How This Chalk Artist Creates Illusions on Pavement

[Narrator] These illusions pop off the pavement

into the real world and are created by this man,

former NASA illustrator-turned-3D artist, Kurt Wenner.

What illusion does, fundamentally,

it tells us or reminds us that everything we think is real

is in some way an illusion.

The geometry of the illusions is very precise

and they're made to be seen from exactly one point in space.

Here was a work where I designed

the central figure of Bacchus.

The work's called The Wine Fountain.

Piece is enormous.

Each one of these squares is quite large as well,

you can see by the people sitting on the work

[Narrator] Mapping this precise visual geometry begins

with diligent planning using pencil and paper.

So here's an example of how I start a picture.

Here, I start with the grid, and then on top of the grid,

I start to compose using what's called the thumbnail sketch.

Thumbnail sketch, because one of these horse's heads

is literally the size of my thumbnail.

The information from each one of these squares

is going to then be turned back into a real square,

meaning X equals Y.

And so what we see here is that,

when we're toward my viewpoint,

this is very much like a normal square.

I have to distort it very little.

This square I have to distort more,

this one I'll have to distort more, and so on and so on

until I have to really blow this square out

to get it back into a square.

Starting from the thumbnail, I then work my way up

to a more finished line drawing.

And then what happens here is I scan

and print the little detail on another piece of paper,

which looks a lot rougher, and then I refine the detail

on this and then I cut them together.

This whole composition here needs to be blown out

in the sense that I have to take each one

of these prospective curvilinear squares

and turn it back into a square square.

And when I do that,

the composition ends up looking like this.

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[Narrator] Making a full-scale work

would take days to complete.

But Kurt can demonstrate his creative process

on a smaller scale.

This is free-hand drawing and there would almost never

in any case be a trace on the pavement.

The kind of chalk I'm drawing with is a commercial chalk

that you can buy, whereas the other chalks you see

in these different containers are handmade pastels.

I do make them myself.

Nobody makes a pastel where the pigment content is 100%.

I just wanted the colors to be stronger and blend less.

So my pastels are made with pure pigments

which means they're the powdered color,

the oxides or the chemicals that make the color

are the entire content of the pastels,

whereas when you buy a pastel or a chalk,

it's about 30% of the content.

Traditionally, you know, of course every image

is its own thing, but an optimal size

is about 15 feet by 15 feet and that's the size

where you get the most bang from your buck.

So from the point of view of a person standing

at the base of the drawing and, say, taking a photo

which has become the reality at least of this work,

that the image fits just about the right amount

of the camera frame compared to the environment

around the image and other spectators.

People misunderstand the impermanence.

People think you do the work and then it goes away.

But when you're dealing with materials

and situations where the work is impermanent,

it doesn't work that way.

The work is going away while you're doing it,

so it's like building a sandcastle where you get, you know,

a little tower on the left side and you go build a tower

on the right side, and the left one has fallen down.

This is the best possible office anybody could have

when it's this beautiful day when the temperature's nice.

Nothing better than this office,

but it can also be an office where it's rainy,

it's cold, it's windy, or noisy, or unbelievably hot.

When I did this piece during an event,

the pavement was so hot that it was literally burning

the materials I was working with.

[Narrator] Regardless of the challenges,

Kurt brings his pieces to life,

sometimes in a jaw dropping scale.

This was the world record size pavement art,

440 feet long.

One of the interesting geometrical parts of this work

is that the bottom part of the work was done

on the ground at full size.

So while the bottom of the painting,

where the people are standing,

was painted on the pavement itself, on this,

it's actually an airstrip,

the part above where this panoramic part was painted

on a curved panel, much smaller,

which was suspended from scaffolding.

So the shot is a camera shooting through this curved panel

which is cut out here and then seeing

the enormous pavement art underneath

with all the people standing on it,

most of whom were the artists that helped execute this work.

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[Narrator] Kurt's art has always been a consuming passion,

fascinated by how he can plant the extraordinary

in the midst of every day.

How much time have I spent in life thinking about this?

I think I've spent my entire life thinking about this,

starting from when I was eight years old.

I'm 64 years old, so that puts me at well over

half a century that I've been thinking about these problems.

[Interviewer] Is this similar

to how you model your pieces?

Yeah, this is exactly how I model my pieces,

especially before when I was doing them,

before we had photography and Photoshop and all of that.

The drawing is in scale, which means

that these grid lines here, each are one inch by one inch,

they correspond to one foot by one foot in real life.

This little model here is about five and a half inches tall,

as is this one, and then this would tell me

that a person standing with a eye level

of five and a half feet standing here

and a person five and a half feet standing at the back end

of an eight foot by 10 foot image.

This will appear in a certain way with a lens

which is at this particular distance, which we fixed,

and this particular height and is centered

on the pavement surface.

And the iPhone then is gonna tell me,

in the viewfinder, what a person would see.

Now the first thing to do, though, is to get the focal point

in the right place.

So I do this by having these two little towers

and I can move the two towers up to these lines

and position exactly where my lens is gonna be.

So you have to let the camera tell you

where its focal point is by looking at the image

through the lens you're gonna be using.

Eventually somebody would be drawing

or composing in this area, but there's a number of examples

of things they can use in order to see the effect.

So at this point, this effect

of this person standing on this sphere.

So here's the image in the correct position.

And then if I take it and move it this way,

of course, the illusion's going to fold up.

It almost appears like a paper pop-up book

where the the whole thing folds down and becomes flat.

And this way it wouldn't be illusionistic.

It's only gonna be an illusion when it's exactly

in the right position.

[Narrator] This ability to bend reality

with geometry started when Kurt was a young man

with some parental encouragement.

My father saw that I was interested in art.

He was a mathematician and scientist,

so he gave me this little paperback book

called The Geometry of Art and Life.

And this little book described how geometry is used,

both in art and by nature.

And so that book fascinated me.

I had worked for NASA before and had developed certain ways

of doing perspectives to capture very, very wide angle views

of things, especially planets and spacecraft.

When I left my job and started working

on the streets of Rome as a pavement artist,

I started by doing classical works.

After a while, I wanted to do my own original works

and I started to also notice that the works on the pavement

were seen always from the base of the work,

which means people were looking as much across the surface

of the work as they were looking down at the work.

So I decided I could use some of the technology

or the techniques that I used at NASA on the street,

calculating the actual position of the viewer,

and making the work accurate from that position

rather than composing the work

as if it were a wall painting.

It was a little bit strange because the first piece

where I looked at and I said, Oh this is a new art form,

this never existed before, was the Dies Irae piece.

I didn't do a drawing for this piece.

I actually composed it on the street,

painstakingly stretching out all

of the different figures using geometry

and considering each figure separately.

Later on, I figured more of an overall geometrical formula,

which allows me to design the works

on paper, in scale, and then enlarge them.

This piece took me about six weeks to design and finish

and then, in this case, the design and the finish

was on the same spot because I didn't

have preliminary drawings from it.

[Interviewer] Do you do this art

for you or for the public?

That is such a profound question,

is this art for me or for the public?

That's a question that could actually be applied to all art.

In some way, I think artists are always expecting

that they're communicating with other people.

This is an art form which grew up as a communication tool.

It grew up as a way to engage the public.

The beauty of the work is to consider the environment,

the spectators, the public, the point of view of the viewer,

and to compose a work which creates a relationship

between all those three elements.

[upbeat hip hop music]