside - Check in Viewport Overlays → Face Orientation — blue is correct, red is flipped - `Ctrl+Shift+N` for flip inside — useful for interior scenes - Smooth shading issues = bad normals — recalculate first ## Modifiers - Order matters — Mirror before Subdivision, Bevel before Mirror typically - Apply modifiers for export — game engines don't understand Blender modifiers - Array + Curve = deformation issues — apply Array first, then Curve - Subdivision preview vs render levels — set same for consistent export ## UV Unwrapping - Mark seams where texture can split — `Ctrl+E` → Mark Seam - Seams at hidden areas — under arms, behind ears, model edges - `U` → Unwrap after marking — Smart UV Project as fallback - Check UV overlap — causes baking issues, separate islands ## Origin Point - Origin affects rotation/scale pivot — `Right-click` → Set Origin - Origin to geometry for centered pivot — Origin to 3D Cursor for precise placement - Origin matters for game engine import — often should be at feet/base ## Export for Game Engines - FBX or glTF for Unity/Unreal — glTF for web - Apply transforms on export — "Apply Scalings: FBX All" for Unity - Forward axis: `-Z Forward`, Up: `Y Up` for Unity — different for Unreal - Embed textures or pack separately — depends on workflow ## Python API (bpy) - `bpy.context` is current state — selection, active object, mode - `bpy.data` is all data — access any object by name regardless of selection - `bpy.ops` are operators — require correct context (mode, selection) - Override context for operators — `{'object': obj, 'selected_objects': [obj]}` - Most ops need Object mode — `bpy.ops.object.mode_set(mode='OBJECT')` first ## Common Mistakes - Duplicate with Alt+D creates linked copy — changes affect both, use Shift+D for independent - Delete vs Dissolve — Delete removes geometry, Dissolve merges (Edit mode) - Proportional editing left on — affects unexpected vertices, check header - Subdivision on high-poly crashes — start with Levels: 1, increase gradually - Materials not linked to object — won't export, must be assigned to faces