HDRI 3D Xtra!

XTRA!

			Radiance Effect with Gradients
			BY GERARDO ESTRADA

Overview - Modeling - Surfacing & Texturing - Gradients - Download Objects & Scenes

Gradients

Figure 1

Let's begin with the gradients' structure. The input parameters that are necessary for this effect type (figure 1) are:

Distance to object

For this gradient type, the first gradient key represents the position of our reference object and the starting point of the gradient; this means that the subsequent parameters will be applied farther and farther from the distance of our object reference. The behavior of this input parameter is omni-directional (like the shock wave of an explosion) (figures 2-4).

Figure 2

Figure 3

Figure 4

X distance to object

The first key on the gradient represents the position of our reference object and the starting point of the gradient that will be applied to it in the X-axis only, according to world coordinates (figures 5-7).

Figure 5

Figure 6

Figure 7

Y distance to object

The first key on the gradient represents the position of our reference object and the starting point of the gradient that will be applied to it in the Y-axis only, according to world coordinates (figures 8-10).

Figure 8

Figure 9

Figure 10

Z distance to object

The first key on the gradient represents the position of our reference object and the starting point of the gradient that will be applied to it in the Z-axis only, according to world coordinates (figures 11-13).

Figure 11

Figure 12

Figure 13

Note: The gradient will spread in the same way in both directions in the X-, Y-, or Z-axes, taking as the starting point the object reference (in other words, the point corresponding to 0,0,0 when the object is viewed in Modeler). Using the "Distance To Pivot" Input Parameter would use the Pivot Point of the object, which is generally 0,0,0, but may have been modified in either Modeler or LightWave Layout.

In these examples we've used the luminosity channel, but these parameters are applicable to any channel.

Keeping all this in mind, we add a Null object, rename it as a sphere, and position it as in Figure 14.

Figure 14 (Click for larger image.)

Then, to simulate the light that bounces from the table toward the sphere and is scattered inside it, we add a gradient based on this null object (sphere) in the luminosity channel (figure 15).

Figure 15

The graphic representation of this gradient would be as in Figure 16.

Figure 16

The first parameter (black) represents our null object position, and the second parameter (orange) is to maintain the brightness intensity the necessary distance until the sphere. The third parameter (yellow) is the necessary distance to vanish the brightness along the sphere diameter; we can do this by diminishing its value at 0% or by diminishing Alpha at 0%.

Tip: Diminishing Alpha is especially useful when we use gradients in the color channel, since it permits us to blend gradient color with base color or texture.

Overview - Modeling - Surfacing & Texturing - Gradients - Download Objects & Scenes