The image below sows the base with the weighted concrete balls on the back. In order to create the box that contains the concrete balls, I first had to create a simple box and convert it to an editable poly. Next I created a segment in the middle of the box. This segment was a slightly smaller square in the centre of the box. I then used the polygon tool to extrude the segment downwards to create the box. Then I created a basic sphere and copied it a number of times to fill the top layer of the box.

Then to complete the base of the model a base was added. In order to get the base to fit the shape of the model correctly, a box was used with a number of lengthways segments that had been added. Then using poly modelling the box was moulded to fit the base of the siege engine. Also the pole that would have been used by the animals to pull the siege engine was added using two boxes and a cylinder.

After the base had been completed I started to build the model of the siege engine upwards. The first thing that was built up was the stairs. This was because the stairs can be the hardest thing to get the correct height, so they still look natural and not too steep. Then to make the stairs look more authentic two beams were added either side.

Then once the stairs were in place I continued to build the frame up using copies of basic boxes that were scaled up or down and rotated into place.

Once the frame had been created I could then create the bride that would drop down onto the wall. The bridge was created by using a simple box as the base and then was copied and rotated for the sides. Then a pyramid was added for the end. Finally the bridge was placed in the correct place and scaled down to fit the size of the model.

Next the counter weights and string was added. In order to create the counter weights I used a number of boxes and then to create the curved edge I used soft selection and curved the edge in. To create the sting a cylinder was used. Next tori were used to make the effect that the string was wrapped round the poll and for the hook that the string was tied to.

Finally the textures were added. Various UVW map settings had to be applied to the texture to fit correctly onto the model and so that the planks of wood move in the correct direction. The string used a plane white texture and the hooks for the string used the architecture and design copper texture. The wood texture was found at:

Like a texture, n.d. Wooden Plank. [image online] Available at: <http://fc08.deviantart.net/fs70/f/2010/265/9/2/wooden_plank_by_like_a_texture-d2z9iqu.jpg> [Accessed 1 March 2012].

The image below shows the completed model of da Vinci’s siege engine.