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Hi Al
This works really well - will the HDRi lighting channel option be available in standard packet mode in the future ?
Thanks
Boothy
The lighting channel for a full panoramic HDRi (such as the preset), is the sky channel.
The packet/path-tracer channel question only applied to Planar HDri backgrounds. So you should just avoid them.
As a "next step" Rich hopes to write something to take a flat image, and turn it into a full HDRI - by applying it to the proper place in the HDRi based on the current view and providing a simple mirror of the image on the other side of he sphere. This will work for a lot of things.
Give me some hints about what you mean by "Tweak Tonally"
One thing we might be able to do is to use the full-panoramic HDRi for reflection and illumination - but not visible, and then extract a rectilinear piece from it as an "image background" which you could then apply filters to.
In you example, that would let you "tweak" just the visile sky in the windows - but use lighting channels for the illumination and reflection.
Hi Al
I am sure we have had this conversation a few times over - but I will give it another go. Please see sample image below - I have produced this in Photoshop to illustrate what I mean by `tweaking tonally`.
Being able to position the backround image prior to render is a big leap forward,however, its just has important to blend background image exposure, colour temp (NXT tends to render very much to the cool end of spectrum and therefore needs adjusting to simulate interior lights or blend with `warm`background), contrast noise etc to the resultant render - this is very difficult to do post \outset of render due to the changing nature of image during process and passes. I am sure it would be very difficult to adjust these elements\filters of background image post render - but it would be really useful to at least tweak the brightness \exposure post render to try and blend background with finished render - similar to tweaking self glow in lighting channels. Now here comes the hard part - I produce a lot of interior views and therefore a lot of my background images are seen through windows. The concept of tonally adjusting a set background image which retains elements such has reflections would be the ideal option (has opposed to material channels which only adjusts a `flat`layer.
In the image below - the first shot is blending into scene quite well , the second image is far to exposed - this occurs often with background images.
This can be achieved in a roundabout way by attaching a background image has a texture to a face behind model and applying a self glow to adjust light levels but you then have all the issues with casting \recieving shadows, over exposure by SU sun etc.
Does that make sense ?
Boothy
Edit: What I tend to do now is produce 2 files from nxtimage file with varying levels of sun\sky exposure to make window reflections more pronounced and then overlay on top of one another in PS to provide some adjustment. This is still a big leap forward from earlier times when I had to contruct background\reflections from scratch.
This can be achieved in a roundabout way by attaching a background image has a texture to a face behind model and applying a self glow to adjust light levels but you then have all the issues with casting \recieving shadows, over exposure by SU sun etc.
This is what I meant by having an easy way to grab an actual background image from the HDRi. The HDRi and Sky channel would still be used to adjust illumination and reflection. But the background image could be tweaked post-process to change the actual visibility.
We'll be interested to try it some time...
You can make an image now - which is just the HDRi in your current view by hiding all the geometry, and rendering. Then save the rendered image, use it as a visible background, and leave the HDRi sky on for just illumination and reflection.
Then re-render - you can use the Sky lighting channel to adjust the HDRi illumination and reflection, and use Rich's background wizard to adjust the contrast and brightness of the background image. Rich is thinking of a button to do this for you in one step.
Hi Al
When I tried test the HDRi reflections changed when adjusting `sky` channel but not the background image which is the element I want to adjust. I did try saving `background`in initial render as HDRi but could not get the background to render as HDRi with HDRi reflections present so therefore used jpeg version has background.
Boothy
It works !
Well done Al - that works a treat - My problem was that either the `make background visible`button is reversed (I had to untick it to make it work) or there are so many ways now to switch layers on and off that I am totally confused.
I must admit I was totally unaware that the sky channel affected the HDRi planar channel in standard mode - you learn something everyday !
I will look forward to `Rich`s Button` but its no hardship to run a quick single pass render to achieve reflections anyway. The key result is the affect of sky channel on HDRi - I was toatally oblivious to that one.
I know I am an old saddo - but you have made my day with that solution
Thanks Again
Boothy
Hi Again
I am still doing something wrong - when I unticked background I was just switching to HDRi sky and adjusting that - in lighting channels. Cannot get a `NXT generated` planar HDRi to show in layer wizard or render - although the preview is generated in background tab. Will try later if time - day job calling - definately needs `button` to if not simplify, make sure all the right switches are set.
Boothy
Edit:Presssing show all in wizard seems to work in render - need to test over larger pass run
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