Yes ! It is very weird. I have enabled export to avoid hidden objects and objects set to not renderable.
In Blender, I have checked before hiding objects, showing every layers and the object doesn't appear !
I have made every object visible, selected and deleted everything to clear all layers. After exporting, the square object is still there in Octane and Octane displays 1 Mesh 4 tris...
I tried with a new file : I had to add one cube to avoid export failure. The Ghost object is not there. So, it seems related to my current real scene...
EDIT : A malfunction with some tools just remember me that this file has originally been created with Blender 2.49b and so probably contains some conversion bugs. I tried to append the whole scene in a new file in order to fix it as i did some time ago for an other bug, but this time, the scene is not imported correctly : objects scales broken, and the building that I am working on is missing !
It is a problem when working on big projects on a long time period... file compatibility after upgrade to new versions.
I think I will have to live with the ghost object if I don't want worse things happening while trying to repair the file !
EDIT : Damned ! It is worse than expected : A ghost object is created for each exported obj and when generating a scatter file, the ghost object is instanced as well as the real object used for instance !
I have to "kill" all these unwanted instanced objects by applying Alpha=0, and they are many !
EDIT : I confirm that it is a Blender version conversion bug : I imported again my building in a new file. This time no more scale trouble and no ghost square, but UV mapped objects are no more textured in Blender 3D view ! Fortunately, textures are still linked and present when loading in Octane, but I will have to fix that in Blender if I want to render the objects in Blender.
French Blender user - CPU : intel Quad QX9650 at 3GHz - 8GB of RAM - Windows 7 Pro 64 bits. Display GPU : GeForce GTX 480 (2 Samsung 2443BW-1920x1600 monitors). External GPUs : two EVGA GTX 580 3GB in a Cubix GPU-Xpander Pro 2. NVidia Driver : 368.22.