Create generate_book.py

generate_book.py

@@ -0,0 +1,108 @@
+import bpy, bmesh, json, sys, os, math
+
+# -------- parse args: blender -b -P generate_book.py -- --spec spec.json --out out_dir
+argv = sys.argv
+argv = argv[argv.index("--")+1:] if "--" in argv else []
+args = { argv[i].lstrip("-"): argv[i+1] for i in range(0, len(argv), 2) }
+spec_path = args.get("spec"); out_dir = args.get("out", os.getcwd())
+
+with open(spec_path, "r") as f:
+    spec = json.load(f)
+
+name = spec.get("name","Book")
+sx, sy, sz = (spec["size_m"]["x"], spec["size_m"]["y"], spec["size_m"]["z"])
+bevel = spec.get("bevel_m", 0.002)
+corner_caps = spec.get("corner_caps", True)
+strap = spec.get("strap", {"enabled": False})
+
+# -------- clean scene
+bpy.ops.wm.read_factory_settings(use_empty=True)
+
+# -------- build low poly book as a cube
+mesh = bpy.data.meshes.new("book_lp")
+obj = bpy.data.objects.new(name, mesh)
+bpy.context.scene.collection.objects.link(obj)
+bm = bmesh.new()
+bmesh.ops.create_cube(bm, size=1.0)  # 2m cube
+bm.to_mesh(mesh); bm.free()
+
+# scale to meters (cube size=2 → scale by half of desired dims)
+obj.scale = (sx/2, sy/2, sz/2)
+bpy.context.view_layer.objects.active = obj
+bpy.ops.object.transform_apply(location=False, rotation=False, scale=True)
+
+# bevel modifier for soft edges
+bev = obj.modifiers.new("Bevel","BEVEL")
+bev.width = bevel
+bev.segments = 2
+bev.limit_method = 'ANGLE'
+bev.angle_limit = math.radians(60)
+
+# simple spine loopcut (visual separation only; minimalistic)
+bpy.ops.object.mode_set(mode='EDIT')
+bpy.ops.mesh.loopcut_slide(MESH_OT_loopcut={"number_cuts":1}, TRANSFORM_OT_edge_slide={"value":0.0})
+bpy.ops.object.mode_set(mode='OBJECT')
+
+# optional strap
+if strap.get("enabled", False):
+    w = strap.get("width_m", 0.025)
+    bpy.ops.mesh.primitive_cube_add(size=1)
+    s = bpy.context.active_object; s.name = "strap"
+    s.scale = (sx*0.55, w/2, sz/2*1.05)
+    s.location = (0, 0, 0)
+    bool_mod = obj.modifiers.new("StrapUnion","BOOLEAN")
+    bool_mod.operation = 'UNION'; bool_mod.object = s
+    bpy.context.view_layer.objects.active = obj
+    bpy.ops.object.modifier_apply(modifier=bool_mod.name)
+    bpy.data.objects.remove(s, do_unlink=True)
+
+# corner caps (simple unions)
+if corner_caps:
+    cap_size = min(sx, sy, sz) * 0.12
+    for sxm in (-1, 1):
+        for sym in (-1, 1):
+            bpy.ops.mesh.primitive_cube_add(size=cap_size)
+            c = bpy.context.active_object
+            c.location = (sxm*(sx*0.5 - cap_size*0.35),
+                          sym*(sy*0.5 - cap_size*0.35),
+                          0)
+            bool_mod = obj.modifiers.new("CapUnion","BOOLEAN")
+            bool_mod.operation = 'UNION'; bool_mod.object = c
+            bpy.context.view_layer.objects.active = obj
+            bpy.ops.object.modifier_apply(modifier=bool_mod.name)
+            bpy.data.objects.remove(c, do_unlink=True)
+
+# apply bevel last
+bpy.context.view_layer.objects.active = obj
+bpy.ops.object.modifier_apply(modifier=bev.name)
+
+# shading + autosmooth
+obj.data.use_auto_smooth = True
+bpy.ops.object.shade_smooth()
+
+# basic UV unwrap (smart project to keep it simple for now)
+bpy.ops.object.mode_set(mode='EDIT')
+bpy.ops.uv.smart_project(angle_limit=66, island_margin=0.02)
+bpy.ops.object.mode_set(mode='OBJECT')
+
+# simple PBR material (leather)
+mat = bpy.data.materials.new("MAT_Book")
+mat.use_nodes = True
+nt = mat.node_tree
+bsdf = nt.nodes.get("Principled BSDF")
+base = nt.nodes.new("ShaderNodeRGB")
+leather = spec.get("style", {}).get("leather", "dark_brown")
+base.outputs[0].default_value = (0.12,0.06,0.03,1.0) if "brown" in leather else (0.2,0.2,0.2,1.0)
+nt.links.new(base.outputs["Color"], bsdf.inputs["Base Color"])
+bsdf.inputs["Roughness"].default_value = 0.6
+bsdf.inputs["Metallic"].default_value = 0.0
+if len(obj.data.materials) == 0:
+    obj.data.materials.append(mat)
+else:
+    obj.data.materials[0] = mat
+
+# export glTF
+os.makedirs(out_dir, exist_ok=True)
+export_path = os.path.join(out_dir, f"{name}.glb")
+bpy.ops.export_scene.gltf(filepath=export_path, use_selection=False, export_format='GLB')
+print("Exported:", export_path)