Before we get to Blender UV mapping and what it is, we need to know a bit about texturing. In the previous post, we learnt how to create Cycles shaders.
You would have played around with different colors for your diffuse shaders, glossy shaders, or whatever to make it look more interesting. Apart from just changing colors, you can use textures. These should be really obvious what they do. For example, if you choose Brick Texture, then you will get a brick like texture on your 3D models.
These textures are called Procedural Textures except the Image Texture. In other words, these textures will look good and consistent from any angle as long as you set it up right. Procedural Textures are basically computer-generated textures. Adding image textures instead of procedural textures tend to make your 3D models look a lot more appealing and just well, better. The below image shows a procedural brick texture left and a real-world image texture of a brick right applied to a mesh. Clearly, the real-world image texture will look better on your 3D models than the procedural one.
But how do you define where the image texture maps to your 3D models. And you want to add a tattoo on his arm. A computer cannot generate a tattoo. Actually, it might if you use some complex algorithm but what I mean is, you probably want to design the tattoo yourself using Photoshop or GIMP or something. Secondly, it will be difficult to tell the computer to put the tattoo specifically on the arm and nowhere else. Procedural textures tend to distribute the texture all over the model.
So if you want to define or paint your 3D models, you need to use image textures. You would need to do this mapping by yourself. This process is called UV unwrapping in Blender. The idea is that the vertices, faces and edges coordinates will be arranged in a 2D mapping grid. When you place your own image on top of the 2D grid, the coordinates in the grid containing the image will copy over the image to the corresponding coordinates on the 3D model.
That was a bit difficult to explain. Here is a simpler explanation. Think of it like your 3D object wearing a full body suit. That suit is then squashed and arranged in a way that you can paint on it like a canvas.
Sometimes you would cut pieces of the suit that are a bit difficult to paint on and put it on another vacant part of the canvas. There are various types of Blender UV mapping options available.UV mapping is a technique used to "wrap" a 2D image texture onto a 3D mesh. For example: increasing your "V" on a sphere might move you along a longitude line north or southwhile increasing your "U" might move you along a line of latitude east or west. Another explanation can be gleaned from the Blender manual.
Imagine a paper 3D model of an object, e. Each of the 3D coordinates of the sphere can be mapped to the 2D coordinate on the flat piece of paper.
You can select and edit these 2D vertices just like in the 3D Editor window. We'll use a sphere for this demonstration. Leave the settings at default for now.
The definitive tutorial to UV mapping in Blender
In edit mode, select a ring of vertices around the widest part of the sphere the equator, if you will. This tells the UV unwrapper to cut the mesh along these edges. Next, create a window for the UV mapping: click and drag left the small lined area in the top right corner of the 3D window, a new window will be created. Now we're going to actually use this UV map. Then with the grab, rotate and scale tools, adjust the UV islands the UV groups that aren't connected to each other so that it fits nicely on top of the image as shown.
Note: Since the aspect ratio of the image will warp the UV's, it may be easier to simply re-unwrap the mesh exactly the same way you did before. You can then adjust the UV's as needed. If you have issues fitting to the image use X and Y letters after pressing S. This will adjust the shape to fit the image.
Back in the 3D View window, go into Object mode. The next drop-down menu to the right of the mode menu is the Viewport Shading Draw Type menu; use it to set the Viewport Shading to Texture. Note that parts of the model will be shadowed and other parts illuminated based on the location of the lights in your scene. Try adding more lights and moving them around so you see the model more clearly, and try to use this lighting preview to 'Rough' your lights.
Blender UV Mapping Complete Beginner Tutorial
To make the texture visible in renderings, you also need to add the texture to the sphere as a new material. In the Properties window, switch to the Material context by clicking the small shaded-sphere button. Create a new material by pressing the New button, leave the settings as they are for now; then switch to the Texture context. Create a new texture and select the type to be 'Image or Movie'. Select the globe texture from the dropdown menu. This will make use of the UV's we unwrapped earlier.
To make the globe a bit smoother, switch to the Modifier context in the Properties window and add a subsurf modifier; set the number of subdivisions to 2. This will make the globe far smoother and more realistic. Note that in the above render I've changed the lighting and the camera position to make the image more interesting.
I also added a star background, you can find the settings for this in the World context a pretty relevant coincidence in the Properties window and the texture settings for the World. Go to Texture settings and if you weren't already there, click on the World texture settings upper left globe icon and set the type to Voronoi.
Scroll down to Colors panel and check Ramp and give Color Stop 0 a white color and an alpha of 1 and Color Stop 1 a black color and alpha of 0. That will do the trick. In some older versions there was a standard option for this but it has "disappeared". If you looked around the textured globe we just made, you would have noticed that around the 'equator' there were lines, or 'seams', where the two UV islands met.
This is a common problem with UV mapping and there are a couple of ways to avoid it. In our case, since we're using a sphere, the best way to remove the seams is to use spherical mapping.
Then use this texture for your globe instead of the one we first downloaded.Blender offers several ways of mapping UVs. The more advanced methods can be used with more complex models, and have more specific uses. Result of unwrapping Suzanne. Flattens the mesh surface by cutting along seams.
Useful for organic shapes. Begin by selecting all faces to be unwrapped in the 3D View. With our faces selected, it is now time to unwrap them. This method will unwrap all of the faces and reset previous work. If all faces of an object are selected, then each face is mapped to some portion of the image.
Blender has two ways of calculating the unwrapping. They can be selected in the tool setting in the tool panel in the 3D View. This usually gives a less accurate UV mapping than Angle Based, but works better for simpler objects.
Activating Fill Holes will prevent overlapping from occurring and better represent any holes in the UV regions. Also, portions of the same image can be shared by multiple faces.
A face can be mapped to less and less of the total image. Smart UV project on a cube. Smart UV Project, previously called the Archimapper cuts the mesh based on an angle threshold angular changes in your mesh.
This gives you fine control over how automatic seams are be created. It is good method for simple and complex geometric forms, such as mechanical objects or architecture. This algorithm examines the shape of your object, the faces selected and their relation to one another, and creates a UV map based on this information and settings that you supply.
In the example to the right, the Smart Mapper mapped all of the faces of a cube to a neat arrangement of three sides on top, three sides on the bottom, for all six sides of the cube to fit squarely, just like the faces of the cube. For more complex mechanical objects, this tool can very quickly and easily create a very logical and straightforward UV layout for you. The Adjust Last Operation panel allows fine control over how the mesh is unwrapped:.
This controls how faces are grouped: a higher limit will lead to many small groups but less distortion, while a lower limit will create fewer groups at the expense of more distortion. This controls how closely the UV islands are packed together. A higher number will add more space in between islands. Lightmaps are used primarily in gaming contexts, where lighting information is baked onto texture maps, when it is essential to utilize as much UV space as possible.
It can also work on several meshes at once. It has several options that appear in the Toolbar:. You can set the tool to map just Selected Faces or All Faces if working with a single mesh.
The Selected Mesh Object option works on multiple meshes. To use this, in Object Mode select several mesh objects, then go into Edit Mode and activate the tool.
This is useful if mapping more than one mesh. If mapping multiple meshes, this option creates a new UV map for each mesh. See UV Maps. The Follow Active Quads tool takes the selected faces and lays them out by following continuous face loops, even if the mesh face is irregularly-shaped.
Note that it does not respect the image size, so you may have to scale them all down a bit to fit the image area. Please note that it is the shape of the active quad in UV space that is being followed, not its shape in 3D space.
It only takes a minute to sign up. Is it possible to turn this generated mapping into an UV Map? If not, would it be possible to access the generated mapping by using bpy? Generated coordinates are based on the 3-dimensional bounding box of the mesh. For more on texture coordinates see my explanation of texture coordinates here. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Asked 4 years, 8 months ago.
Active 4 years, 8 months ago. Viewed 2k times. Active Oldest Votes. However, you can recreate the U and V generated coordinates in a UV map. This will result in the same U an V coordinates as generated mapping. PGmath PGmath So the code to compute this should be somewhere in blender. And since with cycle with it's "Vector" input allows way more complicated mappings, it would be nice to bake these back to UVs. Is there really no way? Mar 29 at Sign up or log in Sign up using Google.
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Feedback on Q2 Community Roadmap. Linked Related 4. Hot Network Questions.Discussed in the previous sections of the Learning Blender 3D tutorial series were Blenders general layout and basic keyboard and mouse controls. We then put those to use going through the process of making an actual chair that then had a material assigned to it. These steps give us a basic object ready for the next part of the process of applying texture images to the mesh so it looks like its made of something, - "wood", "stone", "metal", etc.
For this we need to turn our attention to something called " UVW mapping " or " UVW unwrapping "; its an essential part of producing fully functional models that can be used within game or interactive environments, so they need to be understood, what they are and how they are used. Imagine covering a table with a large piece of cloth, unfolding and shifting it around so it covers the entire surface. The 'cloth', or more correctly how the cloth is positionedequates to the UVW data of a 3D object, the actual process of working out how the cloth is positionedis the 'unwrapping' of a model, both being part of the overall procedure of making sure the cloth lays on the table correctly and the texture image over the mesh without gaps or exposed areas.
So, a " UVW map " is essentially a set of co-ordinates Blender and other 3D applications use to tell them how a texture image is supposed to be applied over the surfaces of a model, so the data itself is called the "map". The process of working out this UVW data and how a texture image should be positioned or placed on a mesh object is typically referred to as " UVW mapping ", " UVW unwrapping ", " UV mapping " or just " unwrapping ".
At this point the chair model should look similar to the image shown below, it has a single global material applied that's composed of individual " Material ", " Texture " and " Image " slots. Progress so far. Continuation of making a chair in Blender after adding a material, a texture and an image. For reasons of being pragmatic it's a good idea to have the UVW map visible whilst the next couple of steps of the tutorial are carried out.
Selecting all faces " A " will display the entire map typically as a jumble of lines right now, which is the result of cutting and shaping the mesh with this default map in place. This needs to be fixed by correcting the distribution and layout of the UVW map. If the chair doesn't have a UVW map then it's an easy matter to assign one.
In Edit mode select all faces of the mesh " A "press " U " to open the " UV Mapping " pop-up and then select " Unwrap " from the list of options, this will give the object a basic UVW map as a basis from which to work although it will likely be 'messy' at this stage for the same reason mentioned above. Both a default and freshly made UVW map will look like this at this point.
The texture image loaded into the material previous discussed can now be assigned to the mesh. Before doing so to make sure it can be seen in the 3D view, switch from " Solid " to " Textured " shading via the " Viewport Shading " pop-up menu in the Header.
On doing this the mesh will go 'white', both in Object and Edit mode, to indicate the view rendering has changed to "Textured". Although Blender has a number of options available to map the UVW coordinates of an object, the best approach is to use a systems of 'cuts' that determine how the map is unwrapped so it fits the mesh, making the most efficient use of the amount of room available within the confines of the width and height or the assigned texture image - the " texture space " as its more often referred to as.
These cuts, correctly referred to as " Seams ", are specially marked ' edge elements ', tagged so the unwrapping process knows to split the UVW map at these points, creating divisions without the need to physically section the mesh itself into corresponding segments. From the " Mesh Select Mode " menu, select " Edge " from the available options. Before going further however, we need to understand some important principles to do with how seams are placed.
As mentioned above, seams 'cut' the UVW map so it can be laid out flat and efficiently within the bounds of the available texture space.
There are two primary concerns when doing this, that. With the above points in mind this typically means that unwrapping a mesh does not always use the most obvious, simplest or straightforward layout if its to be comply with these two core principles; the idea is to have as contiguous a layout as possible so elements are only split into independent units when absolutely necessary.
For example, the easiest way to map the chair would be to do a " box " or " cube " projection so everything is mapped relative to their respective orientation of " front ", " back ", " top ", " bottom ", " left " and " right ", resulting in six main individual UVW island elements.Join our newsletter and get updates of our news and content as well as our 3D modelling workflow cheat sheet. Artisticrender is supported by its audience.
When you purchase through links on our site, we may earn an affiliate commission. Learn more. UV Mapping is by many considered being the most boring part of the entire 3D art pipeline. A mini game tucked right in the middle like a massive roadblock that does not fit along with all the creativity surrounding it. After having read this article however, I hope that you are one of those people that does not think this way.
But instead appreciate the cool technology. Instead utilize different techniques on different parts. The goal of this article is to cover as much of the unwrapping process as possible for as many workflows as possible.
This is to get a broad understanding of the process and tools. In the end though, we will boil it down to a handful of tools and procedures that can help you get most of the Unwrapping done efficiently and accurately through looking at some common workflows.
UV mapping or UV unwrapping is taking a 3D model and cutting its geometry and lay out the pieces flat on top of an image. We then use the result to map the position of the image to the position on the 3D model.
You may have seen those odd images sometimes that looks like you could print, cut out and glue together to create an origami figure. If you have seen such an image, that is most likely an image custom made to be mapped onto a specific 3D model using a UV Map. Your 3D model has X, Y and Z coordinates. But under the hood a U and V coordinate can also be stored for each of those vertices in your mesh.
These coordinates are the 2D coordinates that is used to map a 2D image to the faces on your 3D object. In Blender we can have multiple sets of U and V coordinates. Each set stored in a separate UV Map. The UV Maps live with the mesh object and the list of UV Maps for a specific object can be found in the properties panel. Go to the mesh data tab and find the UV Map section.
The first scenario is that we already have textures. Most likely seamless textures that we want to map onto our object.Unity can unwrap your Mesh The main graphics primitive of Unity. Meshes make up a large part of your 3D worlds. Unity supports triangulated or Quadrangulated polygon meshes. Nurbs, Nurms, Subdiv surfaces must be converted to polygons.
More info See in Glossary for you to generate lightmap A pre-rendered texture that contains the effects of light sources on static objects in the scene.
Lightmaps are overlaid on top of scene geometry to create the effect of lighting. More info See in Glossary UVs. This generates your lightmap UVs into UV2, if the channel is present.Blender Intermediate UV Unwrapping Tutorial
You can also provide your own UVs for your lightmaps. A good UV set for lightmaps should adhere to the following rules:. It should have a wide enough margin between individual charts. For more information, see documentation on UV overlap feedback. There should be a low difference between the angles in the UV and the angles in the original geometry.
See Angle distortionbelow. There should be a low difference between the relative scale of triangles in the UV and the relative scale of the triangles in the original geometryunless you want some areas to have a bigger lightmap resolution. See Area distortionbelow. To allow filtering, the lightmap contains lighting information in texels near the chart border, so always include some margin between charts to avoid light bleeding when applying the lightmap. The lightmap resolution defines the texel resolution of your lightmaps.
Lightmappers A tool in Unity that bakes lightmaps according to the arrangement of lights and geometry in your scene. More info See in Glossary dilate some chart texels in the lightmap to avoid black edges, so the UV charts of your Mesh need to be at least two full texels apart from each other to avoid light bleeding. Use the Pack Margin setting to ensure you have enough margin between the UV charts of your geometry. In lightmap UV space, the padding between charts need to be at least two full texels in order to avoid UV overlapping and accidental light bleeding.
In this image, the black space represents the space between charts. The following screenshots demonstrate equal resolution, but with different UVs. The first image has a high Angle Errorand the result contains unintended artifacts.
In Meshes with more triangles, angle distortion can significantly distort the shape. In the image below, two spotlights with the same parameters light the sides of a cylinder.