Cameras and View Control

Without a camera, a scene shows nothing. This page covers the default camera, perspective/orthographic, aiming at targets, CameraController interaction, and multi-camera plus render-to-texture.

Shortest runnable path: place the camera and see the scene

Every scene ships with a default camera, Scene.MainCamera (the control's view.MainCamera is exactly that) — no need to create one:

private void OnSceneInitialized(object sender, InitializedRoutedEventArgs args)
{
    var view = (Aura3DView)sender;

    var camera = view.MainCamera;
    camera.Position = new Vector3(0, 5, 10);
    camera.LookAt(new Vector3(0, 0, 0));   // aim at the world origin
}

For mouse/keyboard interaction, add a controller (see the CameraController section below).

Projection type and parameters

ProjectionType switches between perspective and orthographic; each has its own parameters:

var camera = view.MainCamera;

// Perspective (default)
camera.ProjectionType = ProjectionType.Perspective;
camera.FieldOfView = 60f;      // field of view in degrees
camera.NearPlane = 0.1f;       // near clip plane
camera.FarPlane = 1000f;       // far clip plane

// Orthographic (no perspective falloff; good for 2D views and top-down editors)
camera.ProjectionType = ProjectionType.Orthographic;
camera.OrthographicSize = 10f; // orthographic view size

Parameter	Type	Default	Projection	Description
ProjectionType	Perspective / Orthographic	Perspective	—	Projection mode
FieldOfView	float	75	Perspective	Vertical field of view (degrees)
NearPlane	float	1	Both	Near clip plane
FarPlane	float	100	Both	Far clip plane — anything beyond is not rendered
OrthographicSize	float	5	Orthographic	Orthographic view size
IsRenderBackground	bool	true	—	Whether this camera renders the background/skybox

IMPORTANT

Projection parameters are validated at assignment time: NearPlane > 0, FarPlane > NearPlane, FieldOfView within (0, 180) degrees, OrthographicSize > 0, and every value must be finite — violating any rule raises an error immediately. So when both clip planes must change substantially together (e.g. from Near=1, Far=100 to Near=200, Far=400), assigning them one by one passes through an invalid intermediate state where Far < Near. Use the atomic update instead:

camera.SetClippingPlanes(200f, 400f);

Aiming at targets and auto-framing

When you don't want to compute rotation angles by hand, use these two methods instead of setting RotationDegrees:

// Look at a world-space point
camera.LookAt(new Vector3(0, 1f, 0));

// Move and orient automatically so the bounding box fits the view (padding = margin ratio)
camera.FitToBoundingBox(model.BoundingBox, padding: 0.5f);

FitToBoundingBox pairs with a model's BoundingBox and is the standard way to "see the model I just loaded" immediately.

The camera's own pose still uses the regular node properties (Position, RotationDegrees) — see The Scene Graph and Nodes. Custom shaders can read the camera matrices through the read-only properties:

Matrix4x4 viewMatrix = camera.View;
Matrix4x4 projMatrix = camera.Projection;
Matrix4x4 vpMatrix = camera.ViewProjection;

Mouse and keyboard control: CameraController

CameraController subscribes to the control's input and drives MainCamera. Default bindings:

• WASD / QE: move forward/back/left/right/up/down
• Right-drag: rotate the view
• Scroll wheel: zoom
• Middle-drag: pan

private CameraController _cameraController;

public void OnSceneInitialized(object sender, InitializedRoutedEventArgs args)
{
    var view = (Aura3DView)sender;

    _cameraController = new CameraController(view)
    {
        MoveSpeed = 30f,          // movement speed
        MouseSensitivity = 20f,   // mouse sensitivity
        ZoomSpeed = 5f,           // zoom speed
    };
}

Configurable properties:

Property	Type	Default	Description
MoveSpeed	float	10f	Keyboard movement speed
MouseSensitivity	float	20f	Mouse look sensitivity
PanSpeed	float	10f	Pan speed
ZoomSpeed	float	5f	Zoom speed
Enabled	bool	true	Master on/off
EnableLook	bool	true	Rotation (right-drag)
EnableMovement	bool	true	WASD/QE movement
EnableZoom	bool	true	Scroll zoom
EnablePan	bool	true	Middle-click pan

NOTE

CameraController implements IDisposable. It hooks the control's input events, so call Dispose() when you no longer need it (page unload, mode switches).

Multi-camera and split views

All Camera nodes in the scene are automatically discovered by the render pipeline and rendered one by one: every pass registered in RenderPassGroup.EveryCamera runs once per camera. Adding a second camera is just a normal node:

var secondCamera = new Camera
{
    Position = new Vector3(10, 5, 0),
    IsRenderBackground = false,  // key: don't render the skybox twice
};
secondCamera.LookAt(Vector3.Zero);

scene.AddNode(secondCamera);

TIP

Only one camera should own the background (default IsRenderBackground = true). Turn the property off for the rest, or the skybox gets drawn multiple times — wasteful and prone to overwriting each other.

Render to texture: minimaps and monitor views

Assigning a RenderTarget to a camera sends its image into a texture instead of the main screen — typical uses are minimaps, rear-view mirrors and surveillance monitors:

// Create an off-screen render target
var renderTarget = new ControlRenderTarget(width, height);
secondCamera.RenderTarget = renderTarget;

// After rendering, read the texture in SceneUpdated and feed it as a material input —
// e.g. map it onto a PlaneGeometry and you have a minimap inside the scene

Pipeline-level details — CameraOutput, render target registration, multi-pass orchestration — are in Choosing and Configuring Pipelines.

Common pitfalls

• The scene is completely empty: first check that a camera exists and is aimed at the subject — if the model isn't in view, use LookAt or FitToBoundingBox to frame it, then check for a light source (see Lighting and Shadows).
• Distant ground/models get clipped: FarPlane defaults to just 100; raise it for large scenes (e.g. camera.FarPlane = 250f). Conversely, pushing clip planes too far apart hurts depth precision and worsens z-fighting.
• Assigning clip planes throws: setting them individually passes through an invalid intermediate state (Far <= Near). When both change, use SetClippingPlanes(near, far) — see the validation note above.
• The second camera draws the skybox again: set IsRenderBackground = false on it.
• Keyboard/mouse still control the old scene after navigating away: the CameraController was never disposed and its handlers are still attached to the control.

Runnable examples

• Camera demo — perspective/orthographic switching, FOV and clip-plane sliders, LookAt, FitToBoundingBox, and world-to-screen readout verification.

Next steps

• Choosing and Configuring Pipelines — how multi-camera rendering works at the pipeline level and what CameraOutput is.
• Environment and Background — give the IsRenderBackground = true camera a skybox.