combining custom environment texture with sun

[crackfox]

hi,

not sure how to get this right.

i am trying to use an hdr or exr as a skybox but need to complement it with a sun, obviously.
it seems as if the sun system is tied to the octane sky and i cant make any sense of it. steps:

- i create a planetary env.
- i added the exr as a visibile environment. the problem however is that the texture produces no light whatsoever. it acts as a plate.
- if i choose a simple texture environment i dont get the sun and cant make it (like in every other software) independently of the environment map.


just lost hours trying to get around this and it exemplifies the frustration i have with octane in blender, to be honest.

as a side question -how are the two values in the environment tab power and sky related? if power is 0 sun has no effect no matter what value. do they multiply with each other?
also gamma setting was a pain to setup since there are so many options for tweaking gama (in texture node, in the rendering settings colour management and in the camera imager)
how do i best get about this - the time i did manage it the gamma was alright seen through the camera but the free look viewport was wrong again...

[crackfox]

let me add to this some screenshots. i dont think this works as intended.

4 screenshots:

1 - i did a regular texture environment. hdr´s with brighter sun do cast harder shadows but is impossible to control.
there are two "power" values seemingly doing the same think. confusing as hell but thats beside the point.
the scene does not look bad but i need to dim the light a bit.

2 - i lower the light to a fraction. the ambient light is indeed very low but the direct light is still at its full intensity

3 - i try to lower the other power (textur env) parameter to 0, basically fiddling around to see what is working. the scene as expected goes black.

4. i bring back the same parameter, and now the lighting looks much more as something i expected in the first place, since the power level is set to 1/100.(very imperceptible ambient and direct light)

5. i reset the first value i´ve changed back to 1, and just try the same trick: setting the power of texure env node to 0 and then 1, and the result looks as if there is no direct light at all, only ambient.

the fact that changing and resetting of texture env power level can produce two completely opposite results, instead of reverting to its original look, tells me there is something very wrong here. this cant be right


i am trying to keep this short and spare you my permanent frustration with octane, especially in blender host.

here is the packed blend file fwiw. https://we.tl/t-zOKGEEFLcY

[grimm]

I think you have a couple of things you might want to change. First, I would start with the Daylight Environment node and then plugin your .exr into the Sky texture pin. This is how I usually mix the two together. Also your .exr is very strong, it looks better with a gamma of 1 instead of 2.2. I usually play with it because some HDR images have the gamma baked in. I also put textures on the objects in the scene, I know that Octane will default to just plain diffuse but I like to be sure. Hope this helps some,

[crackfox]

i appreciate your tips grimm, thanks.

that method does let me use both sun and the custom sky map.
problems remain, and its all due to gamma i think. the buggy behaviour i mentioned i believe is a different problem too. going back and forth between parameters should not be causing completely different unpredictable results.

if i understood correctly, you are saying that each hdr has a different gamma value baked in, similar to displacement map that work best with certain specific value.
i was under the impression that its either 1 or 2.2 and felt dirty when i was winging it with some random values.

after i initially posted, i managed to get some more acceptable results by putting a colour corr node after the sky texture. it seemed to clamp the overexposed parts. but back to your example:

ive set the gamma of the texture to 1.8, seems to be a nice enough balance of contrast and intensity.(1 ist too washed out. i still want to have more dramatic darker clouds)
however, there is still a huge difference between the sky and the actual sun.
i would expect to modify the sky map and sun independently but power actually changes both.

it seems the sun is too bright in the texturemap for some reason, so maybe the values in the hdr are off too. octane has no curve correction, i will try and trim it down in photoshop.

cheers,

[crackfox]

just to add, with a volume medium makes the whole thing even worse - the fog is overexposed.

i suppose what need is to reduce the intensity of the sun spot in texture but retain the light in the atmosphere.
in 3ds max there was an importer that could calibrate this but cant find a way here...

i tried the same thing in cycles:

-imported the texture
-created the sun
-lined them up

finished. took me under two minutes, attached.

[grimm]

I suspect that most of your issues are with the HDRI file just not being very good quality. I have had similar issues with poor HDR files before and Octane doesn't give you much leeway to handle them for some reason. Another thing I noticed with your file is that you still have the Blender color management turned on. Turning that off can help a lot with these issues. I brought in one of my good HDRI files here and tried it out. It was much easier to handle than the one in your file.

Fog has issues so YMMV on that depending on how you set it up.

[crackfox]

thanks again grimm,

the hdr is just a quick test environment. i can up the resolution and sampling and make it better but i honestly dont think its the culprit. i saved it out as a 32bit image fwiw too.
like i wrote earlier - with cycles i managed to get the look i wanted with ease. attached is a screenshot. the funny thing is, i have been using octane far longer than cycles.

i notice only my own thread got no official reply so i guess i will take that as a hint and bow out from this subforum. i keep trying to make octane work for me in blender but there are issues like this make me lose hours and end up in frustration, so maybe my tone is not the best.

i am interested what fog issues you are referring to. i have had my set of problems with it aswell. finding the sweetspot i needed was not possible since the finetuning.
some values did acted counter intuitively and changing some values by a tiny increment had huge jumps in results (i did a thread on this). i never saw any acknowledgment from otoy though.

----------

a quick post scriptum, i just tried to import the same image into unreal engine octane and it works perfectly. i dropped the texture into the env slot and had a distant light act as sun.
no issues whatsoever. i can even modify the sun and enviroment light independently and setting it up took 30 seconds:

- the distant light intensity modifies the env map strenght
- the sun intensity modifies the direct light strenght

btw - unreal engine plugin, even in its early stage, has the native material and light support. i can even get a spotlight going if i want to.
creating and finetuning fog is a breeze too, nothing like the issues in blender.
i dont want to come off insulting but blender plugin is nowhere near usable. maybe its the underlying blender code that is causing troubles, but again e-cycles works like a charm.

thanks for your thoughts. i think, for the 20th time i will default to e-cycles.

[linograndiotoy]

octane has no curve correction, i will try and trim it down in photoshop.

cheers,

You can use the Use Curves option in Color Management.
Are your Color Correction options set as needed, by the way?

* Display Device: sRGB
* View Transform: RAW
* Look: None
* Exposure: 0.0
* Gamma: 1.0

[linograndiotoy]

I just checked your file.
As i suspected, your color correction settings are incorrect (the color correction was basically applied twice).
You should use Octane's color correction option, which translates in settings View Transform to Raw.
Normally the gamma for HDRI should be set to 1, but of course it's possible to tweak the value a little bit to get the wanted lighting.
I hope this helps.

[linograndiotoy]

i dont want to come off insulting but blender plugin is nowhere near usable.

We have so many users currently using it in any kind of production (some of those really high-end) that quite evidently disagree with your statement.
The Octane integration in Blender is currently one of the best available for any 3D software, probably only beaten by the one for Cinema.