TG Blur Reflect

PARAMETERS

Listing :

  Blur Amount
  Blur Steps
  Blur Step Fade
  Overall Reflection Strength
  Contribution
  Blur Directions (Left, Right, Up, Down)
  Strength of Fresnel Effect
  Fresnel Angle
  Fresnel Blend

Blur Amount

Range : 0 to 10

Controls the separation between the maximum shifted blurred reflection and the ordinary reflection. A higher value means that the blurred reflection is shifted further from the ordinary reflection. This will give a greater blur, but will usually require more Blur Steps in order to look convincing.

Blur Amount 0.2

Blur Amount 0.2

Blur Amount 1

Blur Amount 1

Blur Amount 2

Blur Amount 2

Sample spheres showing how Blur Amount affects the spacing of the reflections. Here, a simple red cube is being reflected. Only 1 blur step is used, with a Blur Fade of 1 (so that the shifted reflection has the same intensity as the initial reflection), and some Fresnel settings were applied to darken the reflection ( so that the sphere itself is visible against the background). These images also give a good  illustration as to  how the shader achieves its effects.

Blur Steps

Range : 0 to 10

Sets how many reflections are generated between the conventional, ordinary reflection and the maximum shifted blurred reflection (as controlled by Blur Amount). The higher the value of Blur Steps, the more “in between” reflections are calculated, so the smoother the result, but at the expense of a slower render.

For low values in Blur Amount (of 0.4 or less), a Blur Step of 1 may be all that is required.

Blur Steps 2

Blur Steps 2

Blur Steps 3

Blur Steps 3

This render uses exactly the same settings as the previous Blur Amount 2 render, but varying the Blur Steps from the previous value of  1 - note the extra reflections that appear with each increase in the Blur Steps parameter.

Blur Step Fade

Range : 0 to 1

Each of the shifted reflections takes it strength as being a certain percentage of the previous reflection, so that each shifted reflection gradually gets weaker. With a Blur Step Fade of 0.8, for example, the first in-between reflection is 0.8 times as strong as the conventional reflection; the next reflection calculated will be 0.8 times as strong as the second reflection - ie, 0.64 times the strength of the conventional reflection - and so on.

Note that at a value of 1, each reflection is given equally priority (each is as strong as the other), and there is no fade toward the outer edge of the blur.

Blur Step Fade 1

Blur Step Fade 1

Blur Step Fade 0.5

Blur Step Fade 0.5

Blur Step Fade 0.3

Blur Step Fade 0.3

Illustration of the effect of Blur Step Fade (using Blur Amount of 2.5, and 2 Blur Steps). As the Blur Step Fade is lowered, each successive reflection has a weaker effect.

Note that because of the way the shader adds the reflections together (to ensure that the overall effect doesn’t get brighter with increasing Blur Steps), lower Blur Step Fades here result in a brighter initial reflection of the cube - this is because the red of the cube is being mixed with the grey background picked up from the shifted reflections, and with lower Step Fades, the strength of the grey background added in is lessened, leaving the initial reflection a brighter and stronger red. This is less of an issue with smaller (more sensible!) Blur Amount values, but it is worth noting in these examples, and bearing in mind when you use the shader.

Another thing to bear in mind that the Step Fade value may need to be increased as the number of Blur Steps is increased. For example, if you note the right image above, the final reflection is almost invisible, and any further Blur Steps would result in reflections which were not significantly visible, increasing render time for no visible effect - a higher Blur Step Fade would keep the outermost reflection more visible even with more Blur Steps.

Overall Reflection Strength and Contribution

Range : RGB values

These are the usual controls for reflection. The overall strength sets how bright the reflection is (can be set to greater than 1, since it is intended for use as a layered shader), while the contribution controls how many “reflections of reflections” are taken into account. A higher contribution value means more accurate results, but at the cost of a slower render.

Blur Directions (Up, Down, Left, Right)

Range : On or Off

These values let you set how the blur is calculated. The shader works by taking the initial reflection, and bending that reflection in any or all of 4 directions, namely Left, Right, Up or Down. You can get faster (although less accurate and less interesting) blurs by only using one or two of these, and this can quite often be all that is necessary to soften up a reflection and make it look more natural.

In order to let you choose between accuracy and speed, the shader lets you activate each of the blur directions individually. Note that for each direction you enable, a whole set of raytracing calculations is added in, thus slowing down the shader and resulting in a longer render time. Each direction uses the same global parameters (Blur Amount, etc) to calculate the shifted reflection .

Right only

Right on its own

Left and Down only

Left and Down

Renders with only some of the directions selected.

As with the Blur Step Fade examples, note that the extra direction adds in “more grey” to the reflections of the cube, resulting in a less intense red colour. The reason behind this is the same as for the Blur Step Fade examples.

Fresnel Reflect Effect Strength

Range : 0 to 1

At a value of 0, no Fresnel effects are seen in the reflection - the reflection is of a uniform intensity across the surface of the object. At a value of 1, the full effect of the Fresnel calculations are seen, with the maximum variation in intensity of reflections across the surface of the object, depending on the angle between the viewer and the surface.

Fresnel effects are applied after adding up the initial and shifted reflections, so will affect the overall strength of the final reflection.

Fresnel Angle

Range : 0 to 1

Controls where the reduction in reflectiveness occurs. The fresnel effects calculate a fall off in reflection, so that surfaces angled toward the viewer are less reflective than those angled away from the viewer. This parameter controls the angle at which this effect occurs - a higher value means that only surfaces steeply angled away from the viewer will be reflective, while a lower value means that even surfaces facing the viewer will still be highly reflective.

Fresnel Blend

Range : 0 to 1

Controls how the fade from reflective to not reflective occurs for the fresnel effect. Low values result in a very sudden transition from highly reflective to no reflectivity at all, while higher values will give a smoother blend. Note that the blending happens “inwards” from the Angle, so a higher value will make surfaces which are facing the viewer more reflective.

TG Blur Reflect Intro

TG Blur Reflect Parameters

TG Blur Reflect Tips

TG Blur Reflect Samples

TG Pack2 Index