Similarly to the textured object, light sources can change the color of the light they throw on the basis of the application of patterns textures.

The method for allocating texture patterns to a light source does not differ from that used for an object, however their application can result in obtaining more elaborate effects.

For our analysis we will create a simple scene with the following:

• A plane with a white material
• Three buckets with basic colors (Red, Green and Blue)
• Two light sources, a point light and spot another type

A close rendering would give us similar to the following image:

The choice of colors of objects has not been arbitrary; soil, white, must show the original colors of the chosen pattern, while the buckets, with basic colors, can show behavior in each color channel.

To add textures to a point of light that we must select modify and enter the edit mode materials. After you select the operating mode, select the icon “Lamp Buttons” to add a new item if not there already.

Then I go into edit mode textures similar to what was done to add textures to objects, Via icon.

For the case study we are developing will use a wood texture (Wood) we have already used above.

The basic pattern consists of parallel strips provide us, given its simplicity, analysis of the results of each change we make to the system.

In the preview window see active button “Lamp” indicating that we are changing a light spot.

Return to editing the material selected (point lighting) with work mode associated, we will use the icon again “Lamp Buttons”

The selected texture can be modified to change their application in several respects:

• Color properties of texture
• Application to light or shadow of the object
• How the lighting is mixed with the colors of the object.

For our analysis we have opted to choose a basic color, red, keeping the rest of original parameters to the default.

If we render the scene ( pulsing F12 ) see that on the object that has the same color as that texture (red) its effect is not seen, if the object enhances the color intensity of the areas illuminated by the light spot.

The white floor however shown colored with texture but are softened by adding the second illumination light spot; other color objects reflect increasing its illumination part according to the chosen pattern.

Textured shadows

The shades thrown by objects have behaved identically to the case studies with a conventional white light. Just missed illumination intensity in the affected areas, namely, on which the light is incident directly.

Texturing of light can affect the shadow cast by impinging on an object. To activate this effect lighting simply click on the button “Shadow” that is in the flange “Map to” referred to above.

In the following example both are enabled applying texture to illumination, as the material.

In the left part of the picture you can see the effect of “coloration” Shadow texture applied according to. To view the image in detail selected with the mouse.

Of course you can only sombran textured disabling the button “Cabbage” in the same menu.

The point of light will behave in this case, with respect to the direct illumination of the objects, as if it were textured, maintaining the application of the texture on the shadows of objects.

Texture Blending Mode

One of the most complex aspects of control is the way the light is mixed with the colors of objects on the incident.

There are different forms of “mix” colors, affecting the color channels of the materials. By choosing one way or another we will see very different results based on the rules of operations with images known as Porter-Duff rules, within the model or technique “Alpha compositing”.

The different options available in the Blender software, are displayed for your selection from the menu above lighting setup.

Not go so far in detail in the analysis of each of these images blend modes, but visually we will glance through some examples to more differentiated. The reader is left as an exercise basic comparative discussion of these examples, as a form of introduction to the topic.

Add

Color

Darken

Difference

Multiply

Finally we use a texture with different colors to see the effect of a more elaborate.

Remove the light spot “omnidirectional” found at the scene and keep the type “Spot”. The intent is to appreciate the contribution of illumination light in isolation, to observe in detail their impact on the scene.

A texture-based “Voronoi diagrams” can serve perfectly for our purposes.

Selecting texture will edit the timber changing (Wood) used in the previous cases for the option “Voronoi”

The result is shown in the following image you can see the contribution that occurs on the white floor in contrast to the effect produced on the faces colored, appear to behave as if they are filters which remove color components; is monochromatic to reflect only the corresponding color.

• Image Synthesis

Tutorial made for version 2.49b

External Links

• Color (Wikipedia)
• Lighting Wiki blender)
• Textures (wiki blender)
• Textures: Types and Options

Blender Tutorial