DriveWorks Pro 24

Specular

Specular - Render Property

The Specular render property uses the same lighting as the default render property but adds further detail to the specular highlight for more realism. The Specular highlight is dependent on the surface angle, light angle and the viewing angle.

The Specular render property lets you add an additional specular texture that defines the specular highlight. This texture determines how light reflects and highlights on the surface of the model.

A Specular Texture defines parts of the surface that might be dirty, scratched or darker. This means that these areas of the surface will react differently to the light source.

Without Specular Texture	With Specular Texture

Without a Specular Texture the light reflects off the surface like it's a flat plane. With a Specular Texture the light reflects off the surface based on the defined texture. The Specular Texture defines areas that reflect light and those that do not.

In this example, we can see the worn tyre marks being defined by the texture. These are the more reflective surfaces of the road.

Setting up an Appearance to use the Specular render property

1. In a DriveWorks 3D Document, navigate to and select an Appearance.
2. In the Information Panel select the Render Properties drop down.
3. Select Specular from the drop down list.
4. Select the Alpha Mode required for images applied to the PBR Advanced render property.

   Alpha Mode allows images with transparency to display any objects or scenes behind them.

   See Alpha Mode below for more information.

Alpha Mode

Alpha Mode allows images with transparency to display any objects or scenes behind them.

For Render Properties, other than Glass, the Alpha Mode can be set to:

• Default

  Will display any alpha in the image as fully visible.

• Cutout

  Will display any alpha in the image as fully visible or fully transparent, depending on the Cutout Threshold.

  • Cutout Threshold

    Set a value between 0 and 255 for the threshold to use to determine the pixels that will be displayed.

Using images with transparency, with the Cutout Alpha Mode, can enhance the DriveWorks 3D model by reducing the need for complex geometry.

For example, the image below:

Can be applied, as an appearance, to a Model.

The gray and white chequered background represents the alpha channel used in the image.

The Alpha Mode settings applied are shown in the table below:

Default	Cutout

Render Property Settings

The settings available on the PBR Advanced render property are grouped into the following categories:

Diffuse Color settings

Sets the color to use for the diffuse color of the Appearance.

Will apply a hexadecimal value to the Diffuse Color in the Parameter Panel.

• Red

  Modifies the amount of red in the Diffuse Color. Enter a number from 0 to 255.

• Green

  Modifies the amount of green in the Diffuse Color. Enter a number from 0 to 255.

• Blue

  Modifies the amount of blue in the Diffuse Color. Enter a number from 0 to 255.

• Alpha

  Controls the alpha channel or transparency of the Diffuse Color. Enter a number from 0 to 255.

  If the geometry wih the Diffuse Color applied is to have Shadow Casting or Edge Sketch applied, the appearance is required to be fully opaque.

  The alpha applied needs to be exactly 255. Anything less than this value is considered not fully opaque.

• Ambient Intensity

  Controls the ambient intensity of the Appearance as a whole. Enter a number.

• Diffuse Intensity

  Controls the intensity of the Diffuse Color/Texture. Enter a number.

Specular Color settings

Sets the color to use for the specular.

Will apply a hexadecimal value to the Specular Color in the Parameter Panel.

• Red

  Modifies the amount of red in the Specular Color. Enter a number from 0 to 255.

• Green

  Modifies the amount of green in the Specular Color. Enter a number from 0 to 255.

• Blue

  Modifies the amount of blue in the Specular Color. Enter a number from 0 to 255.

• Intensity

  Controls the intensity of the specular highlight on an Appearance. Enter a number.

• Reflectivity

  Controls the amount of reflectivity of an Appearance. Enter a number from 0 and above.

Texture Offset settings

• Offset X

  Offset an applied texture in the X Axis. Allows you to position textures accurately on surfaces. Enter a number.

• Offset Y

  Offset an applied texture in the Y Axis. Allows you to position textures accurately on surfaces. Enter a number.

Texture Transforms settings

• Scale X

  Modifies the scale of a texture to suit the size of the model.

  Enter a number from 0 and above.

  See Scaling Textures below for information on how scaling affects the applied texture image.

• Scale Y

  Modifies the scale of a texture to suit the size of the model.

  Enter a number from 0 and above.

  See Scaling Textures below for information on how scaling affects the applied texture image.

• Angle

  Change the rotation of a texture on a model. Enter a number from 0 to 360.

Scaling Textures

The scale of a texture is applied differently when World Position Textures is enabled.

• When World Position Textures is Disabled:

  A scale of 0.5 will stretch or shrink half of a texture repetition over the corresponding axis of the geometry it is applied to.

  A scale of 1 will stretch or shrink one full texture repetition over the corresponding axis of the geometry it is applied to.

  A scale of 2 will stretch or shrink two full texture repetition over the corresponding axis of the geometry it is applied to.

  For example:

  Geometry Scale in the X and Y axis = 0.5 (meters)

  Texture Transform Scale X and Y axis = 1

  Will result in one full texture repetition over the 0.5 meter of the X and Y axis.

  

• When World Position Textures is Enabled:

  A scale of 0.5 will apply half of a texture repetition over a 1 meter length in the corresponding axis.

  A scale of 1 will apply one full texture repetition over a 1 meter length in the corresponding axis.

  A scale of 2 will apply two full texture repetition over a 1 meter length in the corresponding axis.

  For example:

  Geometry Scale in the X and Y axis = 0.5 (meters)

  Texture Transform Scale X and Y axis = 1

  Will result in half a full texture repetition over the 0.5 meter of the X and Y axis.

  

World Position Textures

World Position textures allow seamless texturing over multiple models.

To understand how a World Position Texture is scaled see Texture Transforms settings above.

World Position Textures Disabled	World Position Textures Enabled
The same textured appearance applied to multiple geometries does not flow seamlessly when one of the geometries differs in size.	Enabling World Position Textures allows the same texture to flow into geometries with a different size without the need for complex calculations to scale the texture.

The following parameters can be selected:

Checking each checkbox will add that world position axis value at each pixel's location, to the corresponding texture coordinate value.

This has the effect of making the texture flow along that axis in world space.

• Enabled

  Checking this will enable World Position Textures.

  A rule can also be built for this from the parameter panel by selecting the Enabled (with the address WorldPositionEnabled) property.

• Horizontal
  • X

    Checked by default

    Check to add the horizontal X axis to the corresponding texture coordinate value.

  • Y

    Unchecked by default

    Check to add the horizontal Y axis to the corresponding texture coordinate value.

  • Z

    Checked by default

    Check to add the horizontal Z axis to the corresponding texture coordinate value.

• Vertical
  • X

    Unchecked by default

    Check to add the vertical X axis to the corresponding texture coordinate value.

  • Y

    Checked by default

    Check to add the vertical Y axis to the corresponding texture coordinate value.

  • Z

    Unchecked by default

    Check to add the vertical Z axis to the corresponding texture coordinate value.

Diffuse Texture

• Texture

  Select a diffuse texture from the list of available textures in the Document. Alternatively you can browse for a texture or build a rule to the path of a new texture.

Specular Texture settings

• Texture

  Select a specular texture from the list of available textures in the Document. Alternatively you can browse for a texture or build a rule to the path of a new texture.

Using the Specular render property

The Specular render property can be used in a couple of ways. You can use it with a Diffuse Texture or a Diffuse Color and it will define how the light reflects off that surface.

The result will be a surface of either a color or texture with a specular texture defining lighting highlights.

Diffuse Color and Specular Texture

Simple colors can be applied to the surface of a model. A Specular texture can then be added to give that surface defined specular highlights.

Adding a Specular texture to a surface gives it more realism and makes it look like a real surface without defining a Diffuse texture.

Because we haven't defined a Diffuse texture, you have the ability to drive and configure the Diffuse Color. This means you can dynamically control the Appearance whilst maintaining realism.

Diffuse Color without Specular Texture	Diffuse Color with Specular Texture

Using a Diffuse Color and not a Diffuse Texture, means that you can configure the color through Rules in DriveWorks. You can configure the color and still use the Specular Texture to make the surface more realistic.

Diffuse Texture and Specular Texture

A Diffuse Texture can also be used with a Specular Texture. The Diffuse Texture can be used instead of Diffuse Color.

A Diffuse Texture can define the detail of a surface. This could be a complex wood grain or complex surface pattern. The Specular Texture will then add realistic light to that surface that matches the diffuse texture.

Diffuse Texture without Specular Texture	Diffuse Texture with Specular Texture

The Diffuse Texture helps to define the base outline of the texture. The Specular Texture then adds to that by accurately defining how the light interacts with the surface.

If you compare the Diffuse Color with Specular Texture against the Diffuse Texture with Specular Texture then you should see clear lines defined around each concrete square.

Specular Texture - Alpha Channel

It is recommended to use a PNG for the Specular Texture. A PNG supports an alpha channel. The alpha channel in the PNG image is used for reflectivity.

When the image has an alpha channel the result will be used to enhance the reflectivity of the model. Transparent areas will result in a low reflectivity and opaque areas will result in the same reflectivity as specified on the Appearance.

Specular Texture Examples

Other Render Properties

DriveWorks has other render properties available to use on an Appearance.

These add different levels of realism to an Appearance.

• Default
• Bump
• Emissive Bump
• Reflective
• Glass
• PBR
• PBR Advanced