Joel Gethin Lewis

Lecture 3: Mixing and Sculpting

- Moving from two dimensions to three.
- x,y,z co-ordinates, Pythagoras' theorem in three dimensions.
- R,G,B co-ordinates for colour, other colour spaces.
- Point clouds and voxels.
- Polygons and Polyhedra.
- Bonus: Artists working in three dimensions.

- The third dimension is usually described in terms of a new letter: z.
- The direction and orientation of the three dimensions varies in a similar way to the way the direction of y varies in two dimensions between high school graphs and digital screen co-ordinates, so always check which way is what.
- See how Pythagoras works in three dimensions in this Better Explained article.

- You can map any three variables into three dimensions to help you think about them spatially (i.e. in physical space).
- An example of this is mixing together Red, Green and Blue (RGB) colours to make any other colour.
- Digital colour mixing is additive while analogue paint mixing is subtractive.
- How does projected light mix?
- There are other ways of mixing variables to make colours - for example Hue, Saturation and Brightness (HSB).
- I often use HSB in digital work to make it easy to blend between colours - much easier than RGB. You can visualise colour using a colour wheel or a colour solid. Complementary colours are on opposite sides of the colour wheel.
- Colour theory is a huge area of study, for graphic design and even psychology.

- One way of storing three dimensional information is using point clouds.
- The output of three dimensional scanners is often in point clouds - a grid of positions, each with a depth value - think of Pin Art toys from the 1980's.
- Another way of storing three dimensional data is to use Voxels (from the initial letters of volume and element, with the insertion of -x- for ease of pronunciation).
- Voxels can be a super efficient way of storing three dimension information - used for everything from MRI scanners to Minecraft.

- Another way of storing three dimensional information is using a series of polygons.
- Polygons are geometric objects with at least three straight lines and angles.
- Polygons are plane figures - i.e. they are flat.
- Some examples: squares, triangles and pentagons.
- Triangles are often used in three dimensional software and games - for more information about why this is so see this Computerphile video about A Universe of Triangles.
- A Polyhedron is a three dimensional shape made of multiple polygons.
- The Platonic Solids are a set of three dimensional shapes that have been known about since Ancient Greece and possibly back to Neolithic times.

- Michael Heizer, City.
- Walter De Maria, Lightning Field.
- Donald Judd, Marfa, Texas. "methods should not matter as long as the results create art".
- Nancy Holt, Sun Tunnels.

- More about me: @joelgethinlewis
- Get in contact via: www.joelgethinlewis.com
- Website:

https://jgl.github.io/ComputationalThinking2018 - Today's slides:

https://jgl.github.io/ComputationalThinking2018/lecture3.html