For example:  I have a Maya 2009 project that needs to work in Maya 2008.  It uses nCloth which was available in 2008 so we are golden there.

• Save the Maya 2009 scene file as a .MA (Maya Ascii file format)
• Open it in any text editor and make sure it’s in plain text format.
• Find the lines of code that reference the Maya version number like this:

//Maya ASCII 2009 scene
//Name: name of maya scene.ma
//Last modified: Sat, Jan 16, 2010 1:12:40 PM
//Codeset: UTF-8
requires maya "2009";

• And simply comment out the lines at the beginning of the file by adding two slashes “//”:

//Maya ASCII 2009 scene
//Name: name of maya scene.ma
//Last modified: Sat, Jan 16, 2010 1:12:40 PM
//Codeset: UTF-8
//requires maya "2009";

There is a new method since the Maya 2008 release (I think that’s when they started this). If you click on File > Open Scene > Option Box, you’ll see a little checkbox to “ignore version“. Much easier this way.

NOTE: If you are using nodes that are exclusive to a new release, this will not work or at least the exclusive nodes will not import.  That will require a little trial and error.

If you are trying to bring locators from Maya into After Effects, or camera data this is a very important tool to have. I especially enjoy the fact that you can simply select any object in Maya, type “pass2obm” and save it to a file.  Once in After Effects you can simply import the OBM file and it populates layers with white locators for each object.  After Effects has the ability to bring in .ma files from Maya, but the nulls have to be named null, and they are imported in as a hidden null object.  The MoCon script works with any naming convention, and creates small solid layers for easy visualization.

Check out 3Dmation here.

Error: File contains unknown nodes or data.  To preserve this information, the current file type cannot be changed.

ls -type unknown;

delete XXXXXX

If someone knows of a simpler method to remove all unknown nodes let me know.