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Lab5

BTD/Modul 5: Übungen

Aufgabe 1: Prozedurales Geometry Nodes Tool

• Parametrisches Tool mit Geometry Nodes erstellen (z.B. modulare Wände, Geländer).
• Parameter: Länge, Höhe, Segmente, Materialzuweisung.

Aufgabe 2: Partikel- und Fluid-Simulation

• Partikel- oder Fluid-Simulation einrichten.
• Simulation als Cache-Datei exportieren (z.B. Alembic).
• Bonus: Script für automatisches Baking aller Simulationssysteme.

Aufgabe 3: Simulation Cache Management Script

• Script prüft Simulation-Caches in der Szene.
• Ausgabe: Typ, Dateigröße, letztes Update.

Material:

Crowd-Sim mit Mesh-Deformation und Agentenbewegung

Ein prozedurales Gelände-Mesh ist die Grundlage für die Bewegung der Agenten (rote Kegel).

import bpy
import math
import random
from mathutils import Vector

# -----------------------------
# CLEAN SCENE
# -----------------------------
bpy.ops.object.select_all(action='SELECT')
bpy.ops.object.delete()

# -----------------------------
# PARAMETERS
# -----------------------------
AGENT_COUNT = 50
SURFACE_SIZE = 10
TIME_SCALE = 0.03
WAVE_AMPLITUDE = 1.0
NOISE_SCALE = 0.7
AGENT_SPEED = 0.4

# -----------------------------
# CREATE SURFACE
# -----------------------------
bpy.ops.mesh.primitive_grid_add(
    size=SURFACE_SIZE,
    x_subdivisions=200,
    y_subdivisions=200
)
surface = bpy.context.object
surface.name = "Procedural_Surface"

# Subdivision for smooth deformation
sub = surface.modifiers.new("Subd", 'SUBSURF')
sub.levels = 2

# -----------------------------
# CREATE AGENT MESH
# -----------------------------
bpy.ops.mesh.primitive_cone_add(radius1=0.1, depth=0.4)
agent_mesh = bpy.context.object
agent_mesh.name = "AgentMesh"
agent_mesh.hide_viewport = True
agent_mesh.hide_render = True

# -----------------------------
# AGENT COLLECTION
# -----------------------------
agents = []

for i in range(AGENT_COUNT):
    obj = agent_mesh.copy()
    obj.data = agent_mesh.data.copy()
    bpy.context.collection.objects.link(obj)
    obj.name = f"Agent_{i:03d}"
    obj["seed"] = random.uniform(0, 1000)
    agents.append(obj)

# -----------------------------
# SURFACE DEFORMATION HANDLER
# -----------------------------
def deform_surface(scene):
    t = scene.frame_current * TIME_SCALE
    mesh = surface.data

    for v in mesh.vertices:
        x, y = v.co.x, v.co.y
        wave = math.sin(x + t) * math.cos(y + t)
        noise = math.sin((x + y) * NOISE_SCALE + t)
        v.co.z = wave * WAVE_AMPLITUDE + noise * 0.5

    mesh.update()

# -----------------------------
# AGENT MOTION HANDLER
# -----------------------------
def animate_agents(scene):
    t = scene.frame_current * TIME_SCALE
    depsgraph = bpy.context.evaluated_depsgraph_get()
    eval_surface = surface.evaluated_get(depsgraph)
    mesh = eval_surface.to_mesh()

    for obj in agents:
        seed = obj["seed"]

        # Parametric movement
        u = (math.sin(t + seed) + 1) * 0.5
        v = (math.cos(t * 0.7 + seed) + 1) * 0.5

        x = (u - 0.5) * SURFACE_SIZE
        y = (v - 0.5) * SURFACE_SIZE

        # Raycast to surface
        hit, loc, normal, _ = eval_surface.ray_cast(
            Vector((x, y, 10)),
            Vector((0, 0, -1))
        )

        if hit:
            obj.location = loc
            obj.rotation_mode = 'QUATERNION'
            obj.rotation_quaternion = normal.to_track_quat('Z', 'Y')

    eval_surface.to_mesh_clear()

# -----------------------------
# REGISTER HANDLERS
# -----------------------------
bpy.app.handlers.frame_change_pre.clear()
bpy.app.handlers.frame_change_pre.append(deform_surface)
bpy.app.handlers.frame_change_pre.append(animate_agents)

# -----------------------------
# TIMELINE SETUP
# -----------------------------
scene = bpy.context.scene
scene.frame_start = 1
scene.frame_end = 500

print("Procedural animation demo initialized.")