Beginning Game Development — Tree Landscape Tool Part III

5 min readSep 2, 2024

Adding Ornaments to the Trees

In the previous articles, we covered how to position trees on the landscape and customize their shapes and colors to create a festive scene. In this third part of our series, we will focus on decorating the trees with ornaments, adding the final touch to your Christmas Tree landscape. Ornaments not only enhance the visual appeal but also bring a joyful and celebratory atmosphere to your scene.

Overview

Decorating your trees with ornaments is a key element in creating a Christmas Tree landscape that feels complete and festive. In this article, we will guide you through the process of placing ornaments on trees, ensuring they are positioned realistically and fit the scale of each tree. We will cover how to manage ornament shapes and colors and how to integrate them into your Unity project using prefabs.

Main Components Covered:
- Ornament Placement: Learn how to position ornaments on your trees correctly, considering tree height, rotation, and avoiding unrealistic placements.
- Ornament Shapes and Colors: Discover how to use simple ornament shapes and colors to add visual interest, and explore variations that can make your scene stand out.

Ornament Placement

Placing ornaments on your trees involves determining where and how they should appear on each tree. Proper placement ensures ornaments look realistic and add to the overall aesthetic without appearing out of place.

Positioning Logic Based on Tree Height and Rotation

When placing ornaments on a tree, consider both the height of the tree and its rotational orientation. For example, if your tree is rotated -90º on the X-axis, the calculations for positioning will need to adjust accordingly.

Ornament Placement Strategy:
- Height Considerations: Avoid placing ornaments too high (near the top) or too low (near the trunk base) by restricting placement within a set vertical range, typically between 10% and 90% of the tree’s height.
- Radial Placement: Ornaments are positioned around the tree using a random angle calculation, ensuring even distribution. This placement uses trigonometric functions (`Mathf.Cos` and `Mathf.Sin`) to calculate positions based on the tree’s radius and height.

Diagram showing the positioning of ornaments on a tree, indicating acceptable placement zones between 10% and 90% of tree height.

Avoiding Unrealistic Placements

To prevent ornaments from appearing in unrealistic positions, such as inside the tree or floating too far from the branches, follow these guidelines:
- Check for Overlap: Ensure ornaments do not overlap with other ornaments or objects within the tree.
- Adjust Radius Based on Height: Reduce the radius as you go higher up the tree to match the natural narrowing of branches.
- Use Randomized but Constrained Angles: Constrain the angles used to position ornaments, keeping them evenly spaced without clustering.

Ornament Shapes and Colors

The shapes and colors of ornaments significantly affect the tree’s appearance. Using simple, single-shape, single-color ornaments provides a classic look, but variations can enhance the festive vibe.

Single-Shape, Single-Color Ornaments

The simplest approach is to use spherical ornaments in a single color, such as red, gold, or silver. This classic look is easy to achieve and maintain within Unity by creating a basic sphere prefab with a metallic or shiny material.

Variations and Enhancements:
- Multiple Colors: Create variations of the same shape in different colors, adding visual interest without complicating the placement process.
- Custom Textures: Add a texture to your ornaments to give them more detail, like a glittery or patterned surface.

Integration of `TreeOrnament` Prefabs

Using a `TreeOrnament` prefab allows you to group multiple ornaments together, ensuring consistent scale and positioning relative to the tree. This prefab can be adjusted and reused across different trees, saving time and maintaining a uniform look.

Benefits of Using Prefabs:
- Scalability: Easily adjust and scale the entire set of ornaments to fit any tree.
- Consistency: Maintain consistent ornament styles across multiple trees.
- Flexibility: Quickly make changes to ornament placement or styles by modifying the prefab.

Implementation

Below is a step-by-step guide for creating and positioning ornaments on your trees using Unity’s prefab system.

Step 1: Creating an Ornament Prefab

1. Create a Sphere Object: In Unity, create a sphere to serve as your ornament. Adjust the size to match the desired look.
2. Apply a Material: Add a material to the sphere that matches your chosen color and style (e.g., metallic red or glossy gold).
3. Save as Prefab: Drag the sphere into the project window to save it as a prefab named `OrnamentPrefab`.

Screenshot of Unity Editor showing the creation of an ornament prefab with applied materials in the inspector.

Step 2: Positioning Ornaments on Trees

The following script demonstrates how to position ornaments on trees based on height, rotation, and acceptable placement zones:

using UnityEngine;
using UnityEngine.Networking;

public class Server : NetworkManager
{
    public override void OnServerConnect(NetworkConnection conn)
    {

Screenshot of Unity Editor showing ornaments correctly placed on a tree, following the constraints outlined in the code.

Step 3: Managing Ornament Scaling and Hierarchy

To ensure ornaments are consistently scaled and managed within the tree hierarchy:
- Set Ornaments as Children of Trees: Parent all ornament instances to the tree, ensuring they move and scale with the tree.
- Maintain Scale Consistency: Do not scale ornaments separately; ensure their prefab is already scaled appropriately to match the tree.

Diagram showing the hierarchy setup in Unity, with ornaments correctly parented under the tree object.

Conclusion and Next Steps

Adding ornaments to your Christmas trees adds the perfect festive touch to your landscape. By carefully positioning ornaments and managing their scale, you ensure they enhance the scene without disrupting the overall design. In the final part of this series, we will explore how to export your completed Christmas Tree landscape, making it ready for gameplay or sharing.