Registering renderer doesn't work in batch mode

[eliang]

Hi,

I'm writing a software renderer in Maya.
Before doing anything serious, I want to try something easy first.
I registered "Another Renderer" described in the following page:

http://download.autodesk.com/us/maya/2011help/Commands/renderer.html
(see the example at the bottom of the page)

It works if I do the regular single-frame rendering.
But when it comes to batch render, nothing happened,
and then in the render log it says:

Error: The renderer anotherRenderer is not registered yet.

The strange thing is,
Another Renderer is registered with a batchRenderProcedure.
Doesn't that make the renderer support batch render?

Thanks! 

[joojaa]

But when it comes to batch render, nothing happened,

Its not enough to actually call thsi command once you need to call it every time maya starts. The batch render is NOT the same maya as the one your using so it need to have the registration done at startup, otherwise it has no idea that the renderr is registered (maya will forget any registration on shutdown.)

So if you just run the example then ist not a persistent change. It will work in one session thats it. But yes it DOES work in batch mode just as long as you declare the rgistration somewhere where it counts. Theres just a few other things it needs aswell as just this one to get it working properly.

[eliang]

Thanks for your tip.

I managed to figure out how batch renderer works in Maya, finally.
It took me quite a while to get to know this mechanism, so I guess it would be useful for somebody else.

By clicking Batch Render in the menu, Maya spawns another process that executes Render executable (in Windows it's maya_dir/bin/Render.exe).
Render.exe takes an argument "-r" for a renderer name.
The renderer name is nothing special.
It is only a string for Render.exe to find the XML file that describes the renderer.
You can see those XML files in maya_dir/bin/rendererDesc.
Besides listing arguments the renderer provides, the XML file also contains MEL scripts to do the actual rendering.

For example, in command prompt if you execute:

Render.exe -r myCustom

Render.exe will try to read myCustomRenderer.xml. If it exists, the MEL in it will be executed.

Because Render.exe is another Maya process independent to the original Maya that spawns it, it is necessary to register the renderer (using "renderer" command) and load the required plugins (if any) for Render.exe again.
All these commands should be put into the XML file for the custom renderer.

You will also need Maya to execute Render.exe with the right renderer name.
This is done by -batchRenderOptionsStringProcedure flag of "renderer" command.
Pass it a function which returns a string like this:

global proc string myBatchRenderOptionsString()
{
return " -r myCustomRenderer ";
}
The returned string will be appended when executing Renderer.exe.

There's some other info here:
http://usa.autodesk.com/adsk/servlet/ps/dl/item?linkID=9242258&id=13376545&siteID=123112