Exploring 3D space with a computer – Part 3: building models from plans
Adrian Oldknow
Tower Bridge Model Part 2
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The roof can made from a pair of isosceles triangles, like the pale blue one, and a pair of trapezia, like the brown one. It is topped off with a small isosceles triangle. Once complete we can change the colour of the roof to be more realistic. Note, from a mathematical viewpoint, the main body of the tower has been built up from solid polyhedra - while the roof of the tower is a space enclosed by polygons. |
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| The walkways can also be constructed by defining a polygon (I used a square) on one face of the tower, and using a vector joining the towers to create a prism. The `large hatches' effect conveniently gives the impression of a lattice construction. Then a reflection in a central plane gives the other identical walkway. |  |
| Finally we just need to construct the roadway - preferably in a way that allows it to open like the real thing! We have already used the similar technique to open some barn doors and to fold up the nets of solids - we just need to use a rotation. |  |
| To finish we just need to construct the roadway - preferably in a way that allows it to open like the real thing! We have already used the similar technique to open some barn doors and to fold up the nets of solids - we just need to use a rotation. |  |
You can download the file -
` 
tower-bridge-complete.cg3' or you can manipulate the embedded model on this webpage below.
