CaZaBa

Home

About

Tutorial

Gallery

Download

Purchase

Contact

Czech

English

Materials

Material setting window - Ambient component - Diffuse component - Specular component - Emission component - Opacity

The materials should be examined on a more complex object, so we create a spring with the following parameters:

  • Body radius: 2
  • Thread radius: 4
  • Height: 15
  • Body Seg: 8
  • Thread Seg: 16
  • Thread count: 2
  • Rotation: 0

This is what the implicit surface of the body looks like after the spring is formed. The default color selects the program itself, randomly, but we can change it by double-click on the Model's color box. For better visibility, turn off the edges display by pressing Render - Faces in the viewport's top left corner.

The object in the design viewport is illuminated by the default light located in the same place as the viewport's camera. You may also want to create separate light in the scene and view the object by rendering to view the object from the opposite (unlit) side. A suitable light type is a point light, which you can place for example on coordinates X = -10, Y = 5, Z = 15, light's diffuse component set to white. If you do not specify a path to the output file in the render setup window, rendering will be done only in the window. We recommend turning off the option Shadow casting in the render setting, otherwise casted shadows will distort light experiments

Material setting window

Model of the spring leave selected and open the material settings window by button Materials . When experimenting with materials, you can see the appearance of the material in the main window without closing the material settings window, but after changing material, you must switch to the main window to have change visible (by clicking on the window header) or just move mouse over the main window.

The Material settings window serves as a gallery of materials that you can assign to objects in the scene. You can create 30 of the materials in the window. You can see a little window with a preview of the resulting material on each row to the left. Following are the elements for basic material settings and several texture squares.

Assign the material to the selected object (or multiple objects) by pressing the Add button. You must also use the button if you change the basic material settings (diffuse color, transparency). Basic material settings are written to the selected object and can be different for different objects even if they use the same material and may even change over one object during animation. In contrast, textures are common to all objects using the material, and can not be changed during animation. If you change any texture on the material, the changes will affect all objects with this material without having to use the material assignment button to the object. To disconnect the material from the selected model use item from the menu Model - Disconnect materials. If the object has not assigned a material, the color of the object during the animation can also be changed by setting the basic color in Model's color. By using of the Clear button in the material window you'll reset the material to its default values - white color and no textures.

Ambient component

Ambient color component is the reflectance (color) of the surface for ambient lighting. Ambient lighting is omnidirectional, ubiquitous light, independent of light sources. Ambient lighting is simulated, for example, by illumination of the environment from the sky, even when objects in the shadow are not completely dark. There is only one source of ambient (omnidirectional) lighting in the scene. Light from this source is modulated (multiplied) by the ambient color of the material, the result is added to the overall brightness of the surface.

In the design viewport, global ambient lighting is set in Tools - Preferences, Design view light - Ambient component. For rendering output, ambient lighting is set elsewhere - in the render settings window, select Ambient light color. However, the Ambient lighting switch must be turned on, otherwise the ambient lighting will be black. Lights created in the scene also have their ambient component, but this component does not apply.

The typical use of ambient lighting is that you set the same color as the diffusion component in the ambient material component. Changing global ambient lighting controls the intensity at which objects are lit on the side facing away from the light source - so that the faces facing outwards are dark but not black. Fine-tuning the color shade of global ambient light, you can control the color accordance of lights and shadows. E.g. use a light source with a slightly yellowish tone on the sun-lit object, but move the ambient light to a blue breeze because the shadows are lit by a blue sky.

Here are some examples of combinations. The emission and speculation component of the material is off (ie. set to black). The first 3 figures show the method of controlling ambient light by adjusting the material's ambient color component as well as the diffusion component of the material, the ambient light is being controlled by the brightness of the global ambient lighting. This method has the advantage that the ambient light of all objects can be easily controlled by one global lighting. For example we can easily change the color of the entire environment. In the fourth picture is used the opposite method - global ambient lighting is set to white, ambient light is regulated separately for each object by changing the ambient component of the material. In this way we can alter the ambient light of each object independently of other objects.

The fifth and sixth figures shows that by commutation the color of the global ambient lighting and the ambient component of material we can achieve the same effect of ambient light. This is because the two components are multiplying theirs color components, so they do not depend on their order. For the same reason, in the seventh figure the black color occurs because there are multiplied color components (0,0,255) x (255,0,0) = (0,0,0). Similarly, in the last figure, by multiplying of the yellow and violet colors we will get red, which is the intersection of both colors: (128,128,0) x (128,0,128) = (128,0,0).

Diffuse component

The diffuse color component is the basis of the object color that determines the reflectivity of light in direct light, ie. on the side facing the light source. The diffuse light from the light source modulates (multiplies) the diffuse color component of the material, the brightness of the result varies depending on the inclination of the wall of the object. As the face diverges from the direction of the rays, the resulting diffused light decreases until the parallel direction drops to zero. If there are more light sources in the scene, the resulting diffusion components are added together.

There is only one diffuse light source in the design viewport, automatically located in the viewport's camera location. The color (and thus brightness) of diffuse lighting is set in the Tools - Preferences window, the Design view lighting - Diffuse component. For rendering output, diffuse lighting is applied either from light sources when there are some created in the scene or diffuse lighting set for the design viewport. For rendering using diffusion components, the Diffuse lighting switch must be turned on in the rendering setup window. Without being turned on, objects are rendered as unshaded.

The diffuse light pattern can be seen when the other color components are turned off - ie. the ambient, specular and emission color component of the material is set to black. As the face diverts, the diffuse light decreases until the faces are completely black. Again, as with the ambient color, the color of the light is modulated (ie multiplied) by the color component. Therefore, for example, the red object lit by the blue light will be black - but we know it too from everyday life.

Specular component

The specular color component determines light source reflections from the material. Reflection depends not only on the sources of light and the angle under which the rays fall on the surface, but also at the viewing angle. When moving the camera it will also move the spot of speculative reflection. For rendering using speculative components, the Specular lighting switch must be turned on in the render settings window.

For a speculative component, we determine not only the color of reflection, but also the coefficient called specular exponent, which is the power with which the reflection is concentrated in one place. The higher the value, the smaller the reflection's diameter is.

Specular reflection creates the impression of body surface quality. Matte surfaces do not have a speculative glare (set the color of the specular component to black). Metallic glossy surfaces have a large diameter glow (the speculative exponent is set to a low value), the color of the reflection corresponds to the color of the light. The plastic glossy surfaces have a small diameter, the reflection's color is close to that of the body surface.

Matte surface without reflection:

Metalic surface:

Plastic surface:

Emission component

The emissive color component represents the material's own emission. In fact, it is not a true light emission, the object of its surroundings is not lit. It is only the appearance of an object that has a surface without a light source. Emission light is similar to ambient light, but it is not dependent on any light source. The emissive color component simply adds to the resulting color of the material.

For rendering using emissive components, the Emissive lighting switch must be turned on in the render settings window. In the design viewport, the emissive component is not calculated.

Opacity

Opacity specifies the opacity of the material, that is, the object overlaps the other objects behind it. Opacity is entered in percent, ranging from 0 to 100. 100 represents an opaque object, 0 is a completely transparent object (and therefore invisible). The opposite of opacity is transparency = 100 - opacity.

In a design viewport, when working with transparent objects, it can happen that you may not see the object behind a transparent object or artifacts appear, as in the case of a spiral in the first image. This is because, to accelerate rendering in the viewport, the parts of a scene are rendered sequentially, without the in-depth sorting of the rendered elements (the rendering order usually corresponds to the order of creation of objects). And because you can not draw a distant object behind a close-up object already rendered, these errors occur. This issue only applies to view in the design viewport. As you can see in the second image, this deficiency does not occur when performing main rendering because the transparent elements are drawn in the correct order, with depth sorting.

<< Return to topics

Copyright (c) 2013 - 2019

General terms and conditions

End user license agreement