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Fire and Ice

Responsible for FX, Modeling, Texturing, Lighting

Software: Houdini

Programming Language: Python

Fire and Ice was a project created to experiment with motion capture data in Houdini. Based on the data and base code provided by Professor Deborah Fowler, the python script I wrote takes the data and processes it into a series of text files usable by a Houdini script. Various pyro simulations and a rigid body dynamics system with the motion capture animation created this elemental showdown.

Simulations

A total of four pyro simulations and one rigid body dynamic system create the effects in the scene. The pyro simulation is sourced from the characters and swords, respectively, and uses a similar setup for each simulation.

Shattering the fire sword is created using a rigid body dynamics system and Voronoi fracturing node. A shift in textures from hot magma to solid rock aids the sword’s cooling and breaking effect.

An attribute transfer with a pyro burst sourcing creates the superheated steam bursting from the swords’ collision.

Character Creation

The data was split into various body parts when creating the character geometry. This division allowed greater control over the final look of the character’s body and resulted in more apparent animation overall.

A VOP network with worley noise creates the magma character’s body. The resulting displacement is mapped into the material’s emission parameters to make the character’s lava and hardened magma texture.

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Python

# mocapParser.py

# Author: Nathan Huseth

# Date: 5/22/2022

# input: Text file with motion capture data

# output: Multiple Text files with marker data

# Description:

# A program which processes motion capture data, splits frame data,

# formats marker data to a new line and saves a corresponding text file

import os

import tkinter

from tkinter import ttk

from tkinter import filedialog

class ProcessMocap():

# Initialize Class

def __init__(self, outputDir = “output”):

self.padx = 10

self.pady = 10

self.outputDir = outputDir

return

# Open files

def openFiles(self):

# Get files as user input

self.files = filedialog.askopenfiles(title=“Source Directory”, initialdir=“.”, filetypes=[(“Text Files”,“*.txt”)])

# Iterate each file

for textFile in self.files:

# Get name of file

name = textFile.name.split(‘/’)

name = name[–1]

name = name[:–4]

print(“\nProcessing: “ + name + “.txt”)

# Define output directory name

if(self.outDirectory.get().strip() != “”):

self.outputDir = self.outDirectory.get()

# Process Data

self.processFile(textFile, name)

# Close file

textFile.close()

print(name + “.txt finished.”)

print(“\nAll files completed and waiting in /” + self.outputDir + ” directory”)

return

# Controls file processing

def processFile(self, data, name):

# Remove header line

data.readline()

# Create output directories

directory = self.createDestination(name)

# Iterate each line

for line in data:

splitData = line.split()

result = “”

# Iterate each value in line

for index, i in enumerate(splitData):

# Handle frame number

if(index != 0):

# Define result data, newline every third value

result += i + ” “

if((index–1)%3 == 2):

result += “\n“

else:

frame = i

# Save output file

self.saveFile(frame, directory, result)

return

# Create GUI

def createGUI(self):

# Setup window

root = tkinter.Tk()

root.geometry(‘380×190’)

root.title(“Parse Mocap Data”)

frame = ttk.Frame(root)

frame.grid(padx=self.padx, pady=self.pady)

# Output directory

self.outDirectory = tkinter.StringVar()

# Create button and instructions

info = ttk.Label(root, text=“Use the button below to select text files containing mocap data.\nEach frame will be exported as a formatted text file with marker\npositions.”)

outLabel = ttk.Label(root, text=“Output directory name.\nDefaults to \”output\” when blank”)

outDir = ttk.Entry(root, textvariable = self.outDirectory)

directory = ttk.Button(root, text=“Select and process files”, command=self.openFiles)

# Layout elements

info.grid(row=1, column=1, columnspan=2, sticky=“w”, pady=0)

outLabel.grid(row=2, column=1, sticky=“W”, pady = self.pady)

outDir.grid(row=2, column=2, sticky=“W”, pady = self.pady)

directory.grid(row=3, column=2, sticky=“w”, pady=self.pady)

root.mainloop()

return

# Save text file

def saveFile(self, frame, directory, data):

name = “out.” + frame + “.txt”

newFile = open(self.outputDir + “/” + directory + “/” + name, “w”)

newFile.write(data)

newFile.close()

return

# Create directories

def createDestination(self, directory):

# Main output directory

if(os.path.isdir(self.outputDir) == False):

os.mkdir(self.outputDir)

# Frame directory

if(os.path.isdir(self.outputDir + “/” + directory)):

return directory

else:

os.mkdir(self.outputDir + “/” + directory)

return directory