In this video Paul McGrade explores bump and displacement maps. Both these types of maps affect the surface of our objects with a texture maps.  Bump maps create the illusion of bumps, divets wrinkles etc without actually changing the actual geometry.  Displacement maps change the actual geometry of an object but require more polygons and rendering time to achieve it's effect.

Running time:  2 mins 44 sec

Knowledge of these concepts is required: The Polygon, Texturing, UV mapping

Bump Map: A bump map uses a greyscale texture map that creates the illusion of bumps, divets or wrinkles etc.  Black and white areas of the texture map fake an effect that causes the bumps to either penetrate or rise from the model.  Bump mapping is great for creating fine detail on models without adding to the polygon count, it's easy to paint bump maps and they are fast to render, but be careful as they don't affect the actual geometry and leave the silohette of a model unchanged.

Displacement Mapping: Displacement maps use a greyscale texture to change the geometry of an object.  Black and white areas cause the actual geometry to move up or down corresponding to their greyscale value, but the maps will only work with high or extremely high polygon counts, so they can be slow to render. These maps can be used for animating effects like an waves of an ocean or applying extreme detail to low resolution meshes that are easy to animate.

Texture Map: A 2d image, like a photo taken from a camera, or image painted in a painting program that can be projected or wrapped around a three dimesional model.  These maps can be used to affect a variety of properties of a model including color, specular, bump, displacement, reflection, ambience and much more. 

Greyscale Map: An image that is made up of black and white and shades of grey. 

Render: The process of calculating a 3d scene so that it draws the image.  Although this can be refered to as real time rendering as used in our 3d views or in computer games, we mostly refer to this as when we hit the render button in a 3d application and the computer takes some time, seconds, minutes or even hours to make all the calculations to display a high quality 3d image.