XAML 3D Viewport Element

Modified on 2018/08/03 01:54 by Administrator — Categorized as: 3D Graphics, Base Elements, Elements

Summary

Element Icon XAML 3D Viewport
Info
Category: 3D Graphics AddIn: Base Layer
Creator: OkazoLab Scope: Parent event
Owns Snippets: None Usage: Stimulus screen

Properties

NameDescription                              ConstraintsTypeOn
runtime
change
Camera Orbit
Orbit Rotation        Defines an orbital rotation of the camera on the current 3D scene. The vector fields X,Y and Z represent Yew, Pitch and Roll values in degrees.        
Normal..
        		Vector..         
Orbit Center        Defines the center point of the camera orbit in the world coordinates.        
Normal..
        		Point3D         
Orbit Scale        Defines a scale of the camera orbit relative to the orbit center. The value is in percentages, such that 100% matches to the camera position defined in the current 3D scene.        
Normal..
        		Double         
Camera Settings
Camera Position        Defines a camera location in the world coordinates. The property does not specify the camera direction vector. The direction is defined by the Camera Lookup Direction property.        
Normal..
        		Point3D         
Lookup Direction        Defines the camera lookup vector- a direction in which the camera is looking in world coordinates.        
Normal..
        		Vector..         
Camera Up Direction        Defines a unit vector that represents the upward direction of the camera (and 3D model projection)        
Normal..
        		Vector..         
Near Plane Distance        Defines a distance from the camera to the camera's near clip plane        
Normal..
        		Double         
Far Plane Distance        Defines a distance from the camera to the camera's far clip plane        
Normal..
        		Double         
Field of view        Defines horizontal bounds of the camera's projection, as degrees between the camera's position and the image plane        
Normal..
        		Double         
Object Tracking
Is Tracking        Enables tracking and selection of 3D objects with a 2D positional device, e.g. mouse or eye-tracker. The tracking returns a name of the closest object pointed on the current projection of 3D model        
Design Time..
        		Boolean         
Tracked Object        Returns a name of the pointed 3D object among all objects on a 3D scene. The object name has to be defined in the XAML 3D model. When no object is pointed, the property returns an empty string.        
Normal..
        		String         
Tracked Point        Returns 3D coordinates of the focal dot on the pointed 3D object. When no object is pointed, the property returns the zero point.        
Normal..
        		Point3D         
Tracking Distance        Returns a distance from the camera to the focal dot of the tracked 3D object (in the world units). When no object is pointed, the property returns the zero.        
Normal..
        		Double         
Material List
Selected Index        Defines an index of the selected library item in the list of this element        
Normal..
        		Int32         
Selected Item        Defines a name if the selected library item in the list of this element        
Normal..
        		String         
Item Count        Return the total number of material items in the list of this element        
Status..
        		Int32         
Visual Appearance
Alpha Masking        Defines, whether the visual content is used to create an opacity mask on the event surface. If masking is on, the content's pixel luminance (or, its inverse) defines transparency within element's viewport. The alpha masking allows, for example, create transparent holes on the event surface.        
Design Time..
        		Int32         
AntiAliasing        if true, the rendered content will be antialiased for smoother visual appeariance. If false, rendering will be authentic to its source, e.g. a bitmap.        
Normal..
        		Boolean         
Position        Defines a position of the rendering viewport on the screen        
Normal..
        		clPoint         
Size        Defines a size of the element's rendering viewport on the screen        
Normal..
        		clSize         
Z Order        Indicates Z Order of the element on the given event        
Status..
        		Int32         
Pivot Point        Defines alignment of the pivot point (or, element's position) relative to element's rendering area. The pivot point sets the center of element's rotation and scale directions.        
Normal..
        		stAlig..         
Visible        Defines whether the element is visible        
Normal..
        		Boolean         
Rotation        Rotation angle in degrees        
Normal..
        		Double         
Effects
Transparent Color        The color of the original pixels of rendered content that will be set as transparent        
Normal..
        		stColor         
Transparent Tolerance        Tolerance ratio for choosing colors that become transparent. Zero means that effect is not applied, 1 denotes that all colors will become trasparent        
Normal..
        		Int32         
Color Mask        Produces a multiplicative combination of the original pixels and the selected mask color (except the alpha channel).  The effect emulates a look through a colored glass.  White or transparent mask color dont change the original pixels        
Normal..
        		stColor         
Opacity        Opacity of the rendered content        
Normal..
        		Int32         
Contrast        Contrast of the rendered content        
Normal..
        		Int32         
Brightness        Brightness the rendered content        
Normal..
        		Int32         
Saturation        Saturation of the rendered content        
Normal..
        		Double         
Pixelation        Pixelation of the rendered content        
Normal..
        		Int32         
Blurring        The radius used in the gaussian blur of rendered content, as a pixel-based factor. The default is 0 which means no blurring.        
Normal..
        		Int32         
Scrambling                
Normal..
        		Double         
Scrambling Grid Size        Defines a size of the scrambling grid        
Normal..
        		clSize         
Positional Jitter
Reset Jitter Now        Runtime command that resets the positional jitter.        
Runtime Command..
        		Boolean         
Current Jitter        Returns the current jitter        
Status..
        		clPoint         
Jitter Range        Defines a possible range for the random jitter. The range is centered to the position of the element.        
Normal..
        		clSize         
Control
Is Enabled        If set to false the element is completely omitted when the experiment is run        
Design Time..
        		Boolean         
Title        Title of the element        
Design Time..
        		String         

XAML 3D Viewport Element renders a dynamic viewport projection of 3D models stored in the XAML 3D format. XAML 3D is a subpart of the XAML language intended for description of simple and complex 3D models. In contrast to other 3D formats, XAML 3D allows dynamic adjustments of model's parameters (e.g. object positions, materials, lighting) via data binding. If you want to use static 3D models with a camera control, you may prefer the 3D Viewport element, because it supports many 3D formats, e.g. the Wavefront obj. The XAML 3D viewport element is the best choice for creating 3D animations, interactive 3D scenes and the hit testing scenarios. Multiple 3D models can be loaded into element's material list to form a 3D stimulus set.


Description

XAML 3D is a sub-branch of the XAML markup language intended for description of 3D models of any level of complexity. In contrast to other 3D formats, XAML 3D allows dynamic adjustments of all 3D model's parameters (e.g. object positions, materials, lighting) via scripting or XAML data binding. (Note that if you want to use static 3D models with a camera control, you may prefer the 3D Viewport element in EventIDE, because the latter supports more common 3D formats, e.g. the Wavefront obj). The XAML 3D viewport element is the best choice for creating 3D animations, interactive 3D scenes and the hittest-based object tracking. Multiple 3D models can be loaded into element's material list to form a switchable 3D stimulus set.

Preparing 3D models

Before you deploy the XAML 3D Viewport element, you have to create or import XAML 3D models into Material Library.

Picking up a XAML 3D template

EventIDE provides the XAML template gallery, which includes a number of basic 3D models. Once you select a 3D model in the gallery, it will be added into Material Library. Before adding a model, you can choose its material color. You can find the 3D models in the last row of the template gallery (Library ribbon tab->Add XAML template):

Basic 3D models
Basic 3D models in the template gallery

Importing the XAML 3D files

XAML 3D models are stored in a special file format supported in several 3D editors:


You can import existing XAML 3D files into Material Library using the 'Load Materials' command (or, simply dropping the XAML files into the Library panel). If a 3D model has references to external material files, the materials will also be automatically imported.

ImageImageImage
Examples of the XAML 3D models rendered in an interactive preview panel. Complete model's statistics is shown in the superimposed text blocks.

Editing 3D models

A XAML 3D model is defined by a markup script, which can be previewed and edited in EventIDE. The script is made of a hierarchy of description tags for camera, lighting, materials, transforms and object meshes. You can see a content of the markup script for a cube model on the next screenshot.

Image
Editor for XAML 3D script (click to enlarge).
Note the highlighted line that show the data binding syntax.
The data binding makes the material color linked to a user variable that can be changed at runtime.

Deploying the 3D XAML Viewport element

Creating a single 3D stimulus

  1. Select an event, which will contain a 3D stimulus
  2. Add a new 3D XAML Vieweport element and select it in the Elements panel
  3. Open Material Library and start dragging a selected 3D model
  4. Drop the model over the 3D XAML Vieweport icon in the Elements panel
  5. If required, adjust the position and size of the 3D XAML Vieweport on the event surface
  6. If required, modify other element's properties (e.g. the camera orbit position) in the Properties panel

Creating a switchable 3D stimulus set

  1. Repeat the above steps, except that this time you drag multiple 3D models into the 3D XAML Vieweport element.
  2. If required, switch the models by the 'Selected Index' or 'Selected Item' properties of the 3D XAML Vieweport element.

Controlling camera settings

Beside XAML data binding, the 3D XAML Viewport element enables direct control of camera settings via the element's properties. These properties include the camera position, look-up direction, up direction, near and far plane distance and field of view. Once a new 3D model is selected in the element's material list, these properties receive the initial values defined in the XAML 3D script. If you change the values, the viewport projection is automatically updated.

Animating the camera orbit position

3D animation is often generated by moving a camera over a 3D model. However, beside setting a new camera position on each animation step, you have to also recalculate the camera directions settings relative to the 3D model. The 3D XAML Viewport element offers much easier way to generate 3D animation with the camera orbit rotation. In this type of motion, the camera 'focus' point is fixed at the selected point (usually the coordinate origin) on a 3D model. The camera distance to the focus point is also fixed. To produce animation, you just change the Yaw, Pitch and Roll angles defining the orbital position of camera. The camera orbit angles are represented by the 'Orbit Rotation' property of the 3D XAML Viewport element. The property has a Vector3D data type, in which X,Y and Z fields represent the Yaw, Pitch and Roll angles respectively. For instance, to produce the 'Earth' rotation over a model you can use just one code line: 

OrbitRotation.X=OrbitRotation.X+2.5;

When necessary, the camera 'focus' point and distance can be adjusted with 'Orbit Center' and 'Orbit Scale' properties of the 3D XAML Viewport element.

Dynamic object tracking

The 3D XAML Viewport element allows dynamic object tracking with 2D positional input over a projection viewport. Imagine a participant moving a mouse over a viewport. The 3D XAML Viewport element reads the mouse posotion and build a 3D ray orthogonal to the projection (or, camera) plain. If the ray touches any 3D object in the model, the element returns a name of this tracked object, 3D coordinates of touched point on the object surface and the camera-object distance. If the ray penetrates through several objects in the model, the closest object to the camera plane is selected. See the following example of object tracking on a animated 3D scene recorded in EventIDE: Other positional devices, such as eye-trackers, joysticks, etc can also used for the 3D object tracking.

Notes