Understanding Materials

Video: https://youtu.be/LJ6NxpK8qzk

Instructions from video:

Elements in your drawing have materials applied to their surfaces. Every material has finish properties that determine how much the material reflects, emits and absorbs light. These factors can affect the lighting in a rendered scene.

  1. Display a 3D view, then select Edit > Materials Paintbrush, or click the Materials Paintbrush button on any tabbed toolbar.
  2. In the catalog panel, scroll down in the Groups pane and select the Stone Generic group, then in the Materials pane select the Last Chance
  3. Right-click and select Edit Material.
  4. In the Materials Properties dialog box, click in the Display settings details checkbox to enable it. The dialog’s Rendering Effects area expands. Here you can fine-tune the finish properties.

Material Type

Determines the luminance or reflectance of the surface. When you choose a material type, only those settings that apply to that type are available for editing.

Choose one of the following:

Generic. Material used to simulate most surface types. Lets you define each of the available factors (Opacity, Specular, Reflection, etc.) without the restriction of any lighting model.

Diffuse. Simulates a rough or matte material that appears similarly bright from all viewing directions. Suited for materials such as brick or matte paint.

Lambert. Simulates a matte or non-shiny surface with no specular highlights. Ideal for materials such as chalk, pottery, matte paint, or unpolished surfaces.

Phong. Simulates a shiny surface with specular highlights. Commonly used for materials such as polished wood floors, and metals.

Energy Preservation. Refers to the notion that outgoing energy cannot be greater than the incoming energy. Based on the combination of diffuse, opacity, and reflectivity components, this value will adjust automatically as you edit these properties. For more realistic materials, this value should be equal to or less than 1.0.

Diffuse. The color or texture that you want to apply to the material, as seen in 3D rendered or rendered outline display mode.

Enable the Color radio button to display the material in a solid color. Click the color swatch, then select the color you want to use in the Color dialog. Use the slider to adjust the luminance of the diffuse color.

Enable the Texture radio button to apply a texture to the surface. To select a texture or specify texture mapping properties, click the texture swatch to display the Texture Map dialog.

Bump. Simulates bumps and wrinkles through small displacements on the surface. The modified surface is then used for lighting calculations. Perfect for brick, tile anything with a nonflat texture.

To use the texture selected in the Diffuse section as the Bump texture, ensure that the lock icon next to the Bump texture swatch is closed.

To select a different texture to use for the Bump texture, click the lock icon to unlock it, and then select the Texture Map dialog, ensuring that you set the Type to Normal Map.

To control the amount of bump mapping applied, edit the Bump Scale value. A value of 0 means no bump mapping will be applied.

Emissive. The amount of light given off by a material. Click the Color swatch to select the color of the light emitted. Use the slider to adjust the level of emissivity. The more emissive a material is, the more self-luminous it appears.

Opacity. Determines how transparent the material is. Think of this as a mask being applied over the surface. Click the Color swatch to select a color for the opacity mask. Use the Transparent/Opaque slider to adjust the level of transparency. Use the Dull/Glossy slider to specify the glossiness of the opacity mask.

Specular. Reflection that creates highlights on materials, making them appear shiny. Click the Color swatch to select a color for the specular highlights. Use the slider to adjust the intensity of the highlight color. The higher the value, the lighter (and therefore shinier) the color. Use the Dull/Shiny slider to adjust the size of the highlights.

Reflection. Refers to the throwing back of the light by a surface. Used to simulate used to reflective objects like mirrors and shiny surfaces. Click the Color swatch to select a color for the reflected light. Use the slider to adjust the amount of reflection. Use the Sharp/Blurred slider to determine whether the surface reflects the selected color or its surroundings. Note that the blurred effect may increase rendering time.

IOR. The Index of Refraction. This describes the way light bends when crossing the material surface. A value of 1.0 means the light will not change direction. Selecting a material from the dropbox (e.g. Air, Water, Crystal, Glass, etc.) populates the IOR edit box with the Index of Refraction for that material. If you would prefer to specify a custom value, select Custom from the dropbox, then specify a value in the IOR edit box.

Fresnel. When enabled, the reflection strength becomes dependent on the viewing angle of the surface. Some materials in nature (glass, etc.) reflect light in this manner. Note that the Fresnel effect depends on the Index of Refraction as well.

Sphere/Box. Specifies the way the 2D texture is applied to a 3D object. The basis of Sphere mapping is to treat the object as if it were a sphere. A single texture is applied to the whole object, and the texture mapping coordinates are generated based on the angle of the surface at each point. Box mapping creates a rectangular bounding box around the element, then applies a texture to each of the box’s 6 sides. This would be useful for an element such as a sofa.

Editing Texture Mapping Properties

If you are using a texture to represent a material, you can specify several settings that determine the appearance of the texture.

You can access texture mapping properties in the Material Properties dialog, by clicking a Texture swatch.

This displays the Texture Map dialog:

Here you can click Select to choose a BMP, JPG, TGA or PNG file from the Textures directory.

If you are selecting a Bump texture, you must set the Type to Normal Map. Normal mapping is a technique used for simulating the lighting of bumps and dents. The Standard mapping type simply maps and wraps the pixels to a 3D surface.

If you want to change the scale of the texture, enter new values in the Tile Height and Tile Width edit boxes. Tile height refers to the height of one bitmap tile. The program uses tiled rendering to display images, meaning images are generated in pieces (tiles) vertically and horizontally. Changing the tile height of a brick material, for example, would make the bricks look taller. Changing the tile width would make the bricks look wider.

By default, the Tile Height and Tile Width have the Maintain Aspect Ratio lock closed. When the lock is closed, the Tile Width changes to match the Tile Height, and vice versa. This prevents distortion. If you want to specify different values for each, you need to open the Maintain Aspect Ratio lock by clicking on it.

To repeat the bitmap tile horizontally, enable the Tile Horizontally checkbox.

To repeat the bitmap tile vertically, enable the Tile Vertically checkbox.

If you want to make portions of a texture transparent, use a graphical editor to apply a magenta color to those areas that you want to make transparent. Then, in the Texture Map dialog, enable the Make magenta color transparent checkbox.

The Texture Intensity setting lets you control the brightness and contrast of the texture. Specify a value from 0.00 to 2.00.

We hope this Tool Tip helps you moving forward!