Skip to content

Climbing fractals - How volumes fit in.

"Mountains are not cones..."
Benoir Mandelbrot

For those who have not heard of fractals- a quick and very basic definition for the purposes of this post might be:


It is a concept found throughout nature, most plants and even some animals exhibit fractal patterns. The branch of a tree is essentially a smaller tree in itself. Romanesco broccoli exhibits strikingly apparent self-similarity.

In terms of climbing natural formations, the principle can be seen in the sizes if the features we are dealing with. Look at a piece of naturally weathered rock- is that groove a small crimp, a big jug, a water worn valley? it’s difficult to tell without some other frame of reference.

The natural forms we climb have featured at every scale ranging from the sub-millimetre irregularities that give us friction, through the lumps and edges the right size for our hands and feet to grip, right through to the entire boulder or even mountain on which our route lies.

But what happens when we climb indoors? Some friction giving texture is there (even on bare plywood there is some friction) and the holds can give features from a few mm to around 300 mm. But the overall geometry of the wall itself only comes into effect at about 1200mm (the short side of a plywood sheet). This is where volumes come in – to bridge the gap between the holds and the wall itself.

Why does this matter? Well, us humans are not very fractal it turns out. You would not mistake a finger for a whole person without some skilful shadow puppetry. When we interact with natural rock the scale of features suddenly matters a great deal. The effects that features of different sizes have on our bodies varies greatly.

Imagine a wall covered only in tiny mm sized bumps. The only effect on the body of someone trying to climb it would be to give you tougher skin.

Next- a wall covered with 20mm bumps. Your fingers and toes are going to get quite a workout but essentially it would be like climbing a ladder.

If we jump up to bumps of around one metre suddenly a whole lot more of your body needs to be engaged to make progress. we’re talking core strength here.

It’s at a feature size of one to two metres that we see bridging, palming spans, full-body compression and tension moves requiring continuous chains of muscular strength from one limb to another.

An absence of volumes will mean that people transitioning from indoor to outdoor climbing (as many do) will find themselves lacking in both strength and technique when faced with the more natural and organic forms. Many might be disheartened by their lack of ability in certain areas and accordingly restrict their climbing to faces which more closely resemble indoor walls, or be put off real rock altogether – A tragic failure!

Not only do volumes enable more relevant training for the outdoors, but they also enhance the indoor climbing experience in its own right. By adding a level of complexity the activity becomes more engaging and encompasses more aspects of movement. This results in greater enjoyment, interest and feeling of becoming proficient, keeping a weekly climbing gym visit varied and inspiring.

Of course, you could design the wall with integral features of this size, but then you’re stuck with that forever. Those cool shapes that look impressive in a wall design will quickly make all routes in those areas distinctly ‘samey’. A better option is to keep the basic structure simple, saving time and money.

So the perfect climbing wall formula? Keep the wall structure simple – long sweeping overhangs, thin slabs of varying angle etc. and intersperse these with volumes that can be periodically rearranged to give endless configurations of overhangs, ledges, corners and, of course, plenty of Arêtes!

Climbing Fractals – How volumes fit in

Leave a Reply

Your email address will not be published. Required fields are marked *