Overrides Completely Unaffected

[dj_buckley]

Is there anyway to have the environment overrides completely unaffected by anything in the frame buffer?  The Tonemap Control just doesn't seem to cut it at all.  And yes I've tried restarting the renders etc etc.

I need to render with the backplate visible (full 360 pano) and I'm also using it for reflections.

The issue is regardless of the tonemap control settings, something on the backplate is affected, even after a restart.

The only way I can get full 1:1 representation of the backplate I see in Photoshop, inside of Corona, is by not touching anything at all in the frame buffer.

I'm aware of LUT issues regardless of tonemap control settings, soI'm avoiding those.  Filmic Highlights/Shadows affects the backplate horribly (saturated pixels everywhere - unless they're both set at 0 or both set at 1).  Adjusting curves affects the backplate, even after restarting the render etc etc.

Is it possible, or is the only solution to render twice and comp back in?  Although this isn't a solution for reflections

[TomG]

Not everything in the Tone Mapping can be "reversed" to be undone - in fact, more things can't be reversed than can be (and this has always been the case - the Max UI has tooltip popups to say if something can't be undone, warning about it being nonlinear output). The general guide is to keep it at very simple adjustments such as Exposure and White Balance if you need to have the background unaffected, and perform tone mapping in post (with masks).

[dj_buckley]

Thanks for the quick response Tom.

Hmm okay - I thought a curve would have been able to be reversed by just applying the inverse curve.  My knowledge is non-existent though on the technical possibilities.

Here's my thinking anyway and why I was attempting it.

The backplate is shot with a camera and the output is non-linear i.e. already has the camera response saved into it etc.

The render however is linear and PBR based, kept within stricter sRGB ranges, so I'm trying to match the scene lighting with that in the visible backplate and at the same time match the tonemapping of the render to the backplate (or at least as close as possible).  Once I've got that bit, then I can get freaky with exposure if I want to.  i.e. once both backplate and render are at the same starting point.  So adjust the 3d interior exposure and the backplate scales with it appropriately as it would in reality etc etc.

The problem with post and masks is that it doesn't help rendered reflections.

Standard procedure for us tends to be capturing a full 360 on site for each project, to use as reflections/refractions etc, and then we have full freedom with 3d cameras and everything matches up with backplates whether comped or rendered.  If sticking to a strict PBR workflow inside of the 3d program, it appears this isn't really possible without some reverse hack somewhere along the line.