The Viewport¶
The Scene panel is the editor's 3D viewport. It is where you look at the scene, select and arrange entities, add new content, and watch the simulation run when you press Play. You can open several Scene tabs at once, each with its own camera and display settings.
This page covers the panel itself: Scene tabs, the toolbar and its menus, icons, adding content, the right-click menu and what changes during Play. Moving the camera and transforming entities with the mouse and keyboard are covered in Viewport Navigation.
In short
Every Scene tab has a toolbar across its top: transform tools on the left, Play controls in the centre, and the render mode, overlay, collider and camera controls on the right. Most of those controls open a menu from the arrow beside them. Add content from the Create (+) button at the bottom left or by dragging assets in from the Content Browser. Right-click an object for quick actions. Each Scene tab remembers its own settings; Set Scene Default View stores a tab's view in the scene for everyone.
Scene tabs and the active viewport¶
The Scene panel lives in the Main zone, the centre of the editor window. To open another one, click the chevron button at the start of a Main zone tab strip and choose Scene. If the Main zone is empty, click the Add panel button shown there instead. Every new tab is titled Scene.
Each Scene tab has its own camera, toolbar, render mode, and overlay, collider and camera settings. All tabs share the selection, the chosen transform tool, the transform space and the project's denoiser.
- Scene tabs dock only in the Main zone. Drag a tab onto the edge of another tab group to split the zone, for example to put a top view next to a perspective view.
- To give a Scene tab its own window, right-click the tab and choose Move to new window, or drag the tab outside the editor window. Camera controls work there too.
- Close an extra Scene tab with its close button or by middle-clicking the tab. The Scene tab that belongs to the Scene, Server and Observe layouts has no close button.
See Layouts and Docking for tabs, splits and separate windows in general.
The active viewport¶
The Scene tab you clicked into most recently while editing is the active viewport. If it is hidden, for example after you switch layouts, a Scene tab that is showing takes over. Some controls appear only in the active viewport:
- The Play controls and Recorder Status in the centre of the toolbar.
- The Create (+) button and the selection controls at the bottom left, in edit mode.
- During Play, the Force Tool and Free Camera buttons, the high performance mode panel and the scene preparation progress.
When you press Play, the active viewport shows the scene's game camera. Other Scene tabs keep their own editor cameras, so you can watch a running simulation from a second angle. A Scene tab that is hidden behind another tab does not render unless it is the active viewport.
What each Scene tab remembers¶
Each Scene tab remembers its own settings: its render mode and path tracing view, its overlay, collider and gizmo settings, and its transform pivot. For every scene it has shown, it also remembers its camera position, field of view, clip planes, exposure mode and lens settings. The editor saves them a moment after each change, keeps them separately for the Scene tabs of each layout, and restores them the next time you open the project. They are your own settings: they are not stored in the scene or shared with your team.
A Scene tab that has nothing remembered yet, such as a new tab, starts from the scene's default view. So does the camera of a tab showing a scene for the first time. The default view holds a camera position, the Overlay and Colliders settings, the transform pivot and the render mode.
To make the current tab's view the scene's default, open the toolbar's Camera menu and click Set Scene Default View, then save the scene. Anyone who opens the scene without remembered settings, such as a teammate opening it for the first time, gets that view.
Fullscreen¶
The Fullscreen button at the right end of the Main zone's tab strip hides the Left, Right and Bottom zones so the Main zone fills the editor window. Click it again to restore the previous arrangement. Pressing Tab while a Scene tab has keyboard focus (click in it first) does the same. This does not make the editor window itself fullscreen.
The toolbar¶
A toolbar strip runs across the top of every Scene tab. Most of its buttons show only an icon; hover over one to see its name.
| Position | Controls | Shown |
|---|---|---|
| Left | Force Tool and its settings arrow | Active viewport, during Play |
| Left | Select, Translate, Rotate, Scale, Universal; Transform Space and Transform Pivot | Always, except in the active viewport during Play (see below) |
| Centre | Play, or Pause and Stop during Play; Recorder Status | Active viewport |
| Right | Rasterized and Path Traced, and the Path Tracing menu arrow | Always |
| Right | The overlays toggle and the Overlay menu arrow | Always |
| Right | The colliders toggle and the Colliders menu arrow | Always |
| Right | Camera menu | Always, except in the active viewport during Play |
| Right | Free Camera and the Camera menu arrow | Active viewport, during Play |
Several controls are a toggle joined to an arrow: click the icon to turn the feature on or off, and the arrow to open its settings. The menus open below the toolbar and scroll if the window is too short for them. While one toolbar menu is open, moving the pointer onto another toolbar button opens that button's menu instead.
Transform tools¶
| Button | Key | What it does |
|---|---|---|
| Select | Q | Select only, with no gizmo. The default |
| Translate | W | Move gizmo |
| Rotate | E | Rotate gizmo |
| Scale | none | Scale gizmo |
| Universal | T | Move, rotate and uniform scale in one gizmo |
The two buttons after them show the current choice as an icon and open a short menu:
- Transform Space: Global (the default) aligns the gizmo with the world axes, Local with the selected entity's own axes. The tooltip reads Transform Space: Global or Transform Space: Local.
- Transform Pivot: with several entities selected, Median Point (the default) moves, rotates and scales them around one shared pivot. Individual Origins rotates and scales each one around its own origin.
The chosen tool and transform space apply to every Scene tab; the transform pivot belongs to each tab. During Play, the active viewport hides these buttons and its gizmos unless gizmo Visibility in the Overlay menu is Always Show.
Gizmo handles, snapping and keyboard transforms are described in Viewport Navigation.
Play controls¶
Play starts the simulation; F5 does the same from most panels. While the scene plays, Pause (which then reads Resume) and Stop replace it. The arrow button beside them, Recorder Status, opens a popup with the state of the data recorder and its controls, such as Arm Recorder and the bound cameras and lidars; see Recording.
When you are not signed in, the Play tooltip reads "Play (Sign in to LuckyHub to enable recording)". You can still play the scene.
Render mode and path tracing options¶
The joined Rasterized and Path Traced buttons choose how this Scene tab renders. The highlighted one is the mode in use. Each tab has its own render mode, so you can show the two side by side, and you can switch it during Play too. A tab starts in the scene's default render mode: new scenes default to Path Traced where the hardware supports it, and scenes saved by earlier versions to Rasterized.
Path Traced needs a GPU with hardware ray tracing (such as NVIDIA RTX, AMD RX 6000 or later, or Intel Arc) on Windows or Linux. On other GPUs, and on macOS, it is greyed out and the viewport uses Rasterized.
The arrow joined to them (Path tracing options) opens the Path Tracing menu. It is available in Rasterized mode too, so you can set path tracing up in advance.
- View: Lit shows the normal image. The Geometry, Material and Motion Vectors submenus show diagnostic views such as Normals, UVs, Albedo or Surface Motion. The view belongs to this Scene tab, and is greyed out in Rasterized mode.
- Denoiser: None, ReBLUR, ReLAX or NVIDIA DLSS Ray Reconstruction (shown on the button as No Denoiser, ReBLUR, ReLAX or DLSS RR). With ReBLUR or ReLAX selected, the menu adds a Temporal AA toggle. With DLSS Ray Reconstruction selected, it adds a DLSS Mode submenu: Quality, Balanced, Performance, Ultra Performance and DLAA. NVIDIA DLSS Ray Reconstruction needs an NVIDIA RTX GPU; elsewhere it is greyed out and the button shows ReBLUR, which is used instead. The denoiser, Temporal AA and the DLSS mode are project settings: they apply to every Scene tab and are saved with the project.
For what each option does and when to use it, see Rendering and Path Tracing.
Overlays¶
The overlays toggle (Hide Overlays or Show Overlays) hides or shows everything the editor draws over the scene at once: icons, gizmos, the grid, the selection outline, wireframes and bounding boxes, light and camera shapes, spot light coverage, animation bones, lidar points, colliders and the force tool's line. Use it to see the scene as a recording camera would. Each overlay keeps its own setting, so showing overlays again restores them as they were. While overlays are hidden, the colliders toggle and its arrow are greyed out.
The arrow beside it (Overlay options) opens the Overlay menu:
| Section | Setting | Default | Description |
|---|---|---|---|
| Icons | Visibility | Hide in Play Mode | When camera, light and audio icons are drawn: Always Hide, Hide in Play Mode or Always Show. |
| Size | 0.3 | Size of those icons, 0.1 to 5. | |
| Gizmos | Visibility | Hide in Play Mode | When transform gizmos are available: Hide in Play Mode or Always Show. |
| Size | 100% | Size of the transform gizmo, 25% to 400%. Typed values are percentages; 1.5x also works. |
|
| MuJoCo Joints | Off | Edit a MuJoCo joint's pivot and axis with the gizmo instead of moving the entity. Shortcut P. See Viewport Navigation. | |
| Guides | Grid | On | The ground grid. Shortcut Ctrl+G. |
| Selection Wireframe | Off | Draws the selected entities' wireframe over them. | |
| Spotlight Coverage | Off | Outlines the area each shadow-casting spot light in view covers, coloured from blue (a small part of the screen) to red (a large part). | |
| Bounding Boxes | Off | Draws mesh bounding boxes. Shortcut Ctrl+Shift+B. Selected Only (on by default) limits them to the selection; Per Submesh then draws one box per submesh. | |
| Line Width | 2 | Width of the guides, boxes and wireframes, 1 to 10. | |
| Debug | Animation | Off | Draws the bones of animated characters. |
| Lidar View | None | Which lidar points the viewport draws: None, Live Preview, Replay or Auto (Play=Live, Edit=Replay). See Lidar and Lidar Replay. |
Lidar View belongs to the scene, so it applies to every Scene tab at once. The other settings belong to each Scene tab.
Colliders¶
The colliders toggle (Show Colliders (Ctrl+P) or Hide Colliders (Ctrl+P)) shows collision shapes over the scene. Ctrl+P toggles it too, while the viewport has focus or the cursor is over it, except in the active viewport during Play. The arrow beside it opens the Colliders menu:
- Show For: All (the default) draws every collider; Selected and children draws only those of the selection and its children.
- Draw On Top: draws colliders through the meshes in front of them.
- Kinds of Collider: a checkbox for each kind, next to the colour it is drawn in.
| Kind | What it shows |
|---|---|
| Physics (Jolt) | Jolt rigid-body colliders and 2D colliders |
| MuJoCo primitives | MuJoCo box, sphere, capsule, cylinder and plane colliders, and Procedural Mesh primitive colliders |
| MuJoCo mesh (one hull) | MuJoCo mesh colliders without decomposition, drawn as the convex hull of the whole mesh |
| MuJoCo decomposed hulls | The convex hulls a decomposed mesh collider was baked into |
| MuJoCo model geoms | Collision geoms of imported MuJoCo models, such as MJCF robots and scenes |
| Detail regions | Decomposition detail-region boxes, in edit mode |
Viewport camera¶
The Camera button at the right end of the toolbar opens the Camera menu, which sets up this Scene tab's editor camera. It does not change any Camera component. During Play the active viewport shows Free Camera in its place, with the same menu on the arrow beside it (see During Play).
| Setting | Description |
|---|---|
| Vertical FOV | Field of view, 1 to 150 degrees. |
| Near Clip | Closest visible distance, in both render modes. |
| Far Clip | Farthest visible distance. Rasterized mode only, so it is hidden in Path Traced mode. |
| Speed | Base fly speed. The scroll wheel changes it while you fly. |
| Exposure → Mode | Manual, Manual (Physical Camera) or Automatic (Eye Adaptation), each with its own fields below it. |
| Lens | Depth of Field, Sensor Height (mm), Vignetting and Vignette Correction: lens effects that only path tracing renders. With Depth of Field on, Aperture (f-stop), Focus Distance and a Focus Target row with an Orbit Point button appear. Orbit Point sets the focus distance to the camera's orbit point, so press F on an object first to focus on it. |
| Set Scene Default View | Stores this tab's camera position, Overlay and Colliders settings, transform pivot and render mode in the scene, as its default view. Save the scene to keep it. See What each Scene tab remembers. |
Exposure and the lens settings are explained in Cameras and Exposure.
Icons and camera markers¶
Cameras, point, spot and area lights, and audio sources are shown as icons, so you can see and click them:
- Cameras and spot lights are drawn as small 3D models. They turn the accent colour when selected.
- Point lights, area lights and audio sources are drawn as flat icons that turn orange when selected.
Selecting one of them shows its extent:
| Selected | What the viewport draws |
|---|---|
| Camera | A short translucent frustum in the direction the camera looks, starting at its near clip plane, with lines from the camera's position to the frustum's far corners, an arrow marking its up direction, and a small cross at its position. If the camera has a camera binding, the frustum uses the aspect ratio of the binding's resolution. |
| Spot light | A translucent cone matching its Range and Angle. |
| Point light | Three circles at its Radius. |
| Area light | The outline of its shape. |
Icons → Visibility and Size in the Overlay menu control all icons. Hiding the icons also hides the camera frustum and spot light cone. While icons are shown, click one to select its entity.
Each Camera component has a Viewport Icon section in its properties:
- Visible: shows the camera's icon and lets you click it. Turn it off when the icon gets in the way, for example inside a camera housing model. The camera's view and recordings are not affected, and the frustum still appears when the camera is selected.
- Size: scales this camera's icon relative to the icon Size, from 0.05 to 10.
Both settings are saved with the scene.
Camera preview¶
When a camera is selected, a live preview of its view appears in the bottom-right corner of the viewport, with a drop shadow to set it apart from the scene. The preview is a fifth of the viewport's height. Its width follows the camera's aspect ratio: that of the camera's binding resolution if it has a camera binding for recording, otherwise the viewport's. It renders in the Scene tab's render mode. Selecting a Procedural Mesh that contains exactly one camera shows that camera's preview too.
Adding content¶
The Create menu¶
In edit mode the active viewport has a Create (+) button at the bottom left. Its menu opens to the right of the button. New objects appear where the camera is looking, and are selected.
| Item | What it adds |
|---|---|
| Cube, Sphere | A small physics object (scale 0.2) with a MuJoCo mesh collider and a free joint, placed on the surface at the centre of the view if it is within 5 m, otherwise 5 m ahead. |
| Spot Light | A shadow-casting spot light named Light (Intensity 1, Range 15, Angle 45), placed 1.5 m in front of the surface you are looking at if it is within 10 m, otherwise 5 m ahead, and aimed along the view. |
| Camera | A camera at the viewport camera's position and orientation, named Camera (or Camera 1, Camera 2, ...). |
| Robots | Opens the Add robot popup, described below. |
| Script | A new C# script, NewScript.cs, in the project's scripts folder. It opens in the editor and the scripts are built. |
| Assets | Opens the Add asset popup, a searchable online library of 3D models (Search 3D models...). Click a model to download it into the project and add it as a physics object with a MuJoCo mesh collider and a free joint. |
The Add robot popup opens above the bottom of the viewport. It has a Search robots field, a refresh button (Refresh robot catalog) and a card for each robot pack. Click an installed robot (its card reads Add to scene), or drag it into the viewport, to add it to the scene; the popup then closes. A pack that is not installed yet reads Download: click it to install the pack into the project. Press Esc or click outside the popup to close it.
The same robots are listed in the Robots panel (View → Robots), which docks on the right by default and stays open. Click a robot there to add it to the active viewport, or drag it into a Scene tab.
When you add a robot pack that has no policy or script of its own, the editor also creates a starter C# script named after the robot and attaches it. See Robots for working with robots and Creating and Building Scripts for scripts.
Drag and drop from the Content Browser¶
Drag assets from the Content Browser into a Scene tab in edit mode. You can drag several at once. Drops are ignored while the scene is playing.
| Asset | Result |
|---|---|
Mesh, static mesh or Procedural Graph (.hpodgraph) |
Placed where the cursor meets a surface, or on the ground plane if there is nothing under the cursor, and selected. Several of them are laid out in a grid around that point, with rows running across the view. |
| Mesh source file (for example glTF or FBX) | Opens the Create Assets From Mesh Source wizard. Several files each get their own wizard, one after another, titled for example "(2 of 3)". |
| Prefab or MuJoCo scene | Added to the scene and selected. It keeps its own position rather than moving to the drop point. |
| Material | Assigned to the mesh part under the cursor. |
| Scene | Opens that scene, when it is the only asset dragged. |
Robot packs can also be dragged in from the Add robot popup or the Robots panel. See Assets for the Content Browser and Procedural Graphs for Procedural Graphs.
Placing a camera at the current view¶
There are three ways to put a camera exactly where the viewport camera is:
- In the active viewport, click Create (+) and choose Camera.
- In the Scene Hierarchy, right-click empty space and choose Create → Camera → From View. (At World Origin places it at the origin instead.)
- To move an existing entity there, right-click it in the Scene Hierarchy and choose Set Transform to Editor Camera Transform.
Selection controls¶
In edit mode, when exactly one entity is selected, the bottom bar of the active viewport shows quick controls for it, next to the Create (+) button. They step aside while the Create menu is open.
| Control | Shown for | What it does |
|---|---|---|
| Density | Entities with a MuJoCo collider | Collider density, 10 to 1500. |
| Friction | Entities with a MuJoCo collider | Collider friction, 0.1 to 5. |
| Intensity | Lights | The light's intensity. |
| Edit Script (code icon) | Entities with a script | Opens the script in the editor. |
The right-click menu¶
In edit mode, right-click an object in the viewport without dragging. The object is selected and a menu headed with its name opens. Clicking any part of a robot targets the whole robot. The menu is not available while the scene is playing.
| Item | What it does |
|---|---|
| Properties | Brings up the Scene Hierarchy with the entity selected. |
| Duplicate | Duplicates the entity and selects the copy. Greyed out when the entity cannot be duplicated. |
| Delete | Deletes the entity. |
| Edit Script | Opens the entity's script. Shown when the entity has a script. |
| Add Script | Creates a script named after the entity (for example Robot01_Script.cs), builds it, attaches it to the entity, opens it in the editor and shows it in the Content Browser. Shown when the entity has no script. |
| Material | Opens the Material Editor for the entity. Not shown for robots. |
| Add Policy | Lists the project's .honnx policies by name, plus Import Policy.... Shown when the menu targets an imported MuJoCo model, such as a robot. See Robots. |
Right-clicking and dragging flies the camera instead; see Viewport Navigation.
During Play¶
When you press Play, the active viewport shows the scene's main camera (the Camera component with Main Camera ticked). It ignores editor camera, gizmo and selection input, so the simulation runs as it would at runtime.
- Free Camera at the right of the toolbar, or Alt+C, switches the active viewport to the editor camera so you can fly around the running scene. Click it again, or press Alt+C again, to return to the game camera. The arrow beside it opens the Camera menu.
- The overlays and colliders toggles work as they do in edit mode.
- If a script has captured the mouse cursor, press Esc to release it.
Other Scene tabs always use their own editor camera during Play.
The force tool¶
In a scene with MuJoCo enabled, the force tool lets you push and pull bodies with the mouse during Play. Its Force Tool button is at the left of the active viewport's toolbar while the scene plays, in the Scene tab that was active when Play started. Click it to turn the tool on or off.
With the force tool on:
- Left-drag a body to pull it towards the cursor.
- Hold Shift as you start the drag to apply torque instead.
- Right-click during a drag to let go with a push along the line from the camera to the dragged point.
While you drag, a line labelled with the body's name and the applied force, acceleration or torque is drawn. A body that cannot move shows a red message instead, such as "static (worldbody)", "no DOF (welded)", "zero mass" or "welded to a fixed body".
The arrow beside Force Tool (Force tool settings) opens its settings. They are the editor's own settings, shared by every project and remembered between sessions.
| Section | Setting | Description |
|---|---|---|
| Force | Strength | Force per metre between the dragged point and the cursor, in N/m (N/m kg with Relative Force on). |
| Drag Coefficient | Force per unit of difference in velocity between the cursor and the body. | |
| Max | Upper limit on the applied force, in N. | |
| Torque | Rotational Strength | Torque per metre of a Shift-drag, in N·m. |
| Max | Upper limit on the applied torque, in N·m. | |
| Release | Impulse | The push given when you right-click during a drag, in N·s. With Relative Force on it reads Delta v and sets a change in velocity, in m/s. Capped at a 15 m/s change in velocity. |
| Options | Relative Force | Scales force and torque by the body's mass, so every body responds alike. |
| Draw Debug | Draws the line and its label at the dragged point. |
High performance mode¶
When the scene's time mode is Sim High Perf. (Deterministic Uncapped), the active viewport shows a HIGH PERFORMANCE MODE panel during Play, with the current Simulation Speed and these buttons. With the cursor over the viewport, the key in brackets does the same.
| Button | Key | What it does |
|---|---|---|
| Disable Viewport Rendering / Resume Viewport Rendering | V | Stops or resumes drawing the scene, to free the GPU for simulation. |
| Render Single Frame | R | Draws one frame without resuming rendering. |
| Clear Screen | C | Clears the held frame. |
| UI Responsiveness: ON / OFF | U | Keeps the editor responsive during simulation, at a small cost in speed. |
| Switch to Realtime | S | Changes the time mode to Sim Realtime. |
| Open Data Observer | D | Opens the Recorder Status popup. |
| Stop Simulation | Esc | Stops Play. |
See The Time Manager for the time modes.
Status overlays¶
- While the scene prepares to play, the active viewport is dimmed with a progress overlay such as Preparing Scene... or Baking MuJoCo Convex Colliders.... Press Esc to cancel.
- If MuJoCo is enabled for the scene but no MuJoCo model is running, a red Warning: No MuJoCo scene running badge appears at the bottom left during Play.
Where to go next¶
- Viewport Navigation covers flying, orbiting, selecting and transforming entities.
- Rendering explains the two render modes and their settings.
- Layouts and Docking covers arranging Scene tabs and other panels.
- Recording explains the recorder behind Recorder Status.