Dissertation fragments: part 3 – Elements in Maya

Light types in Maya surface:

In the real life there is not only one type of light. This changes depending of the issuer (the sun, a lamp, a reflector…). To be able to simulate all this variety in a digital surface, it were created a different types of light that are equal in all 3D software although they are named in different ways depending on each one. In Maya they have the following names: Point Lights, Spot Lights, Directional lights, Ambient Lights, Area Lights and Volume Lights:

–          Point Light: Simulate punctual light rays to infinite directions in a homogeneous way.  Light bulbs or other little light generator can be simulated using point lights, although in the real world any light generator is 100% omnidirectional. To do this there are some techniques as decide if they should cast shadows or not.

–          Spot Light: They illuminate a cone shaped area. Spot lights are punctual too but the difference between them and Point lights are that Spot don’t illuminate equally in all directions. The artist can limit the influence area and the softness of the light borders in order to create different sizes and transitions between light and shadows. They are the equivalent of the theatre or automobiles lighting.

–          Directional Light: This kind of lighting is not punctual. Once you use it parallel light beams appear in the direction you choose. In this kind of light you can’t control the proximity of the light issuer, only the direction of the light rays manipulating the rotation controller. It’s used to simulate sunshine ambient or to be part of the secondary lighting in a light set.

  • There is a particular direction light no able for Maya Software named Physical Sun and Sky that recreate in a veridical way the Kelvin colour temperature and the different intensities on sun light in lumens during the day. It’s able to reproduce every time of the day only rotating the light controller. If you put it perpendicularly to the ground it will seem to be mid day, but if you put it to 35º to the ground it will seem to be the sunrise.

–          Ambient Light: It’s used to illuminate indirectly the different objects of your scenario. Its function is to illuminate the parts where are not illuminated by direct lighting and they appear too dark. Using the ambient light, illumination seems more realistic and there is no lack of information. But, this kind of light has some big troubles. It’s difficult to obtain a good control of it and it hasn’t a nice quality in shading, so it is criticised by the amount of professionals who have searched some better alternatives.

–          Area Light: These are lights underused because of his large rendering time. They are used to project lights and shadows to simulate the light what pass through a window. It has an excellent shading quality but is used only with still images in info architecture.

–          Volume Light: This kind of light has the advantage that you can know which volume the light influence has, because the only that will be illuminated is all which is inside of the influence sphere. You can configure if you want a punctual or a directional light, and this is another advantage of the light.

Shader types in Maya surface:

There are three types of generic materials: Surface Materials, Displacement Materials and Volumetric Materials. Volumetric ones are used to create atmosphere effects like dust particles, fog or smoke. Displacement ones are used to create deformities in the mesh of an object during the rendering process in order to get wrinkled borders within use too much polygons in its meshes. After that there are surface materials, which give to objects properties to react to the lights and seem to be built with a concrete material. These last materials are the ones that will be mentioned in this dissertation.

Using Maya Render, we realise that we can use the following surface materials: Anisotropic , Blinn, Hair tube Shader, Lambert, Layered Shader, Ocean Shader,  Phong, Phong E, Ramp Shader, Shading Map, Surface Shader and Use Background. Once Mental Ray plug in is activated, 31 new materials appear in the material browser, adding thousands that you can download from internet.

As we see, Mental Ray is a very complete tool than can help us to achieve the material perfection in an easy way, given us dozens of new opportunities.

Mental Ray materials have been developed to be excellent in a very specific material, so they are less versatile than the default basic surface materials. Because that, they will be analyzed in a different way.

Basic surface shaders in Maya:

–          Anisotropic Shader: This material stretch and twist the reflections of the light depending of the relative position of the user. Is used specially to create hair, feathers and satin materials.

–          Blinn Shader: Calculates brightness depending on the surface curvature, the amount of light and the angle of the camera. It reflects brightness and materials of his environment and it’s very accurate. Is used to reproduce metallic surfaces like aluminium.

–          Lambert Shader: It’s a monotone material that produces a soft lighting effect with no brightness. It’s the perfect material to reproduce ceramic or chalk.

–          Phong Shader: It has the same properties than Blinn Material but being more simplistic. It doesn’t reflect brightness or materials of his environment. It’s perfect to reproduce polished bright surfaces ass plastic or porcelain.

–          PhongE Shader: Is the simplistic version of Phong with lower render times.

Advanced shaders in Maya:

–          Layered Shader: Using this material, you can be able to combine different materials to create a complex one.

–          Ocean Shader: It’s used to create simplistic water effects.

–          Ramp Shader: It’s very useful when you want to create materials with different transparency, colour and some other attributes in different parts of itself.

–          Shading Map: Used to get a traditional drawn cartoon effect in a 3D environment. The amount of the Manga based videogames use this material (Naruto, Dragon Ball)

–          Surface Shader: Is used when you want to control transparency, brightness and colour of an object in the time space.

–          Use Background: Apply the background colour to an object.

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Posted on November 20, 2012, in Dissertation. Bookmark the permalink. Leave a comment.

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