Working with Maya files

 Working with Maya files

 

modo has the ability to “round trip” a significant amount of Maya data,which is a very powerful function indeed. It is important to remember, however, that with great power comes great responsibility! The Maya I/O utility in modo supports many different Maya nodes. It is important to understand the scope of this functionality so you can structure your Maya data in a way that will avoid modo stripping any unsupported
nodes from your MA file. By leveraging Maya’s ability to reference scene data you can effectively quarantine your mesh data along with
the supported nodes in a separate file so that it can be edited at any time in modo without fear of losing data.

Maya Import
Supported nodes
Meshes

Basic poly mesh nodes are supported. These include vertices, faces, point tweaks, UVs, etc. Nodes that manipulate this geometry are not supported. To ensure that the mesh item contains all of the required data it is best to collapse its history. Limited support is also included for subdivision surfaces. These are converted to a poly mesh on import. Blend shapes are imported with the same limitations. They will be converted to embedded morph maps.

Groups

Locators with no mesh children are imported as empty meshes for hierarchy purposes.

Texturing

Basic texturing information is supported. Imported shaders supported include phong, phongE, lambert, and blinn. This includes "file" node images and "projection" nodes. Texture locators are also supported. Channels supported: color, diffuse, specular, exponent.

Maya Export

Most information in modo will be exported to Maya. This includes the vertices, faces, UVs, hierarchy, texturing, etc. Also, any embedded morph maps will be converted to blend shapes.

Meshes will always be exported to "mesh" nodes in maya. This allows them to be polysmoothed or converted to subdivs.

LightWave Object Import and Export

modo will load and save models in the LWO2 (.lwo) object file format used by LightWave 3D 6.0 and above. modo can also import objects
using the older LWOB object format (also .lwo). LWO2 format files typically contain lists of points, polygons, materials, textures, image
references, vertex maps, etc., all organized into layers.

Images

Image-mapped materials in LWO2 files rely on an external image file whose name is embedded in the LWO2 itself. When loading such a model, modo will try to find these images by looking in the obvious places, such as the last place you loaded an image, the directory the model is in, and whatever else it has in its “search path”. If it cannot find the image, modo will prompt you to find or replace the image. Image references in LWO2 files are commonly stored not with absolute paths to a user's hard disk, but relative to a “content directory”. This helps you share models without having to change or match all the absolute image locations in a model. You can set this directory in the LightWave I/O Preferences panel. When it is set, the LWO2 loader will look there for relative-path images. The LWO2 saver will also write image references relative to this directory when possible.

Shaders and Textures

Shaders and procedural textures can store their settings in LWO2 files. While modo understands a basic set of LightWave-compatible procedural textures, in general this data can only be understood by a specific version of a specific LightWave plug-in, and will be unknown to modo. In this case the textures or shaders are loaded in an “ encapsulated”  form, so their data can preserved and saved with the model, but not edited. The loader will let you know whenever alien data are encapsulated.

modo Extensions

The LWO2 format is readily extensible, and modo extends it to support elements not found in LightWave*. Among the extensions are support for foreground and background layer selections, edge-based weight map values, and modo's native subdivision surface and bezier polygons. 

modo's subdivision surface algorithm differs from that used by LightWave, and can handle polygons which are not quads. To support rendering applications that prefer the LightWave “SubPatch” algorithm, modo lets you work with either its native “Subdiv” algorithm or the SubPatch algorithm, or a mix of the two. If you are using LightWave for rendering, chances are you will want to see your model in SubPatch mode when you load it, work with its limitations (makingsure to only create legal SubPatch polygons), and save it again withSubPatch polys. If some Subdiv polys got in there by accident, you might want them to be glaringly visible as cage polys, or you might want them to try and pass as SubPatch polys. If the destination for your models is not bound by the limitations of the LightWave SubPatch algorithm, you will most likely want to load any old .lwo files with SubPatch polys and convert them immediately to modo Subdiv polys. Either preference is supported under the LightWave I/O Preferences panel. Choose “LdSubPatch as Subdiv” to forget the old algorithm,or leave that option off to preserve the model's compatibility. While the saving preference for Subdiv polygons won't interfere with modo's ability to load these objects correctly, choosing the “Save Subdiv as SubPatch” may create SubPatch polygons with too many vertices for LightWave to handle. Edge-based creasing of subdivision surfaces is also unavailable for SubPatch polygons, so the edge weights themselves must be stored in another extension to the LWO2 file.

*WARNING: While modo-extended objects can be loaded by other applications, it is unlikely that the extensions will be preserved when the other application re-saves the model. Various applications in your modeling pipeline may NOT preserve modo-extensions in .lwo files, so save sensibly.