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Cornucopia3D "Making of"

     

Each week, Cornucopia3D is turning the spotlight on a member of the Vue community. There are so many interesting people doing wonderful things with the Vue line of products, we wanted to share the wealth!

This week, Drea Horvath is sharing her Subsurface Scattering secrets with us.

 

 

Making of "Spring Slime" by Drea Horvath

The inspiration to create this scene was no other than the nice, creative and funny renders made by my fellow Vue artists, as this little snail model got so popular. First of all, many thanks to Martin Lubic for the model, and to Barry Marshall for turning the model into a nice rigged Vue model.  

Instead of getting into the depth of all elements in the scene, in this tutorial, I will focus on the key element the whole scene relies on: subsurface scattering (SSS). SSS is responsible for the light on the foreground plants’ petals, leaves and stem, for the look of the snails, for every translucent material – for the realism of this image. As I’ve noticed, SSS is barely mentioned in tutorials, and for me it looks like one of the “less popular” features of Vue, although it is an important factor in such close-up scenes where the focus is on a beautiful plant, or a snail – or both! 


 

Reference

As I was getting my hands on this snail, I found a nice article that was featuring macro shots of snails. Those photos were perfect references for this project; they helped me a lot in getting the same look, color, and SSS on the skin. The article can be found here; it’s worth to check: http://news.distractify.com/culture/arts/macro-photos-of-snails/?v=1

Tweaking the Snail

Before running into this topic, the snail is shared in our Vue Galleries group on Facebook; feel free to download it.

Let’s start with the skin. Based on the reference photos, the first thing I did was to make the skin color a bit lighter. I left the highlight settings as they were – bright and shiny (84% brightness and 87% intensity). In Translucency SSS settings, I increased the depth a bit to 6.38cm, and set a balance of 12%, so the light under the skin surface scatters into more random directions.

I left all other settings as they were: Refraction index at 1, Quality boost at None (note: normally I reduce the quality to -1 to -2, depending on the material, but in this case, None was the minimum value that didn’t produce artifacts on the snail’s skin), I set the Anisotropy to -0.68 (backward) and left Multiple scattering enabled.

Since there is a slight, but noticeable translucency on the shells as well on several reference photos, I enabled SSS on the shell. You can see my settings on the screenshot below:


For my preference, I also made the color of the shell lighter.

Foreground Plants

The main plant in focus in this scene is a nicely detailed static plant from xFrog's Flowers collection but any plant could be chosen. These plants come with SSS enabled, and you can tweak them based on your scene and preference. Since the leaves don’t play much role in this scene, I left them as they were. Let’s see the flower’s Translucency settings, since that is the element that steals the show here.

 

The 10m depth and the slight balance towards absorption (or single scattering) created a vivid, bright effect with a nice – but not too much – contrast between the areas of direct lighting (edge of the flower) and the areas of indirect lighting in the middle. An effect quality of -2 didn’t cause any artifacts or any virtual quality loss, but it made the rendering process faster. In most cases, -2 works perfectly with thin plant surfaces, such as petals and leaves.

Since this plant is one of the key objects of the scene and it’s very close to the camera, I needed to enable Translucency on the stem as well to match the rest of the plant, and for a realistic effect, of course. Especially because the Sun light comes from behind the plant.

 

For the rest of the foreground plants (and to the mid-ground) I picked water lilies. They also came with SSS enabled on the leaves and flowers, and they didn’t need any tweak. The only thing I changed on the leaves was the highlight. Since these leaves are supposed to be wet, I increased the intensity to 76% and the Global size to 63%. Plus, I changed the highlight color to a light, but warm color. With these settings I achieved a bright, warm highlight, like the reflection of light on a wet leaf in the morning.

 

Subsurface scattering is definitely a nice feature, but it is also a tricky thing to play with. These settings worked perfectly in this particular scene, but the effects can be pretty scene-dependent. Just take time to experiment, play with the sliders, see how the translucent characteristics of an object/material work in practice with different settings.

Lighting & Atmosphere

The SSS effect give a more spectacular picture if the translucent objects are lit from the opposite side of the camera view, so I placed the Sun behind the objects, on a lower angle. My goal was to achieve that the light scatters evenly on the edge of the petals. After some experiments, I found the following Sun position the best:

For a brighter Sun and a more dramatic effect, I drastically increased the size and the corona of the Sun.

In this scene I used the new Photometric lighting model, but I ticked “Allow overriding photometric settings”, so I could adjust the Global lighting. I didn’t want too dark shadows, so I drastically increased the Gain to 10. Below are my atmospheric settings:

 
 

Camera settings

For such a small-scale scene, it was not a question that I would set up the Depth of Field effect in Vue, and render the scene using Fast Hybrid 2.5D blur rendering method. For this, I set the target of focus. Since I wanted the camera to focus on the snail, the flower and the other snail (in other words, I wanted them to look as sharp as possible), I grouped these 3 objects, and set the group (“Group 4”) as the target.


The rest of the camera settings are below. I used a 50mm focal length, and in such a small-scale scene, 1% blur was enough to get the Depth of Field effect I wanted.

 

Rendering

As I’ve mentioned before, I rendered the scene using Vue’s Fast Hybrid 2.5D blur rendering method. This is a systematic anti-aliasing rendering strategy that is linked to the camera’s Depth of Field settings (blur, focus, target). The more passes (subrays ber pixel) you render, the better quality image (less ray-tracing noise) you get. I always say that the minimum amount of passes macro scenes require is 8, but in this scene I used 15, since – based on the low-resolution test renders – I didn’t expect a very long render time.

Just a little tip for rendering Depth of Field: when you’re ready with the camera settings, run a small test render with less passes (like 5) to see if the focus is in the right place or if the amount of blur is right. For example, I started running test renders with 5% blur, which turned out to be too much. Even 2% seemed a bit much, so eventually I rendered the scene with only 1% blur.

 

Post Render Options:

Just a few words about these settings as well: I never use auto-exposure, because it distorts the way your settings really work in your scene, so I disabled it. I used the default Vue Exposure Filter with the exposure set to 0, Natural film response enabled. I also used a drastic Lens glare with a radius of 83% and an amount of 57%. This gives a really nice glow effect to the final image output.

After saving the image, I made some minor corrections in Adobe Photoshop CC’s new Camera Raw Filter (I really love that!), added some particles and a little bit more drama in Filter Forge 4 (Dreamy and Pixie Dust filters), and finally I framed the image with Film Frame, also in Filter Forge.

Well, that was it! I hope you enjoyed reading about how I made this romantic slimy scene. Happy Rendering! 

Drea Horvath




 
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