Basic compositing using both 2D and 3D

Place and lock the camera

First let’s place the camera, so we can see the same thing, here is how I did place mine:
Note that I’ve also locked my camera just to be sure.

Add a 2D layer

In Smode you can composite with 2D and 3D layers.
So now go into the Standard Pack > Texture > EnvMaps and drag and drop the Sky.jpg image before the mountain (as showed on the image) and move it a little bit up.
To see the differences between the composited images and the 3D Layers, you can split the screen by pressing the icon circled in blue.
By default the 3D viewport camera is the current composition camera. So in the viewport to the left, select Vizualiser Camera to navigate in the 3D viewport without breaking your composition.
If you are tired of all the helpers in the viewport or you want to see blue outlines when you select a 3D Layer, you can turn off / activate them by clicking on the area circled in green on this image.

Add a light

Now let’s be “foufou” and create a Directional Light Orthographic light casting shadows Read More (Light>Directional light). You can move and see it in the 3D viewport.
Be sure to set up your light according to the size of your scene. To be easier, here is a screenshot to show how I placed it in this example. Note that in this case, the size in it's parameters will have no effect on the light intensity but only on it's helper size.
I put the shadow bias at 10 because of the size of the scene.
Don't forget to check the Advanced parameters mode to fully see what lights have to offer.

Create Depth using the Z-Buffer

Put the 3D plane inside od a composition ( Ctrl+shift+C ) and rename it 3D mountain
Create a new uniform layer ( Right click > 2D layer > Uniform ) and turn it to white.
Put a Depth mask Select each pixel depending on a associated depth-value Read More over this layer ( Right click > Masks > Depth Mask )
Now we are going to use the uniform layer to generate the fog through the layer mask.
For that let's use the depth map of the composition that contains the 3D mountain by selecting it in the " Depth mask Select each pixel depending on a associated depth-value Read More " value of the depth mask parameters.
Set up the uniform / depth mask like showed below :
Note that you can create any effect you want based on Depth simply by using a depth mask over them.
Let's add some dark on the foreground, for that do the same operation as before but this time leave the uniform black, and then put a Depth mask Select each pixel depending on a associated depth-value Read More over it and set it up like that :

Let's add 2D post effects

Now here is the fun part, we are going to add a lot of post effects over the current image to make it prettier.
In this example I've added 3 modifier's presets :
Right Click > Modifiers > Color > Colorize Re-colorize an image by applying a color gradient Read More > Warm filter 2
Right Click > Modifiers > Color > Exposure Control the contrast of an image by adjusting its tonality Read More > Master
Right Click > Modifiers > Color > Stylize > Chromatic Aberration Lens chromatic aberration effect Read More
Let's add also a little vignetting :
- Create a black uniform ( right click > 2D layers > Uniform )
- Ass a Circle mask preset named Large vignet just as showed below ( Right click > Masks > Circle Mask )
with this settings:
For the remainder of this tutorial, I rename this uniform "Vignet"

Lens Flare

First, create a Lens Flare A bright light (optical aberration effect) Read More with the Horizontal Light preset ( 2D Layers>Lens Flare>>Horizontal Light ), then set it up like showed below.
You can set it up either in it's parameters or in the viewport in "edit mode", to activate this mode, click on the button circled in green on the screenshot.