Usage_instructions

Once Maya2OSG is installed in your system, to use it, you can follow two different approaches, depending on the situation or your preferences: use it from the Maya GUI or use it from MEL code.

NOTE: There is a known bug in Maya2OSG version 0.1. The exporter ignores the user current selection and exports all the scene. It has been fixed in version 0.2.0. The bug is partially caused as a secondary effect of the scene preprocessing that has been disabled in version 0.2.0.

NOTE: Maya2OSG version 0.2 can cause Maya crashes after several exportations. The problem is in the MEL script, so when you update the software don't forget to replace the MEL scripts in your Maya directory.

• Exporter (maya2osg)
  • Export from the Maya GUI
  • Export from MEL code
  • Scene preprocessing
  • Exporter command-line interface
• Importer (osg2maya)
  • Import from the Maya GUI
  • Import from MEL code
  • Importer command-line interface
• Shelf Buttons

Exporter (maya2osg)

Export from the Maya GUI

1. Select scene elements you want to export.
2. Select OSG tab in the shelf.
3. Push Maya2OSG "Export scene to OSG" button in the shelf.

The first action will be to prepare the scene to be exported. This is can be considered a destructive operation, as it cannot be undone. So maybe it is a good idea to save the scene before exporting it, even though the optimize operations should not cause a major problem, but anyway it is better to prevent, or... do it at your own risk :)

Finally, a file browser let the user select the destination file to export the scene to.

This automated process, in the first releases, loaded the plug-in to use the command and unloaded it after the scene was exported. This is quite interesting for developing, as the plug-in cannot be overwritten while it is loaded. However, Maya does not like this repeated plug-in loading and unloading, and can cause crashes. For this reason, current version only load the plug-in once if it was not previously loaded.

NOTE: From version 0.2.0 the scene preprocessing before exportation has been disabled. For more information about this stage, see the Scene Preprocessing section.

NOTE: A new button is included in the shelf to perform this preprocessing (Cleanup the scene before export). This is currently in SVN and will be included in release 0.3.0.

Export from MEL code

1. Be sure the Maya2OSG plug-in (

   maya2osg.mll
   

) is loaded in Maya.
2. Select the geometry you want to export.
3. Enter the MEL command

    maya2osg

output_path (e.g.

    maya2osg C:/model.osg

).

Scene preprocessing

Before exporting to OSG, the scene should be prepared to avoid potential problems. The recommended sequence of operations is described below:

1. Convert non-polygonal geometry (e.g. NURBS) to polygons.
2. Tessellate objects to eliminate potentially problematic geometry in OpenGL. In the

   Polygons
   

menu select

    Mesh > Cleanup...

. At least you should include the options to fix by tesselation concave faces, faces with holes and non-planar faces. It is also interesting to remove edges with (near) zero length, faces with (near) zero geometry area, and faces sharing all edges.

3. Delete construction history (

    Edit > Delete By Type > History

).
4. Optimize the scene deleting unnecesary elements (

    File > Optimize Scene Size

).
5. Delete static channels (

    Edit > Delete By Type > Static Channels

).
6. Select the elements you want to export. If there is no selection, all the scene will be exported.
Below is the MEL code to perform these operations (steps 2-5) for all the elements in the scene. It is included in the

prepare

function in the

osgexport.mel

script supplied with Maya2OSG in

maya

version

/scripts

directory. But from version 0.2.0 it is disabled. If you want to preprocess the scene automatically every time you push the shelf button, edit the script and uncomment the line "

//  prepare();

" in the procedure

maya2osg_export

(previously

osgexport

) at the end of the script file.

polyCleanupArgList 3 { "1","1","0","1","1","1","1","1","0","1e-005","0","1e-005","0","1e-005","0","-1","0" };
delete -all -constructionHistory;
cleanUpScene 1;
delete -all -staticChannels;

From release 0.3.0 this process will be available in a new button from the shelf (Cleanup scene before export).

Exporter command-line interface

The

maya2osg

MEL command accepts the following parameters:

maya2osg [options] <outputfilename>

Note: Angle brackets

outputfilename

- Output file path

Options:

• -texenv DECAL|MODULATE|BLEND|REPLACE|ADD

- OpenGL TexEnv mode
* -exportDefaultCameras

0|1 - Export default cameras (top, front, side, persp) (default: false)
* -exportOrthoCameras

0|1 - Export orthographic cameras (default: only perspective cameras)
* -surfaceMode SINGLE|DOUBLE|KEEP

- Surface mode (all single sided, all double sided, keep as in Maya)

Importer (osg2maya)

Import from the Maya GUI

1. Select OSG tab in the shelf.
2. Push Maya2OSG "Import scene from OSG" button in the shelf.

A file browser let the user select the input file to import the scene from.

Import from MEL code

1. Be sure the Maya2OSG plug-in (

   maya2osg.mll or maya2osg.so
   

) is loaded in Maya.
2. Enter the MEL command

    osg2maya

input_file (e.g.

    osg2maya C:/model.osg

).

Importer command-line interface

The

osg2maya

MEL command accepts the following parameters:

osg2maya <inputfilename>

Shelf Buttons

TO-DO: Explanation of shelf buttons

• Export scene to OSG
• Import scene from OSG
• Cleanup scene before export
• Preview
• Preview with axes (IMPORTANT: To preview scenes with the axes indicator in the origin,

  axes.osg
  

file must be available in

    OSG_FILE_PATH

).