UV Mapping vs. Texturing

I was wondering what the pros and cons are for uv mapping versus applying a teure using an image. Maybe what I should be asking is…what is the difference?

Thanks in advance for your help!

Here’s another way to say it …

You already know how a point in 3D space is expressed as “(X,Y,Z).” Each part on the object has such a coordinate.

Now we want to apply a texture of some sort to this object. In order to do that, we need three more coordinates: (U,V,W), where “W” is effectively not used: UV coordinate maps are always flat. Every point on every face of the object can be assigned such a coordinate … which can be anything you want it to be. When you “UV unwrap” an object, what you’re actually doing is assigning what the (U,V) coordinates of each face will be. In the (flat…) UV coordinate space, every (flat…) face will correspond to a (flat…) polygon, located anywhere you’d like it to be (in (flat…) UV space), and oriented in any direction. They can overlap, too, if you wish. (For instance, if you’d like the same feature to show up in several places, just overlap several polygons over the same places on the source UV map where that feature occurs.)

What Blender does with these UV coordinates is to “slurp” image data from the (flat…) images that you’re using as the source of data. Or, in the case of “texture painting,” UV coordinates are also used to designate where the textures should be “sprayed onto” a target map.

So … “texturing” is not the same thing as “UV mapping,” but if you’re going to use a texture, there has to be a UV map (or some “bright-line rule” equivalent to one), because textures are flat and they’re applied to the (flat…) faces of the object based on their (flat…) UV coordinates. (Strictly speaking, you can control this …)

(As an aside, procedural textures don’t have to be flat: they can use 3 coordinate values as their input: X,Y,Z or U,V,W.)

UV mapping simply lets you control exactly where the texture (can be image or procedural, anything) is placed on the model. By default, texture coordinates are set to “Generated” which kinda just uses the object’s coordinates and slaps the texture on from one side. Using UVs allows you to fold the model out flat and lay the texture on there, which wraps nicely in 3D.