Normal mapping (also known as Dot3 bump mapping) is a type of texturing that allows you to imply that there are bumps and dents on the object where in reality these were not modelled in and are just on the texture. Because the bumps and dents are only on the texture, normal mapping allows people to add detail to models without adding extra polygons- this is especially useful with low poly modelling.
Bump mapping adds bumps and wrinkles on the surface of models (normal mapping is a type of bump mapping). The result of bump mapping is a bumpy looking surface on a model while its original smooth surface remains.
While normal mapping adds detail to models without any polygons needing to be added to their original mesh, displacement mapping gives the illusion that a model is more 3D than it actually is.
Above shows the original mesh, the texture then the model and texture combined. While the model by itself is completely flat, adding the texture makes the model 3D. While normal mapping does not change the models geometry, displacement mapping does.
Texturing a Crate using Normal Maps
After learning about different bump maps we were then tasked with creating a crate and texturing with a normal map all within MAYA. To do this I created the silhouette of my create (the low poly model of my crate, on the right in the image below) before duplicating this and adding many more details (the high poly model of my crate, on the left in the image below).
We then went to an option in the rendering mode in the lighting/shading tab called transfer maps and changed settings to something that would suit this crate before baking the texture onto the low poly model. This is what the final low poly model looked like with the normal map on:
This is still the low poly model (made of 30 polys) but the normal map texture has made it look much more complex and detailed. Here is my low poly model next to my high poly model:
Normal mapping was not as complex as I thought it would be and (for this crate) it was pretty simple.