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In Blender they speak about the UV/Image Editor. I cannot find the meaning of the letters "UV". What is UV standing for ?

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Since 3D space and texture coordinates are stored together with the mesh to distinguish between them texture coordinates are associated with a separate letters sequence (U, V and W)

U and V denote the X and Y axes of the 2D texture that is projected onto the 3D model. 3D generated textures have another coordinate W that is equivalent to Z

Denis
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    is there any meaning associated with the letters U and V or is it just that they stand for X and Y axis ? –  Aug 23 '15 at 18:09
  • No, its just a sequence of letters to distinguish texture space from 3D space, since texture coordinates are stored together with the mesh. – Denis Aug 23 '15 at 18:16
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    But then you also have W,X,Y,Z for quaternion rotations, so it's somewhat misleading unless you know the context of the axis. As far as I understand it, UV was just the arbitrary designation of texture space when the concept was created. – Italic_ Aug 24 '15 at 04:44
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    It's just the three letters that come before X, Y and Z in the alphabet. – AndreKR Aug 24 '15 at 05:35
  • I think this is an amazingly uncovered area of Blender. Lot's of tutorials show how to use textures; however they'll often cover specific answers for certain activities. I know I would like to understand this a lot better! :-) The Related Questions to the right have little detail related to UV. I've seen complex tutorials using UV and nodes, and still fail to grasp some underlying structure about the data and nodes. Perhaps this or another question could be expanded to include the UV relationship via the mesh, nodes and images. Please include link. – Cyberchipz Aug 26 '15 at 22:18
  • @Cyberchipz you can ask a separate question, that will be easier for other users to find a specific answer. – Denis Aug 26 '15 at 22:22
  • @Denis, I've been meaning to ask, doesn't my rep get lower when I ask a question? – Cyberchipz Aug 26 '15 at 22:23
  • @Cyberchipz If you ask a good question people will vote for it, and each upvote will give you 5 rep. – Denis Aug 26 '15 at 22:24
  • The W in UVW also conflicts with the W in XYZW homogeneous coordinates, also known as "that thing you do where you have 4-vectors for points in 3d space so you can multiply them through 4x4 matrices, and related deep magic". Just a unfortunate side-effect of growing systems arbitrarily assigned. Did anyone even think that 3d textures would exist when UV was drummed up? (Hell, did it even come from texturing in the first place?) – Weaver Mar 03 '17 at 11:44
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U V and W co-ordinates are the same as X Y and Z co-ordinates except U V and W are used to describe the co-ordinates of a MESH while X Y and Z describe the co-ordinates of Z-SPACE. but, the UV editor is only 2D so the W co-ordinate is not seen leaving just the U and V co-ordinates, hence the UV editor. -Noah

Noah
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    I'd like to see more details in this answer; obviously there's a concept regarding the use of textures that, for myself, once understood could facilitate a concept in Blender's use that would improve my ability to use the texture system, as that and the nodes seem related, especially as it relates to the data output and others. – Cyberchipz Aug 26 '15 at 22:11
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Let me begin with the wrong answer for what UV mapping is... Imagine we want to use a photograph of a real cereal box and line it up on our virtual cereal box so that it can be applied to the surface. With a camera, we might capture three sides of the cereal box. Now imagine a dot, positioned on the photograph where those three sides of the box come together. Our goal is to get that dot from the photograph, to line up at the correct corner of our virtual cereal box.

The correct answer is to do the above backwards, except, one dot won't do it. UV mapping is the process of placing all the "dots" from our virtual box onto a photograph. Since a 3D model is made from a collection vertices, we let each vertex represent a dot, and then place those dots on the photograph where they belong. We let the computer distort the photograph, as necessary, so that those dots match up with their associated vertices.

Each triangle in our 3D model is represented by three vertices. Each triangle is filled in by distoring the pixels from the photograph, that are associated with that triangle, as defined by "dots" we laid on the photograph from our 3D model.

WynnSmith
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