Cloth: What is it?

We've finally have our basic scene ready, it's time to start simulating cloth... but what is cloth? Let's take a deep dive into the world of cloth together!

Keywords: cloth simulation, fabrics, knitting, weaving

By Carmen Cincotti  

I can’t wait to continue the cloth simulation.

In recent weeks we have created a 3D scene ready to simulate fabric. However, before continuing, it may be useful for us to understand fabric.

A few questions come to my mind 🤔:

  • What are the materials used ?
  • What are the physical properties?
  • How is it made?

Blankets on a chair and table

Each fabric is different. The material used will change its properties. The construction process (weave? knit? etc.) will change its properties. To be frank, changing any of these variables should change the behavior of the final simulation because the fabric itself is different.

That said, a question that we must always ask ourselves before simulating something is:

What am I simulating?

This article will answer that question in regards to fabric. 👕

The raw materials of fabric 🧶

The three main material categories are those derived from plants, those from animals, and those that are man-made.

Common materials are:

  • Cotton - Cotton as a fabric is durable, soft, and warm. It is made of short plant fibers that are spun together to form longer threads. It wrinkles easily.


  • Linen - from the flax plant. Linen as a fabric is breathable, lightweight and moisture wicking. It is made of short plant fibers that are spun together to form longer threads. Flax fibers do not stretch. Linen is known to wrinkle easily: this is because it has low elasticity.


  • Silk - from the silkworm cocoon. Like wool, it is a protein-based fiber. Strength is one of the most interesting characteristics of silk in addition to its resistance to wrinkle.

Silk Pavilion silkworm2.jpg
By Neri Oxman - Mediated Matter Group, CC BY-SA 4.0, Link

  • Wool - harvested from sheep. Wool is supple, elastic and strong- which makes it durable and wrinkle-resistant.

Wool from sheep

  • Polyester - made of a man-made filament that is usually derived from petroleum. Polyester fibers are incredibly strong, which means they won’t tear or stretch like cotton and other natural fibers. Polyester is wrinkle resistant.

Stretching Polyester.JPG
By Bearas - Own work, CC BY-SA 4.0, Link

The fabrication process 🧵

With our raw materials, we are almost ready to manufacture the fabric. There are several methods to create fabric as we know it, such as weaving or knitting.

First, we will see how the fibers are transformed into threads. For the next few examples, let’s assume we’re following the fabrication process of one of the most used materials in fashion and textiles - cotton.

Spinning from fiber to yarn

After growing, harvesting, separating and ginning cotton, it’s time to form a thread.

L'égrenage du coton

By spinning fibres, yarn is made. The idea is that this process holds the fibers firmly together.

2013-04-19 hangewickeltes Knäuel.jpg
By Marion Scheffels - Self-photographed, CC BY-SA 3.0 de, Link

There are two properties of yarn that will change its character:

  1. Twist - the direction in which it has been spun or twisted.
    • Z-twist: the thread is spun or twisted clockwise.
    • S-twist: the thread is spun or twisted anti-clockwise.

Twist of yarn

  1. Ply - The ply is the number of yarns that are twisted together to form a single yarn. Two or more spun yarns can be twisted together to form a thicker yarn which is then woven into the fabric. Two-ply fabrics are generally superior to single-ply fabrics

What spinning methods exist?

In the past, the vast majority of spinning was done with a spinning wheel. The fibers are pulled through a wheel and as it spins the fibers are collected on a cylindrical object called a spool.

Nowadays, spinning methods are more complex thanks to technological advancements although the general idea remains the same. Here is this resource to learn more.


To weave the threads, we use a loom. I swear, the videos on how to use it are truly a pleasure to watch.


After weaving on threads with a loom, we should have fabric that we can use as we please! 🥳

Cloth example

If we look closely at a woven fabric, we would only see the lines of threads interwoven perpendicularly. The longitudinal threads are called warp threads and the perpendicular threads are weft threads.

Warp and weft example


Of course, there are other ways to make fabric. For example, knitting is very popular.


It is made up of stitches which are loops of threads that intertwine. The knitter makes the knit with the help of needles. 🪡

Knitting loops

Knitting versus weaving

There are two important points to keep in mind when simulating these fabrics:

  • Stretchiness - A knit fabric can stretch more than a woven fabric.
  • Resistance - A knitted fabric stretches in all directions which gives it a supple character while the weave limits movement, especially in the vertical direction.

Next time

We will see how to model the physical forces that are in a piece of fabric.


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Written by Carmen Cincotti, computer graphics enthusiast, language learner, and improv actor currently living in San Francisco, CA.  Follow @CarmenCincotti


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