As well as working metal, we also need to be able to work in other materials to make the necessary patternwork for production. Some examples are shown here.
Sometimes it is straightforward to make a mould from an existing piece where all the tapers run in the same direction, as in these balusters for a church.
The pieces can be small or large like these patterns for portlights used in the Liverpool Tate.
Or sometimes so large that once made, the pattern has to be cut into pieces to enable casting. This pattern is 3m tall by 1.5m wide and needed to be cast in 10 panels
At the other extreme, sometimes we let nature make the patterns!
Life gets more  complex  when you need to have truly parallel surfaces, for example where an aperture needs to be moulded in, or where some of the shape runs in a different direction. In these cases “cores” are used. These are shapes made from sand which are placed into the mould after the main pattern is extracted. This then modifies the shape which the metal assumes when poured in, allowing undercuts or parallel shapes to be formed. 2 examples are shown here, the black marking indicating where the core is laid into the mould