Fisheye question / Exclude object from render element

[Prettysimple]

Hello Corona users,

So here is my problem ; to simulate a fisheye effect I had to turn my camera 180 degrees and shoot a sphere with a perfect chrome material, the thing is that in my pipeline at work I need to extract several passes such as ID masks, Ambient occlusion, reflection, etc, but with this technique even though the elements work as intended I cannot get my passes because the camera just shoots the sphere and it will show only one ID, no ao, etc...

So I was wondering if it's possible to keep the material of specific objects in the render elements, this way I could just "exclude" my sphere and it will still be chrome (similar to what we can do in material override), it would reflect what's going on with the render elements and voilà.

Another way would be to achieve the fisheye effect through corona settings or physical camera but I didn't find any way to do so. I'm not sure what the "lens distortion" panel in the physical camera does, but it didn't seem to change anything for me at least.

Even though I found a solution for the ID's this time (material override of a multi/sub-object material from 1 to 6 which are basic colors (with my sphere excluded from the override) and overexposed lighting) it would be very useful to have a proper solution for this because tight deadlines won't allow me to do this workaround everytime and I still can't have other passes.


I hope you guys can help me with this, thank you !

Edit : I forgot to mention that I need to get the fisheye effect in the render and not in post production :)

[romullus]

Not all features of physical camera are supported by Corona yet. Distortion is among not supported ones.
Most flexible way to get fisheye distortion, would be to render equirectangular projection (not necessary full 360) and then convert into fisheye in post, but since you need fisheye straight from renderer... chrome ball is the only option at the moment, i'm affraid. Unless you want to model fhisheye lens glasses and render through them :]

[maru]

Unless you want to model fhisheye lens glasses and render through them :]

That may not be as hard or insane as it sounds. Unless you need to perfectly recreate some real lens.

Although I am not sure if the elements would appear correctly if the only thing rendered would be reflection (chrome ball) or refraction (lens). Probably not.

[Prettysimple]

Unless you want to model fhisheye lens glasses and render through them :]

That may not be as hard or insane as it sounds. Unless you need to perfectly recreate some real lens.

Although I am not sure if the elements would appear correctly if the only thing rendered would be reflection (chrome ball) or refraction (lens). Probably not.

I was actually making some test renders with the lens method since I didn't exactly get how to do the first one.
I made half a sphere with only refraction and a little thickness to it and put it on front of the camera, I tried unchecking "visible in masks" in the lenses material but this way even though we can see the passes correctly the distortion goes away :D

So I thought I could work this way while creating the scenes and once I'm done I could hide the lens, render everything straight and then try to match these to my "raw" distorded render. There is obviously no 1 to 1 accuracy but luckily it's not required for what I do. The only thing left is to figure out how to do proper fisheye in Photoshop or else.

[romullus]

So what's stopping you from doing this?:

[Prettysimple]

So what's stopping you from doing this?:

Only because I didn't understand yet how to apply this technique to my process. :)

I have to match my render to a 2D sketch that is 3040x1920 and my final output has to be the same size.

Edit : Without the black borders