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Experimenting with Unity 5

Unity 5 has added some really cool lighting and shader features to help artists create more realistic looking scenes. A lot of this is coupled to their out of the box set-up, but it is pretty easy with Unity to write new shaders that take advantage of this new lighting model.

RedFrame has traditionally not made much use of of specular lighting because it required using dynamic lights to add the spec highlights. This slows things down a bit since the scenes have hundreds of thousands of polygons. However it seems like using Unity’s reflection probes is pretty cheap and can help mimic all sorts of real surface types.

As an experiment, I wrote a shader that takes the light map as the diffuse contribution but also has specular and occlusion maps that can interact with box-projected reflection probes. The below video shows the library using this technique on some of the surfaces. There is one dynamic point light in the center of the room to add some more vivid spec highlights, but this is running at a few hundred frames per second with 8x anti-aliasing, so it is a good sign.

Progress Update

For the past five months, Mike and I have been carving out a significant portion of our schedule to work on RedFrame. We’ve made great progress on several fronts. Mike has been working on the main code base, building a robust infrastructure that is now allowing us to set up puzzles and interactions that previously had been held together by ad-hoc prototype code. The types of interactive elements available in the game are very well known at this point so we’ve been able to front-load this engineering work.

During this same time period, I have migrated the entire house to new, cleaner, Maya files, and in the process have greatly improved much of the texturing and quality of models. I’ve also finally been able to get around to working on an area that I had put off for a long time: the yard. Happily I feel that this is now one of the best areas in the game. I’ve also started work on the other environments outside of the house and am planning them out in broad strokes.

All of this work has been aimed toward building our first demo with interactive puzzles which will continue to grow out into the final game. As we begin winding down some of these time consuming programing and art tasks, I will return to puzzle design and Mike will be freed up to work more on environmental storytelling.

There will be a lot to share with you this year and we’re very excited to show it to you. Thanks for the support and stay tuned!

Environment Update

A few months ago I finished building and lighting the the RedFrame house environment. Not including bathrooms, the house has 17 furnished rooms, and a couple outdoor areas. The general look has changed a lot since we last showed a demo. I've started to use higher contrast in many areas, and the general color scheme of each room has converged into a unified style, making each room feel unique. Here's a quick tour of some of the areas that convey the main feel of the game.

-Andrew

Advanced lightmapping in Unity

Note: Lightmapping Extended is no longer compatible with Unity since the Beast light baking system has been removed from the engine.

While investigating potential lightmapping solutions for RedFrame, we explored Unity's own lightmapping system which leverages Autodesk's Beast. Beast unfortunately is lacking a few more obscure features useful for simulating realistic artificial indoor lighting, most notably photometric lights for reconstructing the unique banding patterns indicative of incandescent bulbs installed in housings. This prevents us from completely switching our workflow from Mental Ray to Beast, though we'll likely still use Beast for specific locations in the game that are favorable to Beast's feature set.

Beast is a quite a full-featured lightmapping solution in itself, however Unity's specific implementation of the tool favors simplicity over customization. Some very useful features are hidden away, and it's not immediately obvious how to enable them. To give Beast a fair evaluation, I needed to access them.

Unity fortunately is able to accept Beast XML configuration files, opening up nearly the full potential of the system. There are a plethora of additional options recognized by Beast, but only a limited number are documented by Unity. After a bit of digital archaeology I was able to unearth documents that revealed the missing parts of the API.

I've created a Unity editor tool called Lightmapping Extended  that implements the full Beast XML specification and presents all available (and compatible) options in a user-friendly UI. It's available on GitHub:

Download source code from GitHub

This tool unlocks a few key hidden features not available in Unity's built-in Lightmapping settings window:

  • Image-Based Lighting - light a scene with an HDR skybox, mimicking realistic outdoor lighting
  • Path Tracer GI - a fast, multi-bounce lighting solution
  • Monte Carlo GI - a very slow but extremely accurate lighting solution

Keep an eye on the Lightmapping Extended thread on the Unity forum for future updates. If you run into any issues, please let me know either through the blog comments or the Unity forum thread. I'd like to make this the best and most complete solution for lightmapping inside of Unity.

- Michael

Poly Reduction Prioritization

I recently published a tool for Unity that exposes additional settings for UnitThe central environment in RedFrame is a large mansion. While developing the 3d model of the house I didn't pay much attention to its total resolution; I wanted to see how far I could push mid-range hardware and didn't want the design of the environment to be influenced by technical considerations. To our delight the house runs completely smoothly on an ATI Radeon HD 5770 with a gig of video memory. Although this video card is no slouch, it's also not a high-end gaming GPU.

The resolution of the house model was originally 1,371,298 vertices. We're going to expand the environment quite a bit and will need to keep the game playable on as many systems as possible, so I've started the process of reducing the resolution of the Maya model as much as possible without negatively affecting the way it's perceived by the player. I realized that a lot of our detail was unnecessary; some of the tight detail even detracted from the image by causing flickering when anti-aliasing was disabled.

The scene is quite large, so prioritizing my time is a little difficult. My first thought was just to go through each room looking for objects that are more detailed that they need to be, but this is somewhat arbitrary. My second technique has been to print a list of all objects in the scene and then order them by how much resolution they have. It is still arbitrary in a sense, but it has been a nice weapon with which to attack the problem.

Because I'm more comfortable programing in Unity than in MEL, I wrote a C# script to sort models by resolution. It's my first time using Linq, which I still need to wrap my head around. You can download the script here - just import your model into Unity, drop it into a new scene, and attach the script to the model's root game object.

-Andrew

Lightmap Workflow, Part 1: UV Generation

RedFrame's lighting tends to look a bit different than most games. We achieve this unique look by generating most lighting externally using techniques inspired by pre-rendered architectural visualization. We set up and bake our lighting in Maya and Mental Ray rather than leveraging Unity's built-in lightmap rendering tools.

Our current workflow is a three-step process: generate lightmap UVs, bake direct and/or indirect lighting, and import the resulting lightmap images into Unity's existing lightmap system. In Part 1 in our series on lightmapping we'll explore the process of generating lightmap UVs.

Approach

Unity includes an automatic lightmap UV generation tool. This is a one-way process, and it would be impractical to transfer these UVs back into Maya. Regardless of this limitation, we take a philosophically different approach in our workflow. Where Unity embraces automated simplicity, we've chosen manual control. Our workflow produces two important advantages for us: it creates model files that contain intrinsic lightmap UVs that may be used by other applications and engines, and it offers deep control over how objects are divided at a face level which can produce higher quality results with fewer visual artifacts.

Mesh Grouping

We begin our process of building lightmap UVs by merging environmental geometry into localized groups. The objects in each group will all share the same lightmap texture. Each of these groups are about a quarter the size of a room.

lightmap-uvs-figure1

To optimize the use of texture memory in Unity, we don't want to generate lightmaps for every individual piece of geometry. Separate objects are able to share a single lightmap provided that none of their UVs overlap. To ensure that the objects share a unique UV space, we temporarily merge every object within a group into a single mesh.

Manual UV Layout

Once we have a single mesh for a group of objects, we first must create a new UV set for the mesh. We will want have individual control over the UV layout for both the color and light maps - the second UV set will be used for lightmapping.

In the newly created UV channel, run an automatic UV generation in Maya. This is done by selecting Create UVs -> Automatic Mapping from the polygon menus. The UV map that is generated is usually fairly efficient but it can be compacted further by cutting UV edges that form right angles and then running a Layout operation.

lightmap-uvs-figure2

In this image, the areas circled are spots where it would be a good idea to cut UV edges:

lightmap-uvs-figure3

Manually separating UV shells for smooth objects with hard corners such as crown molding, or softer organic shapes such as upholstered furniture, can also minimize artifacts in lightmaps. Artifacts can be further reduced by tweaking the position of individual vertices as needed.

lightmap-uvs-figure4

Mesh Breakup

Once the mesh containing a group of objects has had its UVs efficiently laid out, we break the mesh into smaller pieces so that they can be culled by Unity via frustum culling and occlusion culling. The most sensible way we've found to re-divide each group mesh is by material. We wrote a MEL script to automatically do this, and we've made it available here.

This script will separate a mesh into pieces based on its materials, and will place each piece into a group node containing all meshes that share the same lightmap UV space. The script is a little ad-hoc and will break if one of the contained materials is the default material. Any suggestions on how we might improve the script are welcome.

Unity Import

Unity uses two UV channels per mesh, the first for displaying color maps and the second for lightmaps. When importing a model, Unity will automatically read the mesh's second UV channel. Be certain to disable "generate lightmap UVs" in the model's asset import settings, otherwise Unity will overwrite the UVs that were manually laid out in Maya.

Check out the next part in our series: Lightmap Workflow, Part 2: Architectural Lighting

Welcome to the RedFrame Development Blog

RedFrame is an exploratory adventure game in production by Andrew Coggeshall and Michael Stevenson. Weve been working on RedFrame in our spare time for more than two years, but until now weve largely kept our work under wraps. Wed like to begin sharing with you what weve accomplished so far, and what still lies ahead as we continue crafting the world of RedFrame.

Through this blog well be highlighting major aspects of development, giving you a peek into our process. This blog will be written from a technical perspective and will be spoiler free. If you have any questions or comments, feel free to contact us.

Thanks, and we hope you enjoy!

Michael & Andrew