Migrating to UNIGINE from Unity: Content Creation

In Unity software, you are likely to be used to using the LOD Group component enabling you to operate several detail levels, the active LOD is defined by the threshold based on the ratio of the mesh's screen-space height to the total screen height.

In UNIGINE, levels of detail are configured based on distances — in a more low-level manner to make fine tuning available. Surfaces have visibility settings for this purpose. You can set the minimum and maximum visibility distances from the camera for each surface. For Cross Fading use the Minimum and Maximum Fade values.

Automatic creation of LODs upon importing a model is described in the FBX Import Guide. For more details on configuring LODs refer to the dedicated article.

FBX models containing bone-animated skinned meshes create animation clips when imported in both engines. In UNIGINE, such clips are represented by .anim assets.

Skinned Mesh object is an analog for Unity Skinned Mesh Renderer component for handling bone animations.

Unity software provides a sophisticated animation system (sometimes referred to as 'Mecanim'). It implies using Animator Controller — a state machine that manages animation states and transitions between them.

The UNIGINE's skinned animation system is focused on operating animation layers: you can configure multiple layers with various animation clips and perform blending between them by using API methods.

For more details refer to the following articles:

• ObjectMeshSkinned class API reference.
• Animation section of C# Component Samples.

Blend Shapes#

In Unity software, light sources are represented by the Light component. UNIGINE provides several types of light sources similar to the ones of Unity software.

Shadows#

Lights Cookies#

For texture modulated lights Unity software has a special type of textures: Cookie.

In UNIGINE, you can use an arbitrary flat diffuse or albedo texture in the Texture parameter of a Projected Light. The same way you can apply texture modulation to an Omni Light by using a cubemap texture.

Modulation by texture

Modulation by cubemap

In Unity Editor, scene environment settings are placed in the Lighting window (menu: Window > Rendering > Lighting Settings). The Environment section contains settings for the skybox, diffuse lighting and environment reflections.

In UNIGINE, similar Environment Settings are available in the Render Settings (choose Window -> Settings in the main menu, then in the Settings window go to Runtime -> World -> Render -> Environment).

UNIGINE provides three environment presets, by configuring which you can create a smooth transition between different weather conditions.

In order to achieve physically correct atmosphere rendering, UNIGINE's environment system simulates Scattering by interpolating certain LUTs (Look-UP Textures). When configuring environment lighting you should consider all the settings combined. For more details visit the dedicated article.

You can set a cubemap texture as the Environment Texture (a Unity Skybox counterpart) for both sky color and reflections.

Additionally, Unity Editor allows to specify a different environment skybox for the camera by using the Skybox script.

In UNIGINE, you can use a Sky Object recreating the atmosphere in the scene. It can represent a hemisphere or a full sphere with a cubemap assigned, tiled with clouds texture to produce plausible and inexpensive dynamic clouds.

Fog#

Unity software provides a set of advanced systems that model indirect lighting significantly improving the realistic look of the scene. So does UNIGINE. This section lists Unity GI techniques and ways to get the same or similar results in UNIGINE.

Lightmaps#

Light Probes#

Reflection Probes#

Baked Ambient Occlusion#

In Unity software, Audio Source components play back Audio Clips. There must be an Audio Listener component, usually attached to the main camera by default, to make the sounds audible. The Spatial Blend parameter of the Audio Source component allows controlling the blending between 2D and 3D spatial sound.

In UNIGINE, Sounde Source node type is responsible for playing back an audio asset. It provides a surround effect the same way as it does Unity software. There is no such entity as the Unity Audio Listener — all sound sources that appear in the world are audible. While many parameters seem rather familiar to you, such settings as Doppler level, Attenuation (Rolloff) function and other, including Audio Mixer channels, are available only globally in the Sound section of the Settings window.

UNIGINE supports HRTF (Head Related Transfer Function) out of the box, so imitation of surround sound for stereo headsets is close to real life.

Another sound source entity in UNIGINE is the Ambient Source used to create a non-directional ambient background sound (e.g. background music). It has no position in the world and, therefore, can't be represented as a node. So it is available only via API.

Just like Reverb Zones in Unity software, UNIGINE's Sound Reverb objects represent reverberation zones where ambient sound effect appears provided the player is within the zone. With fine-tuned parameters a reverberation zone correctly reproduces the way the sound is reflected from surfaces, forming three main components:

• Early reflections
• Late reverberation
• Echo

Besides that, a number of parameters can be changed to alter the type of environment being simulated. A number of presets may help you to quickly choose the most suitable type of environment to simulate:

By adjusting the Threshold parameter you can enable smooth sound transition when the listener moves from the outside area into the reverberation zone.

Unity software provides an advanced Video Player component capable of rendering videoclips of various formats to textures and other targets.

In UNIGINE, video playback is supported only in a virtual monitor as a part of GUI system. Currently only *.OGV files are supported.

Unity software provides mipmap-based Texture Streaming. This system reduces the total amount of memory Unity software needs for textures by loading only the mipmaps that are needed to render the current camera position in the scene.

The Texture Streaming settings are provided in Unity Quality Settings.

In UNIGINE, textures streaming is a part of the advanced Asynchronous Data Streaming system. This system is intended to reduce spikes caused by loading of graphic resources, such as meshes and textures. Only the resources that are required to render the current camera view are loaded; and unloaded as soon as other resources require to be loaded to video memory in order not to exceed the specified memory limits. Uploading is time-sliced so as to avoid spikes when the world is just loaded.

Settings for fine adjustment are available in the Streaming section of the Settings window:

Asynchronous Texture Upload#

In Unity Editor you can bake static GameObjects with the Static Occluder flag enabled into View Volumes for Occlusion Culling to define the geometry that will block the GameObjects with the Static Occludee enabled from rendering. This technique extremely reduces the number of polygons rendered.

Also, it is normal for you, as a Unity user, to define View Volumes using Occlusion Areas and use Occlusion Portals to represent GameObjects that can be both open and closed in terms of blocking the sight, such as doors.

In UNIGINE, Occlusion Culling technique is represented by two methods:

• Occluders. Use box-shaped and mesh-based objects culling geometry occluded by them.

  

• Hardware Occlusion Queries technique allows skipping rendering of objects, the bounding boxes of which are covered by another opaque geometry.

  

Draw call batching in Unity software is a way to reduce the number of draw calls by combining static GameObjects sharing the same material into big meshes. In order to take advantage of static batching, one needs to enable the Batching Static flag of a GameObject:

As well as Unity software, UNIGINE performs Draw call batching: all opaque surfaces are automatically grouped and rendered in batches according to materials assigned, thus decreasing the number of DIP calls and, therefore, increasing the performance. This is why sometimes it is reasonable to create Texture Atlases, so even objects using different textures could share the same material in order to be subject to batching.

UNIGINE provides additional objects to take full advantage of mesh batching:

• Mesh Clutter is an object used to scatter a large number of identical meshes across the world. It is suitable for simulating vegetation a lot while keeping performance high.

  

• Mesh Cluster is an object that can contain a great number of identical meshes with the same material, which are managed as one object. Cluster meshes can be scattered either automatically, or each mesh can be positioned, rotated, and scaled manually.

  

Follow the Working with Large Number of Objects article for more details on using these objects.

In Unity software, you use Billboard Asset — a collection of pre-rendered images of a more complicated Mesh intended for use with the Billboard Renderer component — to replace the complex 3D mesh with a 2D billboard representation at some distance from the camera, thus reducing the load on GPU.

The most common way to generate a Billboard Asset is to use a third-party software or create Billboard Assets from script.

UNIGINE provides support for Billboards as well. In UNIGINE, a billboard is a rectangular flat object that always faces the camera so it is capable of representing some flat effects and objects that are barely seen from far off.

You can generate a billboard-based impostor using the Impostors Creator. This out-of-the-box tool creates a series of snapshots of the object while saving shading fidelity and combines them in a single Billboard object. Now you can use the impostor object as the lowest LOD for the mesh at a distance.

Impostor albedo texture	Object and Impostor wireframes

In Unity Editor you are accustomed to assign Tags to GameObjects for user-defined classification of them. You also use Layers to define groups of GameObjects to be unapproachable by light sources and cameras, as well as for selective raycasting and collisions.

In UNIGINE, a high level of abstraction is omitted, both these systems are represented by the Bit Masking mechanism. Objects, cameras, materials and other entities have bit masks used by various effects and features to define their scope. Each bit in a bit mask can be named for convenience.

The masks are compared bitwise using logical conjunction, so if two masks have at least one matching bit enabled, they match and, therefore, the entity is subject to the effect.

For instance, you can filter out certain objects (e.g. tooltips) for reflections by adjusting the Reflection Viewport Masks:

For more details and usage examples:

• Proceed to the Bit Masking article
• Watch the dedicated video tutorial.

All runtime spikes, bottlenecks and performance issues can be tracked using the built-in optimization tools:

• Performance Profiler, an analog for Unity Profiler tool, displays performance data in a timeline in several modes.
  
  

  

• Microprofile, an advanced CPU/GPU profiler with support for per-frame inspection.
  
  

  

• Texture Profiler, a tool helping to check the memory consumption by textures.
  
  

  

See Also#