Elements - Compositing - Phtoshop Layers

[bernhard]

Hello,

I've already read some interesting threads about comping the elements.
But I can't follow completly some of the descriptions.

I would like to composite some of the major elements with Photoshop.

Is there any quick snapshot how the layers should be structered, in order to can change the following settings:

- Reflections
- Refractions
- Direct Light
- GI
- Shadows


I was going through the node based thread from nichols - and it all starts with the Diffuse... is the Diffuse he described the VrayDffisueFilter ?

Also his version is node based - I would like to use the major elements like above in Photoshop, but with Multiply it doesn't really work....

I really would like to nail down that part...

thx for every little help,
bernhard

[rivoli]

you basically have to group elements, blend, and then blend again. something like: group diffuse and gi, multiply them. group dif and lighting, multiply them. add one group to the other. then just add reflections, speculars and so on..

here's something quickly put together. it's not exactly correct, I blame it on the non linear workflow I used and the ldr tgas. I guess. I never use ps to do this kind of things.

on the left the comped elements, and on the right the rgb output out of vray.

[m_hinks]

Yeah Id do the same as this, but make the Diffuse pass a smart object, then you can control the materials source colour in the smart object, and it will update both lighting elements.

I have found that with an 8-bit file, the layers do not quite add together exactly, but if you can live with it, its a good workflow.

[rivoli]

Yeah Id do the same as this, but make the Diffuse pass a smart object, then you can control the materials source colour in the smart object, and it will update both lighting elements.

smart never thought of it.

[bernhard]

hmm....

Thank you rivoli and m_hinks, I really appreciate your help.


well, this is what I did so far:

original render from Scene:


comping so far:


and here is my layer structure:



as you can see, the composition is slightly different to the origianl render.. the composition is brighter.

so the question is: what do I miss in my actual composition, in order to reach the original render ?


I also want to keep in mind, that I used Pass Through on the gropus, and all the other layers are on Linear Dodge.


I really would like to nail down the layer structure, so I've uploaded all the files:

DOWNLOAD MAX 9 file:
http://www.bernhardrieder.com/ask/test_comping_001.max

DOWNLOAD PSD file:
http://www.bernhardrieder.com/ask/setup_001.psd



Additional questions:

a) VrayShadow
If I render that element, it's just black... shouldn't there be the shadows from the VrayLight ? And how to add to the composition ? Again with Linear Ddoge ?

b) SmartObject:
If I convert my Diffuse Layer into a Smart Object I can't change anymore the Levels, or Brightness or anything else like Hue, Saturation.... hmm... I guess I do something wrong...

c) Specular:
Why the Specular pass if we already have the Reflection pass ?
I guess thre is a difference, but what's ecatly the difference ?


d) Raw Raw and Raw...
So what is that all about ? Why do we have RawGI as instance, if we already have ... let say VrayGI, or VrayLighting ?
RawGI x Diffuse = VrayGI ........ ??????


okay, so far so good... I didn't make much comping work, but now it's time to get the full power of vray....


thank you so much for every little help,
bernhard

[m_hinks]

The exter VrayLighting element after the two groups is not needed, but you do need the specular ele to sit on the top of the stack. I should look correct then.

The smart object, you make it, and use it in the two locations, then double click it to edit it, and add effect, material masks etc.

I have no time today to look at the files, but I wil try!!

[rivoli]

as you can see, the composition is slightly different to the origianl render.. the composition is brighter.

so the question is: what do I miss in my actual composition, in order to reach the original render ?

in this case you forgot to assign a vray mat to the ground plane. some elements doesn't work with non vray mat, in fact both rawlighting and rawgi didn't take it into account and rendered it black.

then you don't need the vray lighting element, it's just redundant. either you use the raw element multiplied by the diffuse or you use the lighting element, which basically is diffuse and raw already multiplied (same goes for gi instead of rawgi).

a) VrayShadow
If I render that element, it's just black... shouldn't there be the shadows from the VrayLight ? And how to add to the composition ? Again with Linear Ddoge ?

it renders black because the ground plane miss a vray mat, same as above. if you had a vray mat assigned, it would basically give you a matte of the shadows that you could use for colour correction, tweaking and so on..

c) Specular:
Why the Specular pass if we already have the Reflection pass ?
I guess thre is a difference, but what's ecatly the difference ?

you are right in saying that speculars are reflections, but vray treat them separately (you can even turn them on or off on a per light basis), so it makes sense to have a distinct element.

RawGI x Diffuse = VrayGI ........ ??????

the raw versions are there to give you more control over the single elements (diffuse and lighting and gi), I guess.

[bernhard]

doesn't match...

Okay, thx again for your reply, I really appreciate that.

I followed your idea, which makes really sense, but unfortunately, the theory didnt' work.

@VrayLight:

When I follow your explanations you meant that
a) RawGI x Diffuse + RawLight x Diffuse = VrayLight

so I was running a test - to break down the VrayLight, see below:




as you can see, it doesn't look like that the breakdown works, because it's not matching the original VrayLight element.....

I want to focus on the VrayLight Element, because if I can work it out, it shouldn't be as hard to add the Reflections and Refractions elements.

so....... and now ? What you think is missing in the VrayLight Composition ?

bernhard


ps: I've changed all to VrayMat's in the max scene file, you can download the updated max9 scene file here: http://www.bernhardrieder.com/ask/test_comping_001.max

[rivoli]

@VrayLight:

When I follow your explanations you meant that
a) RawGI x Diffuse + RawLight x Diffuse = VrayLight

um, not exactly. I meant using the lighting element it's like using rawlighting multiplied by diffuse, but with less control over the single elements.
(the same goes for reflection and refraction, instead of being limited by them you can use rawrefraction * refraction filter and rawreflection * reflection filter).
in your test you should leave out the gi elements, and get the lighting one only multiplying rawlighting and difuse.

[dlparisi]

For your earlier test with the reflective materials...

Everything comps together just fine as long as you stay in 32bit mode within photoshop (the "pass-throughs" should be set to linear dodge though.) Once you switch it to 8bit it gets screwed up because I think it starts clamping things when it shouldn't. Other than some edge artifacts it's perfect (can't explain the problems with the edges though). Get my photoshop file here in case it doesn't work for you...

[bernhard]

hmm..

hmm, thx again for your reply...

@rivoli:
I need to check that but what I could see so far, if I use
RawLight x Diffuse ...... it is NOT equal VrayLight

here is the test:


I assume we still miss one render element in order to match the VrayLight - I guess it's not just RawLight x Diffuse... hmm....

dlparisi mentioned, that it will not work in 8bit... well, all my render elements were saved out as .tif 8 bit files....

but here comes the next challenge:
when I render 32bit, and I open in Photoshop, I can't create some new layers... well, yeahm does mkae sense... 32bit another challenge... but I really would like to nail down the VrayLight Element first...

that means: Which render elements are building the VrayLight Element ?


@dlparisi:
not sure if you wanted to upload a .psd file that shows all different render elements on different layers... but the psd fiel I've downloaded from you has just one layer - with the final image....


hmmm... thank you for your support, suggestions and help,
that's awesome...

bernhard

[dlparisi]

Just checked... the file has all of the layers in it. Are you in CS3? I think there were some improvements to 32bit mode that allows for more, but still not all, operations to work in 32 bit. It may also be a problem with the color setings in photoshop (linear vs. sRGB vs. etc) but I'm not sure.

Taking a look at your images above it, looks the same for me in 8-bit mode. 32bit is fine. The problem is that you have areas in (at least) the raw lighting element that are clamped to 255 in an 8 bit tif so there's no way it's going to match. There's no way I know of to compensate for this other than to just use the VrayLighting element instead or save to EXR.

[bernhard]

hmm..

Hello again,

thx for your fast reply...

I know, I double checked it, vlado published it as well, that the
RawLight x Diffsue = VrayLight

but here, this is the result from my 8 bit renders, I made an animated gif so you can better compare:




@psd:
ohh, that explains, I still have CS2...
so, when the VrayLight is finished, I will focus on the 32bit, that's very intersting...


hmm.. well, and what do you think now ?
why does the RawLight x Diffuse look different ?

It's not a big difference, yep.. but you can clearly see, that the colors are not as saturated, and the light on the goundplane especially in the area behind the sphere is brighter.... and in generell you do have more contrast...


bernhard

[dlparisi]

The problem is that you're using the 8-bit tif elements to do the composite and you have portions of the VrayRawLighting that are clamped to 255 for at least one of the RGB channels. For example, if we normalize the RGB "255" values to "1", in the 8-bit tif they are represented as 1. In the EXR they go above 1, let's say 1.5. These values are then multiplied by the diffuse color value, let's say it's .7. So in the 8 bit tif, 1*.7=.7, but in the 32 bit EXR it's 1.5*.7=10.5. SUffice it to say that'll never match. The problem is really only present on the "multiply" layers in this case, the Linear dodge (add) layers should be just fine which is why the the composite works out just fine as an 8-bit composite as long as you don't use the "RAW" elements. Hope this all makes sense.

[bernhard]

hmm...

Hello hello,

well, yes, that makes totally sense dlparisi. Thank you for this great explaination.
I guess now it's time for the 32bit format.

My main goal would be to use the 32bit version, because I have more control.
I usually use After Effects and again I was a bit surprised when I used the same composition that worked with 8bit - just reloaded with the 32bit images and kabumm... look at the result:



as you can see on the left side is the 32bit version, and for some reason the same composition that worked with 8bit didn't work with 32bit.

Or is it again just After Effects which can't handle 32bit ? The test was done with AE CS3 pro.

I am not sure if just AE CS3 is causing that issue, so I've uploaded my 32bit elements, compressed as a .zip, you can download here:
http://www.bernhardrieder.com/ask/elements_32bit.zip


hmmm..., still a riddle .....

bernhard