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Tutorial Requirements
You will need to have some basic experience
with Blender
and, of course, the following pieces of software:
You will also need a .hdr image. A few examples can be
found here.
Introduction
In this tutorial we are going to create an image that uses HDRI technology
- the aim of which is to teach you how to use HDRI sources in Blender. The
acronym HDRI is short for 'High Dynamic Range Image', and is
explained in more detail
here - the practical examples themselves are well worth your browsing time.
Building The Scene
We will start this tutorial by building a simple scene
consisting of four objects - a UV sphere, a lamp, a camera, and a floor plane. Place the objects in roughly the same positions as the diagram
below.
Fiddle with the camera a little until you can render a sphere resembling the one
below. Our scene is now ready. Define the shader of our sphere and adjust
the world settings so that the .hdr image is mapped onto the surface.
Creating the UV Sphere Shader
Select the UV sphere. Go to the editing tab and click on the set smooth button
- This will
automatically smooth out our UV sphere when it is rendered. Now click on the shading tab
and press the add new material button. We want to eliminate the
material's specularity, so adjust the spec slider to 0. Click on the
mirror transparency button and then the ray mirror button.
Set the corresponding slider to a value around 0.50.
Our material preview should
show a texture reflecting a chequered floor plane. We have now finished creating a material for our sphere. If we render our image, we can see it is reflecting a blue colour, which is our
current sky colour.
Loading a .hdr image Into World Settings
Deselect
all objects and click on the shading tab, and then the world settings
tab. From the bottom right of the screen find the add new texture button
and click it. We can now load our .hdr file. To do this, click on the texture tab,
and set the property in the texture type box to Image. Navigate your way through your pc’s
hard drive, until you find your hdr file and then load it up. Leave all the
other settings alone. Soft shadows
To give our scene more life-like
lighting we are going to enable soft shadows. Start by selecting your lamp, then click on the
shading tab. Now click on the lamp button and then on the buffer shadows
button. Play with the settings to your heart's content until they suit your
own individual tastes. You can also adjust the strength of the light in the shader tab.
Final touches
If you are unsatisfied with the results that you receive from your renders, just start moving the light source into a position that you find
more aesthetically pleasing. I also find that if I decrease the amount of diffusion on my
UV sphere, the specularity reduces accordingly as well.
Rendering
Go to the render tab. Make sure that you have YafRay enabled as the render engine,
and that the envmap setting is enabled. Then just hit the render button. The result should
resemble the image below.
This is, of course, only a single example of the potential uses of HDRI mapping.
You could use this feature on any model that you have created, and the technique
is universally exciting, capable of making all your models substantially more
life-like. So play around a bit and watch your renders come to life!
- Tutorial written by Milkdrop
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