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UV mapping and unwrapping is the process
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of skinning your 3d object onto a 2d
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surface for texturing if you want your
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image textures to properly project onto
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your mesh this process is very important
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but what does a UV map actually look
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like what does it do well let's go ahead
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and show you simply select your object
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and go into edit mode select your entire
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mesh by pressing a then go to your image
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editor and change it to the UV editor in
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the top left hand corner this is
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basically the same thing as your image
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editor but will display your selections
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current UV map over any image you choose
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for reference it's also got a few extra
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settings specifically for UV editing
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alternatively you can also go to the UV
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editing workspace which will bring you
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to the UV editor automatically as you
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can see our default cube already comes
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unwrapped as do most of our primitive
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meshes this is the UV map of our cube so
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instead of explaining it to you I'm
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going to demonstrate how UV mapping
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works with an image texture all I'm
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gonna do is navigate to a file in my
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file browser and drag it to my shader
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editor as an image texture node you can
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see that our UV editor automatically
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displays the image from our image
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texture node we have selected in the
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shader editor but then why is our cube
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still white well to actually apply this
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image to our shader simply click and
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drag the color output into the base
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color input of our shader node if your
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texture isn't showing up make sure
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you're in luck tab or rendered mode in
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the viewport to understand UVs
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let's go into the UV editor and select
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some faces you can choose a selection
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mode in the UV editor just like you can
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in edit mode in the viewport this will
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allow you to edit the UVs like you would
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a mesh GS and our hotkeys also work the
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same as usual however we also have some
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extra tools in the tool bar to transform
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without hotkeys simply select the
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transform tool as you drag things around
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in the UV editor you'll notice our image
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is distorting a little bit on the cube
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for example we can see that this square
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here is correlated with this square on
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the cube if we simply move it around a
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bit we can also scale everything up to
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repeat the texture across the mesh
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it's important to note that by default
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the UV editor will only show the
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vertices edges and faces you have
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selected in the 3d viewport this also
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helps make it clear which face in the 3d
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viewport correlates to which face in the
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UV editor for example we can go into
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face select mode in the viewport and
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select the face that will isolate the
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corresponding UV face in the UV editor
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however you can also flip this function
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and have the UV editor Drive what face
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you have selected in the viewport to do
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that simply click this opposing arrows
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icon on the very top left of the UV
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editor keep in mind if you don't see all
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the buttons here you can expand the UV
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editor or scroll along the top bar with
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this mode toggled we can now go into
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face select mode in the UV editor and
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select faces in our UV map which will
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then select only the corresponding face
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in the viewport which function you want
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to use is up to you I typically work
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with the default function as it keeps my
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UV editor clean now that we understand
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the UV editor and have an image
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projected onto our cube let's go and
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take a look at the different unwrapping
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algorithms we can use unwrapping refers
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to the process of taking a 3d mesh
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unravelling its faces and lying them out
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on a 2d surface to begin unwrapping you
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simply go up here to the UV menu or
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press you even though our cube is
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already unwrapped these are different
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unwrapped algorithms that we can use
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unwrap is your standard unwrap algorithm
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this simply takes into account what
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seems you have marked which we'll get
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into in a little bit and unwraps your
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mesh accordingly smart UV project is one
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of my favorites and is great for
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unwrapping things quickly and roughly
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like map and follow active quads are
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similar but have their own algorithms
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cube cylinder and sphere projection are
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algorithms most fitted for objects
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similar in shape to the name of the
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algorithm project from view is a very
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powerful tool that essentially takes
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what you see in the viewport and
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flattens it as your UV map this is a
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very basic way of unwrapping your mesh
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and will not hold up from different
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perspectives but can be used selectively
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to great effect project from view
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simply stretches the resulting UV across
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the UV editor I'm gonna demonstrate this
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one real quick so let's go ahead and
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select project from view as you can see
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the image projects pretty well on our
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cube from this perspective however if we
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rotate our perspective you can see that
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the image is now stretched across the
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sides that are perpendicular to our view
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from before that's because as you can
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see in our UV editor there are not
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enough pixels for those faces in the UV
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map now you may have noticed that we
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can't get the original mapping of our
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cube back pressing the unwrap option
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doesn't seem to do anything because our
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cube is already unwrapped so let's go
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over exactly how to use the basic unwrap
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function to do this we need to mark some
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seams seams are the edge loops where you
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specify for blender to cut open your
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mesh when skinning it simply select the
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edge loops you wish to mark or clear
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before clicking each option so let's go
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into edge select mode and select these
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three edges I'm going to do the same
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thing on the other side of the cube then
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I can click mark seem in our unwrap menu
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to mark these edges as where we want to
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cut open the mesh this will make them
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appear slightly redder then I'm gonna go
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ahead and select this edge as well and
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do the same thing now I can select all
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of my measures and select unwrap as you
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can see we have something more similar
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to what we had before in case you don't
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understand why I chose the seams that I
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chose let me walk you through my thought
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process the arms of the cross we see in
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the UV map are these faces here they
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needed to completely detach except for
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one connected edge so I marked seams on
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the three other edges of each of these
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faces then we simply needed to separate
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the head of the Cross from the tail of
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the cross that's what this seam was for
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as you work with your own meshes you'll
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get a feel for what seems to work best
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for you to get the UV map shape you want