Viewing Commands

Basic Functions > Viewing a Model > 7.3 Viewing Commands

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7.3 Viewing Commands

The following is a detailed description of the commands and dialog boxes that manage and manipulate views.


Viewing>Transformations	Transforming Views

With the icons of the View>Transformations dialog box you can pan, rotate, zoom, or fit the view in the current viewport. Transformations are incremental, each mouse click will modify the view orientation once by a predefined amount that you specify in the Options... dialog box.


	Visually translates (pans) the model in the view left, right, up, or down, by a selected incremental “pan factor”.
	Visually rotates the model in the view around the X, Y, or Z axis clockwise or counterclockwise by a selected incremental rotational angle.
	Visually increases or decreases the size of the model in the view by a selected zoom factor.
	Fits the view of the model inside the viewport boundaries.

Transformation Options

If you pressed the Options... button in the View>Transformations dialog box, you will see the subordinate dialog box shown below.


Rotation	Displays the rotation angle in degrees. Each mouse click will rotate the view of the model by that increment. Move the slidebar to the desired angle value.
Model Relative	The rotation takes place about global axes.
Screen Relative	The rotation takes place about screen axes.
Pan Factor	Displays the panning rate in model units. Each mouse click will move the view of the model by that increment. Move the slidebar to the desired panning rate value.
Zoom Factor	Displays the zooming rate. Each mouse click will zoom the view of the model at that rate. Move the slidebar to the desired zoom factor value.

Fit View

Fitting a view moves and resizes the view of the model so that all model entities will fit inside the current viewport window. The view’s rotational orientation will remain the same (for automatic execution of Fit View, see Automatic View Settings, 458).

Select Center

The Viewing>Select Center command is an alternative way of panning the model. Click an arbitrary point in the viewport and the view will be repositioned with its window center at the selected point. Note that if you picked a point in a viewport other than the current one, that viewport will automatically become the current viewport.

Select Corners

Using the Viewing>Select Corner command, you can zoom to a cursor-defined rectangular area of the current view of the model.

Move the cursor to a point at the edge of the area you wish to zoom (P1). This point becomes the first corner of the rectangle. Click and hold down the left mouse button while dragging it to form the rectangle. When the rectangle surrounds the desired area, release the mouse button at the opposite corner (P2). The view’s center will reposition itself to the center of the rectangle, and the selected area will zoom to fill the viewport.

The viewport in which you select the corners will automatically become the current viewport.


Viewing>Zoom (% of View)	Zoom by a Specified Factor

The Viewing>Zoom (% of View) command lets you specify the zoom rate numerically rather than using the zoom icon and the slidebar.


Zoom Factor	The zoom factor is expressed as a percentage of the fit view size.
Custom...	Enter a zoom factor in this subordinate dialog box if you want to use a zoom factor other than those listed.


Viewing>Angles	Rotate by a Specified Angle

Use the Viewing>Angles command when you want to enter very specific rotation angles that are not easily set with the rotation slidebar, or when you want to control the axes about which the view is rotated.

Rotation Terminology


Model	The view is rotated about the global model axes. These stay fixed to the model and rotate with the model.
Screen	The view is rotated about the screen axes. These are fixed to the screen and never move.
Absolute	The view is rotated relative to the zero (unrotated) position.
Relative	The view is rotated relative to the current view position.
Rotation Angles	The angle of rotation may be positive or negative around the respective axis (follow the right hand rule).
Unit of Rotation	The unit of rotation is degree, the allowable range is ±180o.
Center of View Rotation	The center of rotation is the focal point (see Observation Point, 356); the only point that remains fixed during a view rotation. If the center of rotation does not coincide with the model center, the center of the model will move, and a portion of the model (or the entire model) will move outside the viewport during rotation.

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Rotate the view as follows:


Rotation Method	Model Absolute
Rotation Angles	-30.0 10.0 15.0
Action	The view is rotated from the global zero starting position, -30o, 10o, and 15o about the global X, Y, and Z-axes, respectively.

Next, rotate the view again as follows:


Rotation Method--	Model Relative
Rotation Angles--	-10.0 -5.0 -5.0
Action--	The view will be rotated from the current starting position, -30o, -5o, and -5o about the global X, Y, and Z-axes, respectively.
End result:	The new view will have rotated a total of -40o, 5o, and 10o from the global staring position about the global axes.


Viewing>View From/To	Moving the Observer and Origin Positions

The position of two points, the view origin, or focal point, and the observer position (see Observation Point, 356) also influence the rotational orientation of a view.

In the Viewing> From/To dialog box, you can enter new coordinates for one or both of these points. If you move either one--but not the other-- the view will be rotated. If the coordinates of both points are changed by the same value, the view orientation remains unchanged.


Observation Point	The observation point, or observer position, represents the location of a person viewing the model in a perspective view. To change the observer position, enter new model space coordinates for the observation point.
Focal Point	The focal point is the view’s origin as well as the center of rotation when the view is rotated. To change the focal point location, enter new model space coordinate values.
Model Center	The model center is the geometric centroid of a viewport’s displayed geometric and finite element entities. If you changed the Focal Point coordinates in the dialog box, this button will return the focal point to the model center. The observer position will also change accordingly, in order to maintain the same view rotation.


Viewing>Scale Factors	Scaling a View

The Viewing>Scale Factors dialog box lets you enter specific scale factors to create a scaled view of the model.


Screen Scale Factors	The scale factors are applied in the X and Y directions of screen space. The center of scaling is the focal point.
Model Scale Factors	The scale factors are applied in the X, Y, and Z directions of model space. The center of scaling is the focal point.


Viewing>Named Views	Creating and Manipulating Named Views

With the Viewing>Named View Options command, you can create special views that can be named and stored for later use. When a named view is applied in a selected viewport, the view of the model will change to the same orientation, size, and clipping state defined for the named view. In this dialog box you can also rename and delete existing named views.


Current Viewport	Displays the name of the current viewport.
Select Named View	Lists all named views that exist in the database. Click on the view you want to display in the selected viewport.
Create View...	Creates and saves a new named view. After you positioned, rotated, and sized a view to achieve the effect you wanted, select this command then specify a new, unique view name in the subordinate dialog box.


Rename View...	Renames a selected named view. Select the existing view to be renamed and enter a new name in the subordinate dialog box.
Delete View...	Deletes a selected named view. You may confirm or cancel your request to delete a named view:


Viewing>Clipping/Perspective	Clippped Views

With the Clipping part of this command, you can control the location of the Z-clipping planes visually, as well as numerically in the dialog box.


Z Min/ Z Max	These show the extents of the view of the model in the positive and negative Z direction.
Front/Back Clipping Planes	These text boxes show the current position of the front and back clipping planes. Enter new values to change the position of either or both, then press Apply. You can also change the Z-clipping plane location by simply dragging the plane symbols to the left or to the right. The changes will apply to the model immediately, clipping it according to the new distances. The numerical values in the databoxes will update as well. Note that the front clipping plane distance must be greater than the back clipping distance, otherwise, the back clipping plane would end up in front of the front clipping plane. If you enter wrong values, a warning message will appear.


Viewing>Clipping/Perspective	Perspective Views

In the Perspective portion of the dialog box, you can modify the parameters of a perspective view, namely the location of the viewing plane and the observer position.


View Plane Distance	The distance between the viewing plane, which is normal to the Z-axis, and the focal point measured along the Z-axis. If this distance is zero, the viewing plane intersects the Z-axis at the focal point. A positive value places the viewing plane to the right of the focal point while a negative value moves it to the left of the focal point.
Observer Position	The distance between the focal point and the location of an observation point, measured along the Z-axis.

Managing the Parameters of Perspective Viewing


Controlling Distortion	The distance between the viewing plane and the observer position controls the distortion caused by perspective viewing. A greater distance will result in less distortion; as you decrease the distance the distortion will increase.
Visual Positioning	You can control distortion visually by dragging the screen symbols of the view plane and the observer to the left or to the right. With each position change the perspective view of the model will update immediately. Continue until the desired effect is achieved. Note that the numerical values in the data boxes will be modified as the respective symbols are repositioned.
Guidelines for View Plane Distance and Observer Position	When entering numerical values for these parameters, use the following considerations: • The observer position must be a non-zero positive number. • The distance of the observer position from the focal point must be greater than the model tolerance ( see Global Model Tolerance, 457). If you enter an unacceptable value, a warning message will be displayed. • The observer position distance must be greater than the view plane distance, otherwise, the view plane would end up behind the observer. If you enter an unacceptable value, a warning message will be displayed.


Viewing>Arbitrary Clipping	Creating and Managing User-defined Clipping Planes

The Viewing>Arbitrary Clipping dialog box accepts and displays all necessary information to create and manipulate arbitrary, or user-defined clipping planes.


Post/Unpost Clipping Planes	Lists all previously defined arbitrary clipping planes; the currently posted (active) clipping planes are highlighted. Click on a clipping plane to post it; click on a highlighted (posted) clipping plane to unpost it. The maximum number of clipping planes posted at any one time is six (use the Ctrl key while picking multiple entries).


Target Clipping Plane	The clipping plane affected by all modifications (e.g. rotation). To change the target plane from the one displayed, click the button to show all selectable planes then pick the new target plane.
Create...	Creates a new clipping plane. Brings up a text box in which you can enter the new name.
Delete...	Deletes a selected clipping plane.
Clipping Plane Attributes	Additional clipping plane features:
Move with Model	If ON, the clipping plane will retain its orientation relative to the model even when it is moved. When OFF, the orientation of the clipping plane is relative to the screen.
Display Direction Icon	The plane icon consists of: • a rectangle in the orientation defined in the Options below • X and Y directional axes • the plane’s normal represented by a directional arrow.
Options
	Incrementally rotates the clipping plane around its X or Y axis clockwise or counterclockwise. You set the rotation angle in the Rotate slide bar; each mouse click causes one rotation.
	Incrementally translates the clipping plane along its normal. You set the increment in model units in the Number of Units text box. Each mouse click moves the plane once.
Direction	As an alternative to rotating the clipping plane with the rotation icon, you can enter a new vector to change the direction of the clipping plane normal. Note that if you do use the rotation icon, the components of the normal vector will automatically update in this text box.
Location	As an alternative to moving the clipping plane with the translation icon, you can enter the model coordinate location of the clipping plane. Note that if you do use the icon to move the plane, the location coordinates will automatically update in this text box.