Friday, April 13, 2012

Objectivity, Part 1

Today, it's back to basics time!  In this post, I'll talk about Second Life objects.  I'll say more about them in some future posts, too...but this will not be a complete course in Second Life building by any means.  For that, you should start with the great self-paced tutorials at The Ivory Tower Library of Primitives.

Second Life objects are (with two notable exceptions) made up of "prims," which is short for "geometric primitives".  These are basic shapes like a box, a ball, or a donut (torus).  They can be stretched, squashed, cut, tapered and twisted in various ways, textured with images, and linked together to form all the things you see in Second Life.  They are created using the in-world building tools. 

The two exceptions are:

1.  Sculptured prims (sculpties).  A sculpty is an ordinary prim (most start out as spheres, but they can also be a torus, cone, or plane).  A special texture called a "sculpt map" is applied to the prim.  The color values of this sculpt map (Red, Green, and Blue, with possible numerical values from 0-255) are used not to color the object, but to tell your graphics card how far to move the vertexes of the base object from their starting positions.  This makes the sculpty look (on your screen) like an object with an organic shape...a pretty high heeled pump, or a gnarled tree branch or a boulder, for instance.  Sculpties are usually made Phantom because, while the object may look like one thing, Second Life uses the bounding box of the original, un-sculpted object for purposes of figuring collisions.  Sculpt maps are created in third party programs such as Blender, Sculpty Paint, Rokuro, Wings 3D, Maya, or LightWave 3D...any program which allows the creation of "UV weight maps".

2.  Mesh objects.  Mesh objects are fairly new to SL.  Instead of primitive shapes, a mesh object is made up of many triangular or four sided 2-dimensional polygons.  Meshes are created with third party programs.  Any 3D modeling program which will export your work as a Collada (.dae) file can be used.  Depending on its size, level of detail, and whether it contains scripts, a Mesh object may have more or less land impact than the same object made out of ordinary prims.  Mesh can only be seen correctly with newer, "mesh enabled" Second Life viewers.  If you use an older viewer and look at mesh, you will see a collection of balls and toruses.

The Build Window.  This is the place where you play God and create things from thin air.  Go to a sandbox, or anywhere else you can rez objects.  Right click the ground, select Build (or Create, depending on your viewer).  The mouse cursor changes into a magic wand.  Left click it on the ground, and phwooosh!  a plywood cube appears.

Congratulations!  You are now a Second Life Content Creator.  Next time, I'll talk about some of the settings in that Build window.  But until then, have some fun exploring them for yourself, and see what you can do to that poor innocent cube.

1 comment:

  1. One concept that confuses building newbies is "texture". The natural interpretation is that is surface bumpiness. Newbies are often surprised to learn that it is more like the wallpaper you paste on the surface of a prim.
    You do a great job of teaching the basics, I have sent newbies to your blog several times.