Current stable version: 0.1.1

Interior Lighting: Products

Introduction

In this tutorial, we will see different possibilities to light objects in a room, a closed environment.

Which lamps to work with, the different light rigs, and effects such as reflections, caustics, Depth of Field or

volumetrics to enhance the quality of your work.

 

 

The environment

The environment is pretty simple because it should be merely invisible to emphasize the interest on the product.

The product is placed on a floor, but a special one, the floor is associated with a wall, shaping a curve. This idea

comes from a real photographer studio set, creating a fake infinite environment and to avoid shadows on the

background.

Studio set, with a rounded floor

An example of a studio set (see how the floor and the wall of the background make a rounded shape).

 

In Blender, let's model a simple rounded floor like this one. Add a mesh > plane, and scale it on the

X axis (S, X). In Edit Mode, select the edge at the background and extrude it on the Z axis (E, Z).

Floor

We have our basic shape, now let's make it rounded. Add a Subsurf Modifier to this plane with Levels and Render

Levels at 3. In Edit Mode select all the edges but the central one (the only one shared by the two faces) and crease

their subsurf at 1 (Shift-E).

Floor rounded

Wonderful. Don't forget to enable Set Smooth for the plane.

In the same time you can assign it a default Yafaray material: a white shiny diffuse.

How? In Blender select the plane, add a material and call it “Floor” for instance. Back in Yafaray

GUI, in the material panel, select the material Floor and let the material by default.

Floor material

 

 

Which method of Lighting?

For an indoor scene, it's more efficient to use Photon Mapping technique. Path Tracing will take more time. You can

use Direct Lighting at the beginning for fast renders, when you're working on the lights and choose Photon Mapping

at the end.

 

 

The lights

Area lamps

The scene is an indoor studio, so we don't need Sun here if there is no windows in the room, obviously (of course,

if you really want to use one, you can, these are just suggestions). Here we are using Area lamps. Area lamps are

a great choice to produce a dim light with soft shadows. Their size changes their intensity and the softness of the

shadows. Be careful: the energy of area lamps in Blender and Yafaray is different. In Blender, an area lamp with

Energy=1 gives a strong light. In Yafaray, you could use an Energy=4 (in the Yafaray GUI) to have a soft light.

To change the size of the Area lamp, use the size parameter in the Lamp panel, within Blender, don't scale them

in the 3D view. You can shape them as a rectangle or as a square.

 

Mesh light

If you want to use a different shape than a square or a rectangle, you can use a mesh as an area light. It's called

mesh-light and it has the same parameters (color, energy, samples) than an Area lamp with Make Light Visible enabled.

Note: A mesh light casts light according to its normal. The normals of the meshlight should point towards the objects you

want to illuminate. If the meshlight is at the center of several objects to light, you have to enable Double sided.

 

 

Light rigs

A neutral one

A basic rig to light your scene is to use three lamps of the same properties. Here, three Area lamps or three Planes

acting as Mesh Light. One on the right, one the left, and the last one on top of your scene.

Placement of the area lamps

All the three Area lamps share the same settings: 

Area lamp

A low power at 1.5 (it's enough if there are three lamps), their size (X=4, Y=3), 16 samples for a less grainy render and

Make Light visible to see them reflected.

The settings of the render may change according to your scene. Here, what's important, is the high value for the RayDepth

because of the diamonds objects. The quality of the render is correct with theses settings.

PM settings

Note: Gamma and Gamma Input values are 1.8 because screen captures were done on the Mac version of Yafaray.

If you're working on a PC, the default values are 2.2

We can render the scene, made by Fine. You can find more informations and download the scene in this thread.

Neutral rig render

This technique of illumination is suitable for industrial products, cars, etc, because it's homogeneous. The point of interest

is on the products, in an absolute way.

 

Three point light

The three point light technique is a very common way to light objects or people. It's more efficient to shape the volumes,

emphasizes an atmosphere than the previous method. Technically, it's composed of three lights: Key, Fill and Rim.

The Key light is your main light, the brighter, placed on the side of what you want to illuminate. The Fill light is placed

on the opposite side, it softens the shadows of the Key light. The Rim light is placed behind, to add some details and to

separate the object from the background.

Let's compare a single light located in front of a face (left), and the same face illuminated by the three point light

technique (right):

Walties

With this head of Walt Disney (provided by David O'Reilly), you clearly spot the differences: on the left, the contrast

between shaded and lighted parts is huge, and the volume is flat. On the right, the result is softer, we have a better 

definition of the shapes. Furthermore, lamps are tinted differently which is great to work on the mood.

Three Point Light

Here is the position of the three lights. Now let's see how each lamp lights different parts of the scene.

Key light only

Here, only one lamp is used: the Key Light, an area lamp (size = 3, Power : 4.0) with a orange color.

We use Photon Mapping, so even the dark parts are not too black, thanks to the Global Illumination. The 

Key Light provides a soft light, but the shadows on the left are quite important. We will reduce it with the help

of the Fill Light.

Key + Fill lights

The Fill Light, placed on the opposite side of the Key Light brings some brightness on the left. Shadows are still here

but not as dark as the previous render. This Fill Light is tinted in blue, which is almost the complementary color of the

orange Key Light. This gives a richer mood to your picture.

You can notice that the top of the head and the background are quite similar in color and brightness. We will use a Rim

Light to have a better definition of the elements.

Key + Fill + Rim light

The Rim light have softened the background and brings back some light and color on the top of the head and the plate.

The Rim light is an a area lamp (size = 3, Power = 2, orange color).

 

These two techniques are just examples, of course you could add as many lamps as you want or change their position.

No need to have hundreds of lamps (especially with Gobal Illumination) the point is to think before at the mood you want

to work on and what do you want to achieve.

 

 

Reflection

The important thing to remember when you want to add some reflection is that you should think at what will be

reflected, i.e. the environment of your scene. With our previous light rigs, it's composed of the different lights,

the floor and the objects. It could be sufficient depending on your scene. In scenes where objects have large

reflected parts, like cars, it is a very important work to do.

The elements that are reflected could be lights or other objects placed on the scene. For lights, it's better to use

Area lamps of big size, with Make light visible enabled to see them on the reflective material. Another way is to 

use mesh lights modelled as light sources (doors, windows, neon signs, etc).

No reflections.

Reflections

The method of lighting, materials, lights are the same in the two pictures. But in the bottom one, we have

enabled the Make light visible option and have used some mesh lights. The model comes from Marsupi.

 

If you want to add some details in the reflection, you could use an HDRI map. An HDRI map is a texture that

can be useful to light and as a reflected environment.

 

Use a HDRi map

An HDRI map is an image with a greater dynamic range of luminances between light and dark areas than basic

images formats (.jpg, .png, .tga … ). The formats of HDRI are .exr, .hdr. More details on HDRI can be found here.

If your scene is lit by an HDRI map, you may not want to use additionnal lights. The rings scene made by Fine is

only lit by the HDRI texture.

Where can you find these maps? Here are several good packs of HDRI textures for studio lighting (CC license)

made by Zbyg. Other packs here and there.

How to use them with Yafaray? Back in Blender, add a texture to the world, select one of the .exr files. In the

Texture and Input panel, select AngMap, map the texture to Hori.

 Map to panelTexture panel

Note: I'm using AngMap here because the HDRI is a stretch panorama, but you can find spherical HDRI too. To use this type,

use the Sphere input instead.

Now in Yafaray, in the World Panel, in the Background settings, select Texture and enable Use IBL (for Image Base Lighting).

IBL

You can rotate the texture to change the reflected parts on your object, and its power if your scene is over or underexposed.

Note: If your render is too grainy, increase the IBL samples.

Scene by Fine, with HDRI

This scene has no lamps, the illumination and the reflected environment is provided by the HDRI texture.

Scene made by Fine, no HDRI

The same scene, without HDRI, is lit by 3 areas lamps (Neutral Rig). You can notice the different reflection

and the colder tone of light.


 

 

Caustics

Caustics

Caustics are optical phenomenons when light encounters transparent materials like glass or water. It could be

interesting to use this effect in your scene if you have these type of materials. The best way to have caustics

with Yafaray is to use sharp range lights such as Spots or small Area lamps with a high power. Don't forget

to enable the Make Light Visible option.

You can find other examples of caustics here.

Scene made by MarcoA

This scene, made by MarcoA is a good example where you need caustics to make it more realistic. The scene uses

an HDRI map for reflections. To light, a big area lamp (15x15) with a power of 3 and a small area (3x3, power of 120)

is placed on the right to make caustics more visible.

 

Add some Depth of Field

To make it simple, Depth of Field is the zone where your object is on focus while the foreground and the background

are blured. A shallow Depth of field (when the zone in focus is very short) is more visible when you shoot little subjects.

On a real camera this effect is more important with a high aperture (e.g. f = 1.4) and with a high focal length (telephoto

of 85mm and more).

That's why if you want to use some DoF (and you want that it looks like photoreal) in Yafaray, you have to think at the

lens of the camera and the size of the object. If your object is big (a car for example), the DoF will be large and you

won't see any blur. If you want to focus on a detail of the car, use a high value for the lens of the camera (up to 250mm

in Blender) and play with the value of the DoF wich will be shallow (much blur on the foreground and the background).  

The ring scene rendered with some DoF:

DoF

The lens of the camera is 100mm, the focus object is an empty, placed between the rings.

camera settings

Note: Don't forget to increase the AA samples and passes to obtain a smoother result with DoF.

For more details on the Depth of field, you can check the tutorial of Tungee here.

Complete informations on the DoF here.

 

 

Add some Volumetric

Volumetric is the way to add some smoke, dust or mist. It can be interesting to use in order 

to emphasize the mood of your scene, to make it more mysterious or dirty.

For more informations on Volumetric, check this part of the documentation.

Smoke

Smoke with a firemen's truck. Note how each light scatters in the smoke.

To make this smoky environment, use a big cube mesh where the smoke will be calculated. In the camera view,

increase the size of the cube in order to make its limits invisible for the camera. In Blender it's easier to see

this cube draw with wires instead of surfaces. In the Object buttons (F7) of Blender, in the Draw Panel select

Wire Drawtype instead of Shaded, while your cube is selected.

Mesh volume

You can see here that the mesh is covering a large part of the scene.

Now in the Yafaray GUI, we need to work on two panels: Objects and World.

In the Objects panel, we choose the mesh where the volumetric will be visible. Select your cube,

and enable Volume. We choose the NoiseVolume option to use a texture to define the volumetric aspect.

Mesh object settings

The texture applied to the mesh is a Cloud one, with almost the same settings than the documentation on

Volumetric: NoiseSize at 0.09, NoiseDepth at 6.

 

Now let's move to the World Panel of Yafaray. Select Single Scatter for the Volume Integrator.

Volume integrator

Note: Volumetric is a great way to bring atmosphere to your scene, but it will increase your render times.

Smaller step size will take more time to render.

To test your settings, remember to start low on the AntiAliasing too. Check the documentation part on it.