Introduction to Building - Working with Primitives

Lesson 1: The Foundation - Rezzing and Manipulating Your First Prim

Theory: What is a Primitive?

In the universe of OpenSim and Alife Virtual, a primitive (or "prim" for short) is the most basic building block available. It is a geometric shape generated by the world's server that you can manipulate in real-time. Everything you see that isn't an avatar or terrain is likely made of one or more prims. There are eight standard prim types you can create:

• Cube (Box)
• Sphere
• Cylinder
• Prism
• Torus
• Tube
• Ring
• Sculpted (A more advanced type we'll cover in BLD-202)

Our focus today begins with the humble Cube, the most versatile prim of all.

Step-by-Step Instructions: Creating and Editing Your First Object

First, find a place where you are allowed to build. In our school, this will be the designated "Sandbox" area. If you see a "no-build" icon (a cube with a red circle and slash) when you hover your mouse over the ground, you can't build there.

1. Open the Build Menu: Right-click on the ground and select Build from the pie menu. Alternatively, you can click the "Build" button on the bottom toolbar of your Firestorm viewer (it often looks like a set of building blocks or a magic wand). This will open the Build/Edit window.
2. Select a Prim Type: In the Build window, ensure the "Create" tool is active (the magic wand icon). Click on the Cube icon to select it. Your mouse cursor will change into a magic wand.
3. "Rez" Your Prim: "Rezzing" is the term for bringing an object into the virtual world. With the magic wand cursor active, click once on the ground. A default-sized plywood cube will appear where you clicked. Congratulations, you've just rezzed your first prim! The Build/Edit window will now be focused on this new object.
4. Explore the Edit Window: The Edit window is your command center. It has several tabs. We will start with the Object tab.
5. Positioning Your Prim: In the Object tab, you'll see fields for Position (X, Y, Z). These are the object's coordinates in the virtual world region.
   • X: East/West position
   • Y: North/South position
   • Z: Altitude (Up/Down)
   You can type new numbers into these fields and press Enter to move the object precisely.
6. Resizing Your Prim: Below Position, you'll find Size (X, Y, Z). These fields control the prim's dimensions in meters. Change the Z value to 3.0 and press Enter. Your cube will become a tall column.
7. Rotating Your Prim: The Rotation (X, Y, Z) fields control the object's orientation in degrees. Try entering 45 into the Z field to rotate it on its vertical axis.
8. Interactive Manipulation: While typing numbers is precise, it's often faster to edit visually. In the Edit window, check the boxes for Move, Rotate, or Stretch at the top.
   • Move: Red, green, and blue arrows appear. Click and drag an arrow to move the object along that axis.
   • Rotate: Red, green, and blue rings appear. Click and drag a ring to rotate the object around that axis.
   • Stretch: White corner handles and colored face handles appear. Drag a white handle to resize proportionally. Drag a colored handle to stretch along that axis.

Key Concepts to Remember

Rezzing: The act of creating an object in-world.
Prim: A single, basic geometric shape.
Edit Window: The main interface for modifying objects.
Axes (X, Y, Z): The three dimensions that define position, size, and rotation. Red is X, Green is Y, Blue is Z.

Lesson 2: Building Complexity - Linking, Texturing, and Advanced Shaping

Now that you can command a single prim, it's time to learn how to combine them into more useful forms and give them a distinct appearance. This lesson is about creating objects that are more than the sum of their parts.

Linking Prims into a Single Object

A single object can be made of many prims. This is called a linkset. Linking turns multiple prims into one object that can be moved, rotated, and copied as a single unit. The last prim you select before linking becomes the Root Prim, which is the "master" prim of the linkset. Its position and rotation define the object as a whole.

1. Rez two or more prims near each other.
2. Click to select your first prim. It will be highlighted with a blue outline.
3. Hold down the Shift key on your keyboard, and then click on your second prim. Now both are selected. The first prim you selected has a blue outline, and the second one has a yellow outline. The one with the yellow outline will become the root prim.
4. With multiple prims selected, go to the Tools menu at the top of your screen and choose Link, or simply press the shortcut Ctrl+L.
5. Your prims are now a single object! Try moving or rotating it. To unlink them, select the object and press Ctrl+Shift+L.

Applying Textures and Colors

A plywood world is a boring world! The Texture tab in your Edit window is where the magic happens. It allows you to change an object's surface appearance.

1. Select your object and go to the Texture tab in the Edit window.
2. Color: Click the white box next to "Color." This opens a color picker. Choose any color to apply a tint to the entire object.
3. Texture: Click the box that says "Texture." This opens your inventory. Find a texture (Alife Virtual provides a library of free starter textures) and click "OK." The texture will be applied to your object.
4. Mapping & Sizing: Below the texture, you'll see fields for Repeats (Horizontal/Vertical Scale), Offset, and Rotation.
   • Repeats: Controls how many times the texture tiles across the surface. A higher number makes the texture pattern smaller.
   • Offset: Nudges the texture's position on the surface without resizing it.
5. Materials & Effects: You can set Shininess (None, Low, Medium, High) to make surfaces reflective, and check Full Bright to make an object glow, unaffected by world lighting.
6. Select Face: At the top of the Texture tab, you can check "Select Face." Now, when you click on your object, you'll only select a single side (face) of a prim. This allows you to apply different textures, colors, or materials to different faces of the same prim! This is essential for detailed building.

Advanced Prim Shaping

Go back to the Object tab. You'll find a set of powerful parameters that can drastically alter a prim's shape.

• Hollow: Give this a value (from 0 to 95) to hollow out your prim. A cylinder with a hollow of 95 becomes a thin pipe.
• Twist (Begin & End): Twists the prim around its Z-axis. You can set different twist values for the beginning and end of the prim for tapered twisting effects.
• Taper (X & Y): Shrinks or expands the top or bottom of a prim, turning a cube into a pyramid or a cylinder into a cone.
• Path Cut (Begin & End): This is incredibly useful. It slices away a portion of the prim's path. For a cylinder or torus, this can create arcs, semi-circles, and other curved shapes. For a cube, it can create wedges and ramps. Values range from 0.0 to 1.0. For example, setting Path Cut Begin to 0.25 and End to 0.75 on a Torus will give you a perfect semi-circle.

Lesson 3: Practical Application - Building Structures and Objects

Theory is great, but building is a hands-on skill. In this lesson, we combine everything we've learned to create recognizable objects. The key is to look at a real-world object and mentally break it down into the basic prims that form its structure.

Real-World Scenario 1: Building a Simple Chair

A chair is a classic first project. It involves positioning, resizing, and linking.

1. The Seat: Rez a Cube. In the Object tab, set its size to something like X: 0.8, Y: 0.8, Z: 0.1. This is your seat.
2. The Legs: Rez a Cylinder. Size it to X: 0.05, Y: 0.05, Z: 0.5. This is your first leg. Position it under one corner of the seat.
3. Duplicate the Legs: Instead of making three more legs from scratch, select the first leg, hold Shift, and drag it with the move tool. This creates a copy. Do this three more times, positioning one leg under each corner of the seat. Use the camera controls to look from the top and sides to ensure they are aligned.
4. The Backrest: Duplicate the seat prim (Shift+Drag). Change its size to X: 0.8, Y: 0.1, Z: 0.9. Rotate it 90 degrees on the X or Y axis and position it as the chair's back.
5. Linking: Now, select all the prims. Remember to select the main seat prim last so it becomes the root prim (yellow outline). Press Ctrl+L to link everything. You now have a chair!
6. Final Touches: Use the Texture tab to apply a wood texture. In the General tab, give your object a name, like "[Your Name]'s First Chair".

Real-World Scenario 2: Creating a Wall with a Window

This exercise demonstrates the power of the Path Cut and Hollow features.

1. Rez a Cube. Size it to be a wall, for example: X: 4.0, Y: 0.2, Z: 3.0.
2. In the Object tab, set the Hollow value to 95. Your wall now looks like a hollow box frame.
3. Now, we'll use Path Cut to create the window opening. Let's say we want a window in the middle. Set Path Cut Begin to 0.25 and Path Cut End to 0.75. This "cuts away" the top and bottom quarters of the hollow shape's path, leaving an opening.
4. To make a door instead, you could use a prim of the Tube type, cut it, and stretch it vertically. Experimentation is key!

Best Practices for Builders

• Name Everything: In the Edit window's "General" tab, always give your objects a descriptive name and description. This makes finding them in your inventory much easier.
• Understand Permissions: In the General tab, you'll see checkboxes for Next owner: Copy, Modify, Transfer.
  • Modify: Can the next owner edit the object?
  • Copy: Can the next owner make copies of it?
  • Transfer: Can the next owner give it to someone else?
  Be careful with these, especially when giving items to others!
• Save Your Work: Don't forget to take a copy of your finished creation into your inventory! Select the object, go to the File menu, and select "Take Copy." It's good practice to do this often.
• Check Land Impact: While Alife Virtual is generous, be aware that complex prims (those with cuts, hollows, etc.) have a higher "Land Impact" or prim cost than simple cubes. A good builder is an efficient builder. You can see an object's Land Impact in the Edit window.

Hands-On Exercises

Practice makes perfect! Complete these exercises in the school sandbox to solidify your skills. Don't be afraid to ask an instructor for help if you get stuck.

1. The Classic Table:
   Build a rectangular table. It must have a flat top and four legs. The entire object must be linked with the tabletop as the root prim. Apply a texture of your choice.
   Expected Outcome: A single, linked object that looks like a table.
2. The Architectural Archway:
   Using a single Torus prim, use the Path Cut feature to create a perfect semi-circle archway that an avatar can walk through.
   Expected Outcome: A smooth, curved arch made from one prim.
3. The Multi-Textured Crate:
   Create a single cube. Using the Select Face feature, apply a wood texture to the four sides, a different "packing label" texture to the top, and a plain dark color to the bottom.
   Expected Outcome: A single prim with at least two different textures on its faces.
4. The Sculpted Ramp:
   Create a ramp using a single Cube prim. Use the Slice feature (similar to Path Cut) to create a smooth incline.
   Expected Outcome: A wedge-shaped prim that can be used as a ramp.
5. Your Personal Monogram:
   Create your initials using multiple prims (e.g., three prims for the letter 'A'). Position and link them together. Apply a metallic texture and set the Shininess to "High".
   Expected Outcome: A linked object representing your initials with a distinct material look.

Troubleshooting Guide

Every builder runs into problems. Here are solutions to some common frustrations.

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