Model Viewer Technical Guide
Section 4 - VIEWING AND CONTROLLING MODELS IN THE MODEL VIEWER
4.1 Controlling the View
 
4.1.1 Introduction
 

The Model Viewer 3D view window can be moved, resized, minimized, and maximized. When the 3D view window is selected, the images and models can be selected, viewed, and controlled via keyboard commands and mouse movements. For a frame of reference, the 3D view window has a background colour (the default is light blue), and shows the Local Space Rectangular U, V, and W axes as lines. The axis lines meet at the origin (0, 0, 0).

The Model Viewer always faces the origin and cannot turn away from it, but as described later in this section, the current item being viewed can be rotated as desired, and the virtual camera can be zoomed in or out. Models being displayed use the origin indicated by the axis lines as their local origin. If the geometry of a <Model> is not located near the origin of its SRF (and thus, not near the Model Viewer's origin), it may be out of the field of view and only visible by zooming out. By default, the Model Viewer assumes that each root <Model> is constructed close to the origin and is relatively small, leaving it to the user to adjust the zoom and other viewing controls as desired if this is not the case.

4.1.2 Background Colour
 

The background colour can be modified, as shown in the following table.

KEY EFFECT
Q Increase red in the background colour.
W Increase green in the background colour.
E Increase blue in the background colour.
Z Decrease red in the background colour.
X Decrease green in the background colour.
C Decrease blue in the background colour.
4.1.3 Orientation
 

The orientation of the model / image can be controlled for ease of viewing, as shown in the following table.

KEY EFFECT
F9 Increase the rotation about the z axis.
<shift> F9 Decrease the rotation about the z axis.
F10 Increase the inclination.
<shift> F10 Decrease the inclination.
F11 Increase the twist.
<shift> F11 Decrease the twist.
R Reset the view to the original view.
4.1.4 Distance
 

The distance of the virtual "camera" from the model / image can be controlled for ease of viewing, as shown in the following table.

KEY EFFECT
F7 Zoom out, move away from the image / model.
F8 Zoom in, move closer to the image / model.
4.1.5 Display Mode
 

The display mode of the geometry in a model can be controlled by the user, as shown in the following table. The display mode can be set to fill, wireframe, or outline mode.

Fill mode displays geometry with colours and / or textures, that is, filled in.

Wireframe mode displays only the edges of geometry, outlined in the colour of the geometry. For example, for a <Polygon> instance, the boundary lines connecting the vertices would be shown, but the interior of the <Polygon> instance would not be shown.

Outline mode displays the geometry with colours and textures filled in, outlined in black.

KEY EFFECT
A Cycle through display modes: fill, wireframe, and outline.
4.1.6 Texture Blending
 

The rendering of blended textured geometry can be toggled, as shown in the following table.

KEY EFFECT
b Enable / disable rendering of blended textured geometry.
4.1.7 Texture Enabling / Disabling
 

The geometry of models can be shown with or without texture mapping turned on. If texture mapping is turned off, only the colour information, if any, of the geometry is used for rendering.

KEY EFFECT
F12 Enable / disable rendering of textured geometry.
4.1.8 Display List Enabling / Disabling
 

Depending on the hardware and underlying OpenGL implementation available, the user may wish to enable or disable the internal use of OpenGL display lists by Model Viewer. The usage of such lists will be noticeable only under some conditions, depending on whether textures are displayed and whether parts of the model being displayed are moving.

This option is provided in case it will allow the user to speed up rendering on a particular platform.

KEY EFFECT
D Enable / disable use of OpenGL display lists.
4.1.9 Toggle between Image and Model Views
 

The user can toggle between viewing the textures from the <Image Library> instance of the input transmittal, if one is present, and the models from the <Model Library> instance. By default, the textures are displayed in sequence as they are initially loaded by the application, which then automatically puts itself into model viewing mode after all the models are loaded.

If the user invoked Model Viewer initially by turning off either textures or models, then the toggle command will have no effect.

KEY EFFECT
T Toggle between viewing images and models.
4.1.10 Texture Rendering Speed
 

The user can control the quality of texture rendering, as shown in the next table, allowing the user to trade rendering quality for rendering speed.

KEY EFFECT
F Render faster, by using blocker textures on geometry.
S Render slower, using smoother textures on geometry.
4.1.11 Step Through Images / Models
 

The user can step through the images (if the application is in image display mode) or models (if the application is in model display mode), as shown in the following table. (The toggle command for switching between modes is covered earlier in this section.)

Note that this does not display every model in the given <Model Library> instance, but only the models that can be instanced as free-standing objects; that is, the models which have a model_reference_type of either SE_MODREFTYP_ROOT or SE_MODREFTYP_ROOT_AND_COMPONENT.

KEY EFFECT
L Go to next root model.
H Go to previous root model.
J Go to next image or model.
K Go to previous image or model.
4.1.12 Lighting
 

The light source and its characteristics can be controlled as shown in the following table.

KEY EFFECT
F3 Toggle lighting.
M (when supported) Brighten the ambient (infinite) light.
N (when supported) Darken the ambient (infinite) light.
V Toggle spotlight.
G (when supported) Toggle infinite eye-point vs. actual eye-point for lighting calculations. Currently only the default infinite eye-point is supported.
O (when supported) Toggle between inaccurate double-sided lighting vs. accurate double-sided lighting. Currently only the default (2-sided lighting off) is supported.
F4 Toggle shading (flat vs. smooth); the default is flat. Note that this has no visible effect yet, because Model Viewer does not yet support coloured vertices, although OpenGL and SEDRIS both support them.
4.1.13 Print
 

When in model viewing mode, Model Viewer can print out the data structure of the current model and current viewing parameters, as shown in the following table.

KEY EFFECT
P Print out the data structure of the current model and viewing parameters to the text window used to invoke Model Viewer.
4.1.14 Quit
 

To exit the Model Viewer application, press the <escape> key.

4.1.15 Bounding Volume
 

The bounding volume view for models and their individual components can be toggle, as shown in the following table.

KEY EFFECT
E Toggle drawing bounding volumes.
4.1.16 Back Face Culling
 

The back face culling can be toggled, as shown in the following table.

KEY EFFECT
B Toggle back face culling.
4.2 Controlling the Model
 
4.2.1 Moving Articulated Parts
 

Models with articulated parts can be animated, and the animation can be controlled by the user, as shown in the following table.

 
KEY EFFECT
F5 Decrease rotational speed of all parts.
F6 Increase rotational speed of all parts.
4.2.2 State Control
 

Models containing <State Related Geometry> can be controlled by the user, as shown in the following table.

 
KEY EFFECT
I Cycle one value up for the current state of the current model.
U Cycle one value down for the current state of the current model.
Y Cycle through the states that can be changed in the current model.
4.2.3 Level of Detail
 

Models containing <LOD Related Geometry> instances can be controlled by the user, as shown in the following table.

KEY EFFECT
F1 Change to a lower (i.e., closer, more detailed) level of detail.
F2 Change to a higher (i.e., more distant, less detailed) level of detail.
4.3 Summary of Keyboard Commands
 
KEY EFFECT
A Cycle through display modes: fill, wireframe, and outline
B Enable / disable rendering of blended textured geometry
C Decrease blue in the background colour
D Enable / disable use of OpenGL display lists
E Increase blue in the background colour
<esc> Quit the Model Viewer application
F Render faster, in exchange for blockier textures on geometry
G (when supported) Toggle infinite eyepoint vs. actual eyepoint lighting calculations (default is infinite)
H Go to previous root model
I Cycle one value up for the current state of the current model
J Go to next image or model
K Go to previous image or model
L Go to next root model
M (when supported) Brighten the ambient (infinite) light
N (when supported) Darken the ambient (infinite) light
O (when supported) Toggle between inaccurate double-sided lighting vs. accurate double-sided lighting
(default = inaccurate = 2-sided lighting off)
P Print out the data structure of the current model and viewing parameters to the text window.
Q Increase red in the background colour.
R Reset the view to the original view.
S Render slower, but smoother textures on geometry.
T Toggle between images and models.
U Cycle one value down for the current state of the current model.
V (when supported) Toggle spot-light on and off.
W Increase green in the background colour.
X Decrease green in the background colour.
Y Cycle through the kinds of states that can be changed in the current model.
Z Decrease red in the background colour.
F1 Change to a lower (i.e., closer, more detailed) level of detail.
F2 Change to a higher (i.e., more distant, less detailed) level of detail.
F3 Toggle lighting on and off.
F4 Toggle shading (flat vs. smooth, default is flat).
F5 Decrease rotational speed of all parts.
F6 Increase rotational speed of all parts.
F7 Zoom out, move away from the image / model.
F8 Zoom in, move closer to the image / model.
F9 Increase the rotation about the z axis.
<shift> F9 Decrease the rotation about the z axis.
F10 Increase the inclination.
<shift> F10 Decrease the inclination.
F11 Increase the twist.
<shift> F11 Decrease the twist.
F12 Enable / disable rendering of textured geometry.


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