Giving up on octane

[mojave]

Sure, your kernel settings can make a big difference when rendering this kind of effects, for instance the diffuse depth specifies how many bounces are allowed per ray, so surfaces hidden from the main light source should get more diffuse lighting contribution.

https://docs.otoy.com/#60Kernels

Also, you may want to increase the intensity of your light source and decrease the exposure in the imager settings to compensate so you get a noise free image faster.

Hope that helps getting your result right.

[AndyM1969]

Nope, still doesn't work and I have ramped it to max. the problem is this, if i take away the scattering medium I get perfect lighting all around, as soon as I plug in the medium node the whole scene goes dark.

[ristoraven]

As in your reference picture, we can see that tree on the left is also basically just a silhuette. If walk in a real world forest, the whole atmosphere adds light and comes from all around = you should use a HDRI image. Then in your reference photo, the "light source" covers the whole background and it is not just a spotlight. Also the mist in the reference photo scatters the light all around. This is not easy. If you try to produce similar effect with a real camera, in a real studio, where spotlight aims directly at your camera, behind objects, chances of getting "just silhuettes" are about 99%.

[ristoraven]

With octane, pretty much everything I have learned from real life photography, does apply. Welcome to unbiased rendering

[FrankPooleFloating]

Andy, how are your trees textured?.. Do you have bump maps, or better yet, displacement?.. If you are using a Diffuse material, this may be part of the problem... A Glossy with high Roughness and just a wee bit of Specular (preferably maps for both) might go a long way to helping bring out some details in the bark facing us. Almost all real world objects have some spec...

Everyone is trying to help you big guy. No one wants to see anyone get so frustrated they end up saying "eff this" and walk away from Octane completely. Most of the guys here are among the most helpful I have ever seen... anywhere.

[ristoraven]

Here's my quick test with Juanjos scene. I dropped the density to 0.02. Tree leaves and grass have slight transmission setup, so that the light passes trough. On the ground I used displacement map to generate details, instanced some grass to it, from where the light can bounce like crazy and illuminate all the details.. Background is LDR image (as opposed to HDR), but it gives a nice tone to the scene.. I dropped the light power to just 5000. Imager node is set to "linear"..

These things needs a lot of fiddling. Give LW/Octane another three months. This is very different to what it is with LW native renderer. It is absolutely essential to think how the light / cameras works in the real world. Same tricks what professional photgraphers use, do apply. For example adding a reflective surface/additional light source behind a camera to shed more light to the foreground - is not cheating. It's pro.

Edit.

..and of course I used a PMC kernel! Also postProcess node, added some bloom effect..

[ristoraven]

BTW, you are not going to like this: you can't sell your license.

It is illegal, under the New Zealand laws, and you have agreed to these terms when you purchased the licenses.

[Notiusweb]

@AndyM1969

Let me ask - have you tried as Ristoraven suggested having a subtle light source behind you as the viewer, pointing towards the silhouetted side of the trees, maybe you could fake the look you want?
Anyone looking at the image will likely not worry how you made it, they will only care how it looks
Also, how does the native LW rendered image come out, if you could show a subtle difference you might help the developer come across a bug or inefficiency of Octane, if there was one.
Try to find as much detail as you can.

Anyway, don't give up!

[Terryvfx]

Dropped Octane because he couldn't get a misty forest what a damn joke! like many already said consider doing all of those things in post or with the native render.

[AndyM1969]

Thanks for the support TerryVFX,