Standalone still works best, my opinion. Plugin inside Maya is often good and bad. Maya is always known for being unstable. Previous crash happens on Maya 2010.

On the positive side: (just not to put everyone down)
- Using Maya 2013, using IPR (realtime preview), Octane plugin works brilliantly ...

Fatal Error on this Maya file I am working on ... *sigh*

I think I solved the issue.

1. I set the plugin so it is loaded when Maya start.
2. I still getting error. But this time under preferences, the activation field box is not greyed out.
3. Attempt to put the license. Now it is activate. (I did get error message, but second time works.)

Not very ...

I just purchased license for Maya Octane plugin, but so far didn't manage to get it working. Maya kept on frozen.

// Octane UI is registered...
// Octane scene translator is registered...
// Starting Octane engine...
// Error: Error starting Octane engine: No credentials given. //
// Error: Error ...

Maya Plugin Activation is not so intuitive, I kept getting this error when turning on the plugin:
// Error: Error activate Octane engine: No credentials given.

@matej
That's exactly the best way to put it in context. When things are too physically correct, it's not always artistically correct.

I read another post and matej also answered the same question:
"refractive caustics currently work only with IBL & emitters, not sunlight, I forgot about that"

- J

yeah, the shadow is still black, even when I use pathtracing.

Ok, there are some caustics when using HDRI with "pathtracing" or "pmc" mode.

here is a test render. no caustic on this one, yet. the window hole is a Portal.