Render layers separate scene geometry into parts, where one part is meant to be visible and the other parts capture the side effects of the visible geometry. The layers allow different Objects to render into separate images where you can apply render passes. The render layers are meant for compositing, not hiding parts of the scene.
Objects can be assigned a specific render layer ID from the Geometry tab in the OctaneRender panel (figure 1). The Live Update button must be checked in order to active the Render Layer parameter.
Figure 1: Activating Live Update and assigning an object a Render Layer ID.
Which render layer that Octane renders can be set from the Setting tab in the OctaneRender panel (figure 2).
Figure 2: Accessing the Render Layer parameters in the OctaneRender panel.
Enable
Activates the Render Layer function.
Active Layer
Determines the layer ID to render. This parameter coincides with the Render Layer parameter assigned to each object in the Geometry tab.
Invert
Inverts the currently selected Active Layer ID.
Mode