Footwear that follows function

On the design principle behind Crocs

Dheeraj Nanduri


Ever heard of the phrase — form follows function?

Bet, you have. In fact, the correct and original phrase was — form ever follows function. Coined by the architect Louis Sullivan with regards to architecture, it is actually more of a general principle on how any good design is. An axiom, if you will. Meaning, if the form is flawed, then the function it is serving will inevitably be flawed (and vice-versa).

Though this was meant to talk about good architecture, we can apply this axiom to design of any kind.

Understanding — Form follows function — in product design

The form includes both the visual and physical aspects; essentially, anything that is the interface between the user and the product. A function is, simply, any requirement the product intends to satisfy.

Earlier, with the lesser number of needs people generally had, designing products were a little easier. The needs grew rapidly with development in technology; this has affected any product that is built on technology more than the ones not.

To explain the above, let’s take two products — a scissor and a watch.

A scissor is one of the most commonly used and beautiful examples for this axiom. The function of a scissors is to cut into objects and nothing else. So, it might seem like this product just has one function. But, no. There is one more important function — to enable the user to hold the product. Therefore, two necessary functions.

Function 1: To cut — the metal ends of the scissors are made to be incredibly sharp.

Function 2: To hold — the handles are shaped uniquely to enable only your thumb to go into one hole and other fingers into the rest. Therefore, you can never use it wrongly.

But do note, there can be more and more functional requirements added to this product. Some examples: blunt ends on the cutting edge, colour preference on the handles, handles of different materials, etc… That being said, one can agree that the general form of a scissors hasn’t changed much over the years.

Let’s take a look at watches. Earlier, watches were purely mechanical in nature and then digital watches were created. So, the entire watch industry has been disrupted to create a new type of looking watches.

Since, they’re dependant on technology, the number of functions that can be introduced into a watch have grown rapidly and will keep growing as well.

The number of functions for a watch, especially digital are incredible high in number and the form, thus, has been changing and will continue to change.

Of course! there’s a general design language and other technical parameters involved in watch design which are maintained. But, it clearly shows how the function can change a form of a product domain rapidly.

Crocs — footwear that follows function

Crocs have been quite controversial in their appeal — and the common consensus is that of its looks. Over time, however, it has created its own following and has now gone on to become a fashion statement of its own — especially with many A-list celebrities endorsing it.

Originally developed as a boating shoe with a foam that was produced by another company, the founders have almost sold 300 million pairs in over 90 countries since the company’s inception.

The original Crocs footwear developed are called Clogs. And, clogs weren’t designed to be fashionable. They are more of protective foot covers.

Clogs, traditionally, are hard wooden shoes, used across many geographies of the world — often associated with the footwear of the working class and farmers.

Over time, they have created an entire range, following the success of their clogs and they have been fairly doing well too.

How did Crocs become so successful?

The simple answer is — their form follows the most important functions required of footwear.

While most brands focused on building shoes for a specific domain (eg. Nike for Sports), Crocs focused on the general functions of footwear itself. Though, maybe not exhaustive, some of them are as below:

  • Cover the foot effectively
  • Soft sole
  • Breathability
  • Fashionable
  • Environment proof (rain, slush, etc.,)
  • Easy to maintain

At all these points, Crocs tends to do a great job. In fact, the fashionable is the only controversial one with the rest being generally agreeable to most of them.

In addition to the above, Crocs does one more great thing — adaptability.

Adaptability in Crocs are two things — a wide variety of colors for each of their models (adaptability to each wearer) AND fitting to a particular footwear genre (adaptability to many occasions). This is almost never seen in any other brand. The offering of so many color options virtually reduces the possibility of a wearer rejecting a shoe if he or she likes the fit of it. Also, since the footwear doesn’t fit onto a particular type of footwear, they go with everything (yay!).

Design breakdown of a typical Crocs pair

For this article, I shall only talk about the standard classic version of Crocs — the clogs.

The Foam

“It feels so bouncy”, “The softness is unparalleled”, “It’s so easy to clean”, “I feel like I am floating”— are some very common statements you would have come across from various Crocs wearers. ALL these are attributed to the Crocs foam, Croslite.

There are two types of footwear foam used, generally, the open-cell type and closed-cell type. The open-cell type is very soft but it absorbs moisture (sweat, water etc.,) and holds the foot. The closed-cell type doesn’t absorb moisture but is very hard. Many footwear brands use a combination of these foams as layers to provide comfort — for example, the soft layer open-cell layer touches your foot and the hard closed-cell layer is below it. But this isn’t totally effective as well, since the open-cell interacts with your foot and starts stinking over time.

ENTER CROSLITE — Croslite is a foam that is owned and patented by Crocs that has the best of the both worlds, open-cell and closed-cell. Therefore, it is very light, and holds the foot while being moisture resistant.

Besides that, the Croslite foam has the best-in-industry load distribution and impact absorption capabilities. Load distribution is how the foam distributes the weight applied by the wearer on it throughout the sole. Impact absorption is the reduction of shocks the footwear takes from the ground and passes onto the wearer’s body.

Therefore, Crocs enables the user to have a cushioned effect throughout the period of wearing it. This also increases the time a user wants to spend wearing the shoe and therefore, a user’s most preferred footwear choice.

On top of it all, the foam is incredible because it can be cleaned and maintained easily.

Low-Maintenance is one of the most impacting design features of Crocs.

The Sole

The sole is made from the Croslite foam as well.

This enables the sole to be incredibly flexible. The pattern present under the sole make the Crocs very slip resistant. Combine this with the exceptional load distribution and impact absorption capabilities — it makes for an ideal companion for almost any outdoor activity.

Another beautiful feature of the Croslite sole is the ability for it to effectively take the wearer’s foot shape over time. This is common with most footwear but is more pronounced here due to the sole being completely made out of foam.

The upper

The upper of the Crocs shoe, in clogs, is made of Croslite but there are other variants as well. Some have a loafers structure where the upper is made of fabric or leather. The classic clogs, and their highest selling footwear, share this common structure — described as ugly by some.

The structure is fairly simple to understand, the dome like structure ensures a protective cover over the full foot at the front and the back has a strap to hold the foot in place. The Croslite helps majorly here because, the upper is now a flexible structure along with the sole and therefore, has a great bending ability. Since it is not made of cloth or other fabric materials, it doesn’t tear out so easily either.

Another great feature are the holes. The holes play a very important role in making the Crocs wearable throughout the day and all around the year. Since, it doesn’t fully enclose the foot, the odor or moisture isn’t captured inside. Moreover, the strategic placement of the holes on the top and in the side ensure optimum ventilation inside the footwear (also, great for water to get out if you are playing in water!)

Best Footwear? — Umm…

Though the design is widely appreciated, there are a few drawbacks to the design.

  • The spacious inner structure provides a lot of breathing space but also produces a lot of foot movement freedom. The footwear doesn’t grip your foot. This has attracted a lot of criticism even from the health front from podiatrists. Therefore, it isn’t suitable for walking/running intensive activities
  • Adaptability to various foot types — even though the company claims it supports feet of all kinds, it isn’t entirely true. People have varying levels of feet flatness and these might not be suitable for all kinds.
  • Lack of adequate heel support is a big problem in the Crocs. Over time, this can create a lot feet issues for people.

Final thoughts

Though these Crocs have their share of drawbacks, they have become increasingly popular among people of all ages. It’s unisex appeal is yet another added bonus.

These shoes were created for people to laze around and they serve that function very well. While Crocs may never replace big brands like Nike, Adidas or Under Armour, they’re going to be on the shelves for a pretty long time. (Yes, including those bright green and pink ones!)



Dheeraj Nanduri

Observer by habit, Designer by nature. I write on products, advertising, marketing and the design philosophies behind them.