What should I do to render this in Cycles?

I have been learning Blender 3D since 2008. A few years ago I made models of a forest on Blender 2.73a. The image I’m posting here is rendered using the Blender Render Engine because I’ don’t know how to use Cycles.
I would like to ask you (especially older Blender 3D users) what should I do to render this image using Cycles? Is it enough to change the textures of all objects? What about the light? Does it take a very long time to render so many objects using the Cycles engine?
Is it difficult to learn how to create realistic images using Cycles?


I am not an old Blender user (started since 2021), but it seems to me, like this question could be a rhetorical one. That is to say: to make a scene like this one (or similar to this) you need to do a deep work with the lighting, textures, fog, particles etc.

I mean that there (imo) can’t really be a one simple asnwer on that question.

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Open file in 2.79 (latest version with blender internal support) and try using material utils addon internal to cycles conversion tool:

But I imagine it’s still gonna require a lot of manual fixing.

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Hey ! a fellow blender artist from the past ? !

In general Cycles is slower than BI, unless you used BI functionality like raytracing for shadows , reflections, AO … All these are heavy on BI but generally faster in Cycles… But on the overall Cycles is the slow but top quality engine, and you can use Eevee engine that is faster but less precise.

On the overall Cycles makes things much simpler. But the logic is different so it might take a bit of time to adapt.

That’s generally fine a lot of geometry isn’t really a problem ! The main thing with Cycles is light bounces, and just like with photo a dark image with low lighting produces noise.
The whole battle with cycles is to get rid of the noise, that’s why there is a denoiser . Which works fine for static image, but a bit less in animation.

On that particular image, I think it’s better to redo the lighting. You can keep the main sources and bring back each lights. I suspect that many light sources won’t be needed and might get in the way.
There isn’t stuff like Halo spot lights ( to do god rays) you’ll have to do something else for that.

For someone experienced with Cycles, it shouldn’t be too complicated to make a good image out of your scene. But to learn cycles it will probably be a bit overwhelming.

Try to learn the engine one feature at a time, ( material, light, optimisations …) with very simple scene and eventually move on to your scene.

When I switched at first it was a bit difficult, but in the end for realistic rendering I really don’t want to go back to BI, cycles is much easy to work with, but you’ll have to un-learn all the little cheats that was needed with old school render engines !

Good luck !


Isolate some of your assets and start little by little - with the tree’s for example.
Get a good HDRI for illumination and render them out using your old textures with cycles.
See how that looks. Then adjust your textures/shaders.
Essentially, you have to learn the 2 main things that make up the visual world - the materials of objects and the light bouncing around.
Lights are trivial - you should know how these work, learning the shader nodes of cycles might take some time, but you’ll be fine with the principled shader for 99% of the time.
You want to learn the Physic based shading system that the whole 3D industry is using since ~10 years, its the foundation of almost all modern renderers.
This should be your starting point, once you’ve got that down, the rest will fall into place.

Amount of objects isn’t so much the issue, the complexity of materials and light interaction makes a scene slow or fast.
A concrete jungle will render faster than a natural jungle with tons of translucent foliage and more complex natural shapes.

Yes, kinda, but by using a pathtracer a ton of effects that make an image realistic become easy and effortless.
80/20 rule applies here. Its easy with cycles to get the first 80% right, you’ll have to work harder for the last %.

Thank you all for these tips!
It’s a pity that I will have to study the new Blender interface (the one with the Eevee engine - because I care about rendering speed) I have mastered the old interface (v.2.5 - v.2.9) very well.
If someone would have time to help me “start” this forest scene, I would be very grateful (I mean an example .blend file with a forest scene - maybe someone has already done it or knows a link?). I would like to see what are the scene settings, light parameters, textures for trees, leaves, wet stones, lake water, etc. What does a “correct” .blend file with a forest look like in Cycles?