Wednesday, September 1, 2010

[DOC-MESH] Materials enabled? How does this work?

Materials enabled? How does this work? Is it optional?


When the mesh package says "materials ready/enabled", it comes with normal and/or specular maps.

Is it a special kind of item? Yes and no.

All objects in SL (even prims, yes) can be "materials enabled". This means that when using special maps called normal and specular maps, and seen with a current viewer that has Advanced Lighting Mode turned on, they will render some detail and effects more realistically.

You can see objects in a non materials enabled viewer, or with the Advanced Lighting Mode turned off. You will not see the extra rendered features, but the object will render correctly anyway.

This means that materials are OPTIONAL. You can use this mesh model without any of the supplied normal and/or specular maps.

If you want to know what normal and specular maps are, and how to use them, then continue reading.

TABLE OF CONTENTS


WHAT IS A NORMAL MAP?

In easy words, a normal map is a texture that tells the 3D engine, SL in this case, how to simulate "bump" detail that would be otherwise too resource consuming (LI and rendering time) if modelled. For example, cracks in walls/floors/rocks/etc. , tiles, cloth detail, skin detail and many more can be added without our mesh having dense geometry that takes quite a while to render, thanks to using normal maps.

If you like the "bump" effect achieved with the provided normal maps, then feel free to use them. You can create your own normal maps to be used with your own textures. You can do this within Blender, or using other tools:

https://developer.valvesoftware.com/wiki/Normal_Map_Creation_in_The_GIMP
https://developer.valvesoftware.com/wiki/Normal_Map_Creation_in_Photoshop_or_Paint_Shop_Pro

How do we use them? That's explained on the HOW DO I USE THE NORMAL/SPECULAR MAP IN SL? section.

WHAT IS A SPECULAR MAP?

In easy words, a specular map is a texture that tells the 3D engine, SL in this case, how to simulate the way the light should reflect over a surface. Instead of having SL calculating the reflections over all the surfaces, which would be very (VERY) resource consuming, SL emulates how the light should reflect if the object provides this information in a specular map.

If you like the specularity achieved with the provided specular maps, then feel free to use them. You can create your own specular maps to be used with your own textures. Following there's a tutorial discussing this for SL:

http://www.lelanicarver.com/2013/05/gimp-texture-normal-map-tutorials-specular-spectacular/

How do we use them? That's explained on the HOW DO I USE THE NORMAL/SPECULAR MAP IN SL? section.

HOW DO I USE THE NORMAL/SPECULAR? MAP IN SL?

In order to use these maps, the first we need is being in a current viewer. When we do this, the Texture tab of the Edit window changes, from what it has been... all the time! (Before materials were introduced to SL.)

Instead of giving us a texture box, to drop the texture we want to texture our item with, it shows the color, transparency, full bright and glow, and below, there's a drop down menu with a "Materials" option, then a texture box plus three options:

TEXTURE (DIFFUSE)
    BUMPINESS (NORMAL)
    SHININESS (SPECULAR)

When we select "Texture (diffuse)", the texture we drop under the "Texture" box will be the texture we'd use to texture our object. When we select "Bumpiness (normal)", the texture we drop under the "Texture" box will be the NORMAL MAP. Finally, when we select "Shininess (specular)", the texture we drop under the "Texture" box will be the SPECULAR MAP.

Check the provided sample object to see how this is done.


I wish this information helps you in using normal and specular maps for your objects in your creations.

-- Auryn Beorn

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