Light and Motion in Curtains - Exploring the Simulation of Cloth

Daniela Covarrubias

4.566 Advanced Project in Digital Media
Development: September-December, 2013
Instructor: Prof. Takehiko Nagakura

Cloth Simulation with Wind and Light

This was one of the first cloth simulations I was able to successfully demonstrate

Movie info: mp4, 10 second loop

Project Overview

My thesis proposes a study of the curtainís potentials in order to design from the inside out. Instead of attacking problems of flexibility and temporariness with heavy infrastructure, I propose to attack the problem by starting with the inside, focusing on the interactions that fuel or result from this kind of space. Instead of considering the curtain merely as a supplement to the wall, it can take on the primary role in the definition of space. A role which inherently forces consideration of questions too easily overlooked in the aggregation of a typical wall system. Not only does fabric imply flexibility, fabric can imply the mediation of light, temperature, sound, color, and privacy. And even beyond those functional behaviors, fabric has a qualitative aspects that arenít directly functional but provide the depth of interaction and familiarity that makes the curtain so much more than its hard counterpart. The curtain reacts to wind and movement that causes it to move. The curtain makes a faint rustling sound that indicates its movement. The curtain not only provides light control, but it produces variable light through its material and color and through its folds and drapes. The curtain can regulate varying dimensions within the room. And further, the curtain encourages touch, whether the faint brush of the fabric as it blows in the wind or the intentional interaction of drawing the curtain.

Considering these many qualitative aspects of the curtain, the challenge of representation is particularly limited by a two-dimensional drawing. The subtleties of fabric in a physical environment require a more expansive description, which can be achieved through simulation and animation. For this class, I chose to explore methods of simulating the interaction of fabric with various environmental factors, including wind and air movement, mechanical force, and light. I did this initially by setting up a simple scenario of a plain curtain and a window. Next, I explored the simulation of a set of prototypes that I developed as part of my thesis.

Project Framework

1. Software: 3ds Max Design 2014 (chosen for its existing physics simulation tools and relative ease of use)
2. Simulation: Controlling physical properties of the cloth and manipulating strength of physical effects
3. Rendering: Controlling visual properties of cloth and manipulating light effects

This is a screenshot of the simulation process in 3ds Max

Wind and Light

As a first introduction to 3ds Max and the tools of cloth simulation, I set up a simple window scenario in which a gust of wind would cause the curtain to move and allow light into the room. This simulation uses specific cloth properties embedded into 3ds Max and the wind force with varying degrees of strength. The rendering is done with VRay.

Movie info: mp4, 10 second loop

Motion and Light

As I became more familiar with the 3ds Max software, I was able to rig a simulation of the cloth for the appearance of being manipulated by an independent force (like a person pulling the curtain to one side). And again the movement of the curtain affects the light in the room.

Movie info: mp4, 15 second loop

Prototype 1: Carved Layers

In this example, Iím primarily trying to produce something which can modulate acoustical qualities of a space, but by producing a system that is made up of layers of translucent material, I can also achieve something which is compressible (so you can put it away when you donít need it) and something which still allows light and reduced visibility through. The simulation serves to demonstrate the slight movement of each individual layer and its movement as a whole when retracted.

Movie info: mp4, 15 second loop

Prototype 2: Infinite Configurations

In this example, the curtain is released from its linear track and allowed to travel freely across an entire plane (whether with magnets or another system), which means an almost infinite reconfigurability of space. The simulation serves to suggest how the cloth reacts when manipulated from single independent points.

Movie info: mp4, 21 second loop

Further Development

My hope in this class was to find a tool with which I could quickly iterate scenarios of curtains with motion and light in a way that could act as an intermediary between making scale models and producing full scale curtains. Although I was able to simulate cloth with 3ds Max, there were many limitations to this process. The nature of cloth simulation requires a pretty high polygon count in order to produce realistic simulations and this slows down the simulation process significantly. So much so that even the simplest simulations could take many minutes to complete, making the iterative process of making small changes and testing the result quite painful. However, based on a few examples I have seen of scripts that use basic physics libraries to simulate cloth, there is hope that a custom made tool could perhaps more economically produce quick iterative simulations. I also quickly learned that rendering of cloth with any level of translucency is a costly process, especially when making animations. However, it is encouraging to note that even the simplest wireframe capture of the cloth can also be quite evocative. I hope to continue my development of curtain simulations either by streamlining my process in 3ds Max or developing a custom tool.


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