布局工作流

传递UV贴图

You can copy a UV map from one mesh to another mesh provided both meshes have the same geometry/vertex order. This is useful for example when you want to recreate a UV map from an earlier version of your model with intact UVs. This works by:

1. Select the target mesh (to which you want to copy the UV map).

2. Shift select the source mesh (that contains the intact UV map).

3. Object menu ‣ Make Links… ‣ Transfer UV Layouts (Shortcut: Ctrl-L …).

The target mesh will now have a UV map that matches the original mesh.

多UV贴图

You are not limited to one UV map per mesh. You can have multiple UV maps for parts of the mesh by creating new UV maps. This can be done by clicking the Add button next to UV maps list and unwrapping a different part of the mesh. UV maps always include the whole mesh.

优化UV布局

也许你用的是缝合线展开，展开完成后，UV布局可能相当杂乱无章。那么你接下来的任务就是：UV映射的排列、整理UV映射、将几个UV映射缝合到一起。

下一步是在通过展开流程创建UV布局后继续创作。如果对已经展开的模型添加面或细分现有面，Blender会自动在UV映射中添加面。这种情况下，可以使用UV贴图图像指导对几何体的修改。

在整理时，要记得虽然整个视图都是你的创作空间，但是只有位于栅格中的UV坐标才能映射到图像。所以整理过程中，可以将一些部分移到一旁。另外，每一组UV映射的关联坐标集合都是独立的。

You can lay them on top of one another, and they will onion skin (the bottom one will show through the top one). To move only one though, RMB select one of the UV coordinates, and use Select ‣ Linked UVs, Ctrl-L to select connected UVs, not box select because UVs from both will be selected.

组合UV映射

糟糕的展开，注意耳朵和颈部。

在展开物体时，常常会出现 “多数正确”但部分网格展开不当的问题，就像上面的例子。上面的图片展示了使用球面方式展开脸部的原始结果。问题出在耳朵上，它的UV变成了一坨，还有颈部，拉伸和收缩都很明显。这需要很多工夫来整理。

耳朵和颈部先放一边，仅展开脸部。

We can tell that the ear would unwrap nicely with just a straightforward projection from the side view, and the neck with a tubular unwrap. So, our general approach will be to unwrap different parts of the object (face, ears, and so on) using different unwrap tool, selecting each tool according to which one works best for that part. So let us begin: We select only the “face” faces, unwrap them using the Sphere projection, and scale and rotate them somewhat to fit logically within the image area of the UV Editor.

仅展开耳朵，使用 从视角投影。

Once we are satisfied with the face, it is time to turn our attention to the ear. First, unselect the faces you were working with. Their UVs will disappear from the UV Editor, but they are still there, just not shown. (To verify this, you can select a few faces in 3D View and it will show up in the UV Editor.)

To work on the ear, in the 3D View, we now select only the “ear” faces. You can use vertex groups to select the ear faces. Selecting sub-meshes is easy too, since they are not connected to the rest of the mesh. Simply selecting linked vertices will select that entire submesh. Basically, since you are in Edit Mode, all the selecting/deselecting features are available to you.

Now unwrap the ear again using the Project tool from side view, and scale and rotate them somewhat (discussed in the next section), and place them off to the side. You can do this repetitively, using different unwrapping algorithms; each re-apply just puts those UVs for the selected faces somewhere else. Choose the tool for each part that gives you the best fit and most logical layout for subsequent painting of that part.

When all parts of the mesh have been unwrapped using the various methods, you should end up with something that looks like the example to the right. All sections of the mesh have been mapped, and all those maps are laid out in the same UV texture map. Congratulations! From here, it is a simple matter of “stitching” (discussed in the next section) to construct the entire UV map as a single map.

整理后和缝合后的UV映射。

When you have completed arranging and stitching, you will end up with a consolidated UV map, like that shown to the right, arranged such that a single image will cover, or paint, all of the mesh that needs detailed painting. All the detailed instructions on how to do this are contained in the next section. The point of this paragraph is to show you the ultimate goal. Note that the mesh shown is Mirrored along the Z axis, so the right side of the face is virtual; it is an exact copy of the right, so only one set of UVs actually exist. (If more realism is desired, the Mirror Modifier would be applied, resulting in a physical mirror and a complete head. You could then make both side physically different by editing one side and not the other. Unwrapping would produce a full set of UVs (for each side) and painting could thus be different for each side of the face, which is more realistic).

Iteration & Refinement

At least for common people, we just do not “get it right the first time.” It takes building on an idea and iterating our creative process until we reach that magical milestone called “Done”. In software development, this is called the ‘spiral methodology’.

Applied to computer graphics, we cycle between modeling, texturing, animating, and then back to making some modifications to mesh, UV mapping, tweaking the animation, adding a bone or two, finding out we need a few more faces, so back to modeling, etc. We continue going round and round like this until we either run out of time, money, or patience, or, in some rare cases, are actually happy with our results.

改进布局

当看着我们的角色，然后意识到某个点需要更多细节的时候，改进流程就派上用场了。比如，要在眼睛周围添加一些鱼尾纹，或者在马甲上加个logo。当你开始修改图片的时候，才意识到没有足够的像素点容纳你想要的细节。

Your only choice is to expand the size (scale out) that UV face. Using the Minimize Stretch or Scale tools, you expand the UV faces around the eyes or chest, allocating more pixels to those areas, but at the same time taking away pixels (detail) from something else, like the back of the head. After refining the UV map, you then edit the image so that it looks right and contains the details you want.

重复利用贴图

另外需要考虑的就是节约资源。每张图像文件都会被加载到内存里。如果可以对不同的网格重复使用同一张图像，就可以节约内存。所以，比如，可以绘制一个通用的脸部，然后用在不同的角色上，通过调整UV映射和形状以及道具(墨镜)来加以区别。

You might want to have a “faded blue jeans” texture, and unwrap just the legs of characters to use that image. It would be good to have a generic skin image, and use that for character’s hands, feet, arms, legs, and neck. When modeling a fantasy sword, a small image for a piece of the sword blade would suffice, and you would Reset Unwrap the sword faces to reuse that image down the length of the blade.