Medieval Crate

Crate as seen in UDK (back and front)

I was working on the diffuse map last week but something was just not right with it, when I started to think of and work on the other maps I came to realise that the fault I had probably made was that I was trying to do the work of the normal and specular maps because I wanted it to look complete and finished.

A diffuse map should only hold the basic colour and not any lighting or surface details; I think I was trying to do too much with it just because I was eager to see how it would look when it was done. I fixed this by decreasing the contrast of the metal parts and making the edges look more worn rather than shiny and polished.

Previous diffuse on top, new one in the bottom

A specular map is used to tell the game engine how different parts of the metal should reflect the light, meaning how shiny things are. When creating a specular map one should keep in mind what materials their model would be made from and how they react to light. In my case the wood would not be very shiny at all and therefore needs to be very dark in the specular map. The metal on the other hand needs to be shiny, but the surface of my metal is quite rough, implying that it was handmade with crude materials and tools in the medieval times, so it should not be super shiny as it would be if it had been polished. I also have two kinds of metals so the darker one that is used on the corners are not as reflective as the lighter metal used on the rest of the crate.

How an object is used and how old it is are also aspects that need to be taken into consideration with all the maps. Since my crate is contemporary, used often by its owner and has been around for a while the edges should be worn, as I drew on the diffuse map, and therefore polished and shinier than the rest of the metal.

Highlights and shininess could be added to the model through the diffuse maps, but by using specular maps the models will be affected by the light in the game in real time. This makes the models very much more diverse, as they can be placed anywhere in the game instead of needing a fixed place where it only looks good if looking from the right angle.

Specular map

The normal map is used to create surface details to keep the polycount down on the model itself.  I used it to create the rough surface on the metal parts of my crate and to add veins in the wood and gaps between the planks. If I were not using a normal map I would have been right when dong my first diffuse map, but it is unnecessary as the normal map gives so much more depth.  

I started with a black and white version of my diffuse map, quite similar to the specular map as the darker parts will be deeper and the lighter part will be sticking out. I did decrease the contrast both in the wood and (mostly) the metal to get a smoother surface. Then I tried to think of at what depth each part should be so that it would look even and right, for instance I made the gaps between the planks very dark so that they would be clearly visible to fit the medieval look.

Everything that does not change the silhouette of the model should be created with normal maps as it can minimize the polycount dramatically, meaning less pressure on the game engine and memory space.

Normal map

Crate as seen in 3DS Max