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VCD Theory

Rendering.

Enhancing form and depicting surface, texture, materials and cast shadows.

What is rendering?

Get your story straight!

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RENDERING COMMUNICATES FORM AND SURFACE

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An amazing water colour illustration on aircraft by Wilf Hardy, Eagle Annual, 1963.

RENDERING COMMUNICATES texture and materials

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Here's how it's done! A perfect rendering of textures and tones by Robert W Gill, "Rendering with pen and ink",p273,1973, 1984, Thames and Hudson,
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Rendering for form

What is form?

Form is the name given to a 3 dimensional shape. A form can be created by angled lines or shapes but when we draw forms with line alone, they lack reality. Forms in real life are seen with different shades of their base colour as the light falls across their surface.

In this first section we will deal with how to render to enhance form alone.

INTERPRETING A LIGHT SOURCE - part 1

Next we move to representing the real surface of our product. We have to spend some time on rendering both form and surface.
Before we begin shading to enhance the form of a draw object we must be aware of the location and direction of the light source. It is customary to work with a light source positioned above an object. However, in addition, the light source may be in front of the object (our side of the object) or behind. This position will greatly effect the way it is shaded. Before you render, make sure you have a clear idea about where the light source is. Look carefully at the images below. Look carefully also at the way the light source symbol is shown.

LOOK CAREFULLY AT THESE IMAGES FOR THE LOCATION AND EFFECT OF A LIGHT SOURCE

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A light source in front and to the left of the object.

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A light source in front and to the right of the object.

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A light source behind and to the left of the object.

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A light source behind and to the left of the object.

SHADING WITH TONE

The first stage of rendering is to bring a form to life with shading. But what shades will I use?

Consider the image below. I have created 10 steps from white to black. Let's say we give these numbers. Call white 0 and black 10. All the steps in between are 1 - 9. This is your tonal range. You have 10 different tones to use on any black and white illustration.

TONAL GRADUATIONS

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An illustrator's keyboard. 10 evenly spaced tones from white to black.

THREE GEOMETRIC FORMS ENHANCED BY TONE

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A cube's form is enhanced with three flat planes of different tones. Use a light, a medium, and a dark tone.
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A cube's form is enhanced with three flat planes of different tones. Use a light, a medium, and a dark tone.
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A sphere's form is described by the same three tones in an evenly blended gradient in both axis. This is called a 'radial' gradient. In a radial gradient the tones blend in both directions - vertical and horizontal.

Try it for yourself

Look at the three images of geometric forms above. How have the tones been applied? If the cube has a light, a dark and a medium tone, what number tones would you say have been used on each plane?

Which forms use flat planes of tone, which uses blends in one plane (a linear gradient)and which uses a consistent blend in all planes (radial gradient).

Task

Make a line drawing of each of the forms above. Shade them to practice light, medium and dark tones, then  to create smooth gradients.

What sort of pencil should I use?

For each of the rendering exercises use a 2H or HB pencil for the outlines, then shade using a 2B pencil. Keep it sharp to work up to your lines accurately.

Rendering to depict colour with tonal graduations

When we render to enhance form alone we do this without respect to what colour an object is. We have just been  applying light, medium and dark tones to its surface.

There must be more to it? We need to apply tonal graduations with respect to the colour of the object we are rendering.

WHAT COLOUR IS THE BOX?

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Each of these rectangular prisms is rendered with a light, medium and dark tone, but they are all rendered with a slightly different group of three tones. This is done to represent different colours for each form.

TONAL GRADUATIONS in action

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Here is another fabulous water colour illustration of transport vehicles by Wilf Hardy, Eagle Annual, 1963. Can you see how he has rendered the white car and the black rocket with a different range of tones?

Try it for yourself

Task

Make a line drawing of a group of boxes like the one above. (Use 2 point perspective or isometric). Shade them to represent different colours of boxes in the same way as shown. Remember to use light groups of light, medium and dark then dark groups of light, medium and dark tones.

Moving into colour

Now we have an understanding of how to enhance for with tone and how to choose tones correctly to represent colours, let's try it in real colour. Remember, what you have learnt with tone still applies with colour.
In these two fine examples, A Year 11 student has shown the checker board box in two ways. She has developed light, medium and dark tones to represent two different, contrasting colours.

colour as tone

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This example is a fine rendering done to represent two different colours on a cube in black and white. CLC 2008

coloured tones

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This example shows the same cube but in colour. Note how the student has created different 'colours' (actually tones of each colour) to represent the light, medium and dark of each. CLC 2008

Try it for yourself

Task

Your task this time is to represent either a group of boxes (like the ones above) or one box with different colours on it, in colour.

The challenge is to create light, medium and dark tones for each colour.

This is how it is done

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Look at this wonderful rendering of a World War II bomber the 'Mosquito' by Rykyu Watanabe, 1981. Can you see evidence of different groups of tones used to represent different colours? Note the way the black and white stripes wrap around the grey in the main body of the plane.

Try it for yourself

Task
Try drawing an oil barrel (ribbed cylinder) standing up. It will have a linear gradient of light, medium and dark tones across its surface. Colour and shade it to represent three different coloured stripes.
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CREATING SURFACE

HOW REAL CAN it be?

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Rendering surface texture and sheen gives ultimate realism to your work. This amazing watercolour image of a Willie Wagtail is by illustrator Peter Trusler. (Birds of Australian Gardens, Koot, McCulloch, Trusler, Rigby, 1980, p101).

What materials will I need to be able to render?

In Visual Communication Design you will have to be able to render many surfaces - both for your practical work and for the examination at the end of Year 12.

First, learn how to be able to create them in 2d in 'swatches' then move onto 3d examples using the techniques in shading you learnt above.

By the end of your course you will be able to render;

  • soft and hard materials,
  • shiny and matte surfaces,
  • opaque and transparent surfaces.

Let's take them one by one. You need to master all of these.

Soft materials

Cloth, leather/vinyl, plastic, paper.

Hard materials

Wood, metal (chrome, satin), coloured plastic (shiny, satin), brick, concrete.

Transparent materials

Glass and plastic (clear, transluscent [tinted] or transparent).

A 3 step process

Try to work in a systematic order to render consistently.

In most cases rendering any textured surface involves a three step process. This applies to most materials.

This is;

  • Create a base tonal render - without trying to represent the texture of the object. Keep it light, the texture will add tone to your work and darken it,
  • Create the texture. Use lines in directions that make the texture look real,
  • Add further shades or details or highlights with white pencil or paint on a fine brush. (A fourth stage can be to add cast shadows on the ground. We will come to this later).
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Learning hint

Each rendering technique you learn should be based on observational drawing of real objects and their textures. It seldom works to copy the techniques of professional illustrators as you will not be representing textures, you will be representing other people's representations of textures. Your work will lack structure.

However, in saying that, the techniques on this page are not designed to make you an artist, nor to help you create original art work that offers an original perspective on the world. By contrast, the techniques here are meant to help you to make marks that work like symbolic representations of surfaces. They are not true artistic interpretations of life, but short cuts to making your drawings realistic.

RENDERING MATERIALS AND SURFACES

Soft materials

FABRICS

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Here is a close up of the textured fabric chair.
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First, put down your light, medium and dark tones to block in your form.
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Next, go over the form with lines to represent the texture. Finish off with some white painted details.

Corduroy and leather

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Here is a rendering I did with coloured pencils of corduroy boots. Note that with this kind of finish their are no deep shades or bright highlights.
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Here is a marker rendering I did of a pair of shiny black leather boots. I worked it up with greys, leaving gaps for the paper to show through. Finally I finished with some white paint. Note on shiny surfaces you get real deep shadows and very bright highlights.

Try it for yourself

Task
Make a line drawing of your school bag. Render it with colour pencils to show the form and colour of its soft surface. Work hard to produce just the right amount of light and shade.

Hard materials

Wood

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To make killer wood grain. Draw your box in isometric. First, put down your base tones; light, medium and dark. As an extension, I made different 'planks' slightly different shades of my base colour.
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Next, go over the form with lines to represent the texture. Finish off with some really sharp dark lines to emphasise the boards.
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Make up a stack of boxes in isometric or 2 point perspective. Render them to show shiny and matte surfaces.

Shiny, satin and matte surfaces

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I included this photo of a 'Knife man' knife holder to show you how satin steel and gloss plastic shine differently.
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Here is a pencil rendering over a freehand 2 point perspective drawing of Lego blocks. Note, I tried to shown reflections on the shiny surface. I finished off with some thin white paint lines. Can you pick them out?
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Here is a quick computer rendering showing the difference between satin and shiny metal. The best thing you can do is look at real surfaces and try to render them.

A SURFACE SAMPLER

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Try making one of these sampler pages before you go into an exam. This is your best training.

Metals

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Here is the famous 'Hot Bertha' kettle by Phillipe Stark. It is made from satin plastic and aluminium. Try to render these textures.
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Try something really shiny for a challenge.
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I did it in Copic markers. Note: it is the reflections that we really draw.

Try it for yourself

Task
Seriously, the best thing is to practice rendering from life. Go around your house and choose one of each of the surfaces in this section then make a surface sampler page like the one above. You can never be sure which ones you will be required to represent in an exam.

Transparent materials

Glass

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Here is a simple computer rendering showing glass.(CLC 2008)
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Here is a nice computer rendering by Mariana Velo Year 11. Note the shines and transparency treatments.
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cast shadows

INTERPRETING A LIGHT SOURCE - part 2

Before we begin rendering shadows cast from object we must be aware of the location and direction of the light source. It is customary to work with a light source positioned above an object. However, in addition, the light source may be in front of the object (our side of the object) or behind. This position will greatly effect the way it is shaded. Before you render, make sure you have a clear idea about where the light source is. Look carefully at the images below. Look carefully also, at the way the light source symbol is shown.

The difference in this section is that the cast shadow will be shown.

LOOK CAREFULLY AT THESE IMAGES FOR THE LOCATION AND EFFECT OF A LIGHT SOURCE

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A light source in front and to the left of the object.

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A light source in front and to the right of the object.

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A light source behind and to the left of the object.

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A light source behind and to the left of the object.

HOW TO MAKE CAST SHADOWS

There are two terms used when describing shading on rendering. We need to be clear about the difference between them. Here's an explanation;

  1. Create shade to emphasise the form of an object = make gradients in tone on (and only on) the surface of the object. Just describe the light as it falls over the object's surface.
  2. Render or create cast shadows = create a transluscent shade (light grey you can sort of see through) that results from the light passing over, either protrusions on the object or the object itself, and are drawn either on the object or the ground.

The purpose of this section is to discuss number 2 - cast shadows; shade that is cast by objects.

It is a pretty difficult science to work out the precise position of cast shadows in a perspective drawing. If you really, really want to work them out you will need to refer to books on the subject. Alternatively, Google it. Just as there are books on how to construct accurate, measured perspective projections, the same can be done with cast shadows. I will show a simple effective method.

The basic concept

What we need to know as students, is the basic concept of cast shadows. We need to know approximately how and where to draw them and more importantly how to align the sides of the shaded area.

I have constructed a very basic illustration of this process. Read the steps below, then try it for yourself.

Find out more information to try it on more complex examples.

CAST SHADOWS from a box

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A cast shadow formed by a light source and additional Vanishing Points. Look below for details on how.

CREATING CAST SHADOWS - the process

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Follow these steps to create cast shadows on any drawing.

As I said, this is only a simplified version of the process, but if you can gain an understanding of it, you will be able to apply it to any drawing.

Try it for yourself

Task

1 - Make a copy of the box drawing below. Go through the steps to see if they work for you.

2 - Move the light source to a point inside the Old Vanishing Points (this will approximate a light source behid the object with the shadow coming forward) and create the resulting cast shadow.

3 - Move the light source up and down, see what causes the shadow to be longer or shorter.

4- Try it on a more complex sketched object like a car.

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Media for rendering

WHAT CAN WE USE TO CREATE SURFACE TEXTURE AND SHADE?

When we talk about media for rendering we are talking about what we use to make the marks that represent texture and/ or shade. There is a wide range of media available for this job. We need to consider what will be the purpose of our rendering and what aesthetic effect are we trying to achieve? Do we want it to look soft warm and friendly - let's sketch in pencil. Or harsh, clear and corporate - let's do it in a computer program like Adobe Illustrator.

Take a look below for a selection of drawing methods and media that can be for rendering.

How it is done

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Great, confident marker work. From "Sketching. Drawing techniques for product designers". Koos Eissen and Roselien Steur, Page One press.

More media

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Colour pencils are our 'go to' for preliminary work and for use in exams.
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Never ever say a Biro won't do! The humble ball point in everyone's pencil case is all you need to beautiful, sensitive tonal work.
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Use pen to create texture when representing old things. Here is a picture of a Ford V8 'Blitz' I used to own.