Wavefront OBJ
参考
- 类别
导入 - 导出
- 菜单
OBJ is a widely used de facto standard in the 3D industry. The OBJ format is a popular plain text format, however, it has only basic geometry and material support.
Mesh: vertices, faces, edges, normals, UVs
Separation by groups/objects
Materials/textures
NURBS curves and surfaces
Note
There is no support for mesh Color Attributes, armatures, animation, lights, cameras, empty objects, parenting, or transformations.
Note
Blender now only supports complex node-based shading. OBJ having a fixed pipeline-like support of materials, this add-on uses the generic wrapper featured by Blender to convert between both.
Warning
Importing very large OBJ-files (over a few 100mb), can use a lot of RAM.
用法
Import geometry and curves to the OBJ format.
如果有与OBJ匹配的 .MTL 文件，那它的材质也会被导入。
属性
导入
包括
- 图像查找
This enables a recursive file search if an image file can't be found.
- 平滑组 Smooth Groups
Surround OBJ smooth groups by sharp edges. Note that these will only be displayed when the Edge Split modifier is enabled.
- 行数(线)
Import OBJ lines and two-sided faces as mesh edges.
变换
- Clamp Size
OBJ文件的比例通常差别很大，此设置会将导入的文件固定为固定大小。
- 向前/向上轴
由于许多应用程序使用不同的“向上”轴，因此存在转换轴向设置，向前和向上轴——通过映射不同的轴，您可以转换应用程序默认的向上和向前轴之间的旋转。
Blender使用Y轴向前，Z轴向上(因为前视图沿+Y轴方向)。 例如，许多应用程序通常使用Y作为向上轴，在这种情况下，需要使用-Z轴向前，Y轴向上。
几何数据(Geometry)
- Split/Keep Vertex Order
When importing an OBJ it's useful to split up the objects into Blender objects, named according to the OBJ-file. However, this splitting loses the vertex order which is needed when using OBJ-files as morph targets.It also loses any vertices that are not connected to a face or edge so this must be disabled if you want to keep the vertex order and loose vertices.
- Split by Object & Split by Group
When importing an OBJ it's useful to split up the objects into Blender objects, named according to the OBJ-file. However, this splitting loses the vertex order which is needed when using OBJ-files as morph targets. It also loses any vertices that are not connected to a face, so this must be disabled if you want to keep the vertex order.
As far as Blender is concerned OBJ Objects and Groups are no difference, since they are just two levels of separation, the OBJ groups are not equivalent to Blender groups, so both can optionally be used for splitting.
OBJ Export
Exporting OBJ-files is built into Blender without the need of an add-on. It's documentation can be found here: OBJ Exporter </files/import_export/obj>.
兼容性
缺失
Some of the following features are missing:
Advanced Material Settings -- There are material options documented but very few files use them and there are few examples available.
Normals -- Blender ignores normals from imported files, recalculating them based on the geometry.