Mental Ray

Is Mental Ray really a slow renderer?

In my opinion it’s a fast renderer. Maybe not fastest on the planet but like all biased renderers you have to fiddle a little bit with the options.
There is an equivalent option in Mental Ray (though more advanced) to the Octree resolution in blender. If you get the right setting there, for the scene, you can speed up the render time a lot.
I rendered a car in XSI in about 8 hours before I figured out how to speed it up. Then I was down to 1,5 hour :yes:

*** Edit1: The setting to tweak for Mental Ray is the BSP tree setting ***
*** Edit2: I found a site with the video that helped me understand how to tweak the BSP tree: http://www.vast.ws/resources/xsi/tutorials/tutorials.html. It’s under “Rendering->BSP Tree->BSP tree tuning setup” ***