Sunday, July 21, 2013

Basic Lighting and Reflection

We would all like a solution where we just take our SketchUp model, click Render and get a great result.

IRender nXt does a surprisingly good job of this for basic exteriors, using the High Dynamic, or Exterior lighting presets.

However, especially for interiors, you need to add lights and set special material parameters - such as reflection in order to get a good rendering. This article will help you learn how to do this.

Basic Model

For these samples, we downloaded a Vanity and a Shower from the 3D Warehouse

Double Sink Vanity
Shower Stall
I placed the vanity in a room in SketchUp and Rendered it.

SketchUp Model

Rendered Model

Adding Lights

The rendered images isn't much better than the SketchUp image.
That is because, especially for interior scenes, you need to add lights and reflections in order to get a realistic image.
First I added some ceiling lights using the IRender nXt Lighting Wizard.

Placing Ceiling Lights

Just these lights improved the rendering significantly.

Vanity with overhead lighting

Adding Reflections

Of course we need to make the mirror reflective. But making the walls reflective will add realistic detail as well.

To make a surface reflective, right click on the material and load the Material Editor:

Making the floor reflective

Rendering with floor, walls and mirror reflective

I used default reflection for the right hand wall the first time. But it was too reflective, so I cut the intensity down from 60% to 40% to make it more subtle.


Reflection and Highlights are similar. Highlights are reflections directly from lights, rather than reflection of other objects. They add to the realism of a scene.

Here I added reflection to everything which might reflect or create highlights.

(See the highlight in the faucet, even though there is not much reflection.)

Reflection and Highlights on Counter

Something to Reflect

Another important consideration is having something to reflect.
In the scenes above with have a reflective mirror, but nothing interesting to reflect.
I added the shower from the 3D warehouse to the part of the room behind the camera, to make the scene more interesting.

Mirror with reflection of shower

Additioan Texture Features

The images above all used standard SketchUp materials.

Arroway Textures

You can get more realistic results by using better materials. For example, Arroway provides a library of textures, (not for free), which have special shading features for more realistic highlights and reflections.

A Wood Floor rendered from an Arroway Texture
Demo boards-001.jpg

These textures can be imported into SketchUp and used with IRender nXt.

Shiny, Blurry and Glossy Reflections

In addition to the amount of reflection on surface, you can also adjust its shininess.
In this example, I made the faucets white ao you could see more detailed reflection.

Faucet with shiny reflection
Bathroom vanity-shiny.jpg

For certain surfaces, like brushed metal, tile floors or wood, the reflection is often blurry rather than shiny. Here I lowered the shininess to 25% (from 100%) to get a blurry reflection.
Blurry reflections require more rendering passes because the blurriness is achieved by using different, random, angles for reflection on each pass.

Blurry reflection-dialog.jpg

Faucet with Blurry reflection
Bathroom vanity-shiny.jpg

Glossy reflection allows the highlights, but no specific reflection of other objects. It is done quickly and does not require additional passes.

Glossy reflection.jpg

Faucet with Glossy Reflection
Bathroom vanity-glossry.jpg

Lighting channels

Another feature which can save time, and make it easy to balance various lights in Lighting Channels.
Here I have added some sconces above the Vanity, and re-rendered the scene

Default Balanced Lighting

Here I have slid the intensity of the Ceiling Lights down to 10%, which makes the sconces much brighter.

Ceiling Lights turned down to 10%

Here I have restored the ceiling lights, but lowered the intensity of the sconces to 10%

Sconces at 10%
You can't appreciate from just viewing this on line how fast and easy it is to balance lighting with slider bars as the light intensities change immediately on your screen.


You can get get good results easily, just by adding some ceiling ligtts and basic reflection to materials. But for even better results, you need to render the model, take a look, and adjust the material parameters and lights to get the effect you want.

Check out our Videos and Tutorials for more information in how to do this.