positioning techniques

8/13/2019 Positioning Techniques

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Interactive InputTechniques


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Interactive Input Techniques

Basic positioning methods

Constraints

Grids

Gravity fields

Rubber-band methods

Sketching

Dragging


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Positioning techniques

There are various techniques used for positioning.

Positioningmeans location, which is one of the basic

graphical input techniques.

For geometrical modelling, positioning is very important,

as the user frequently designs a new element of the model

or repositioning an existing one.

While working on the screen the position is used to insert a

symbol or to indicate the end point of a line or three points

on a curve.


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For positioning the desired spot on the screen , the cursor ortracking cross is moved to that location and then the

information is passed to the computer memory by pressing a

button or key.

There are positioning constraints which can be overcome by

using symbols guidelines, feedback and the use of rubber

band techniques.


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Basic positioning techniques

Used to specify a location for an object or a character

string The cursor is moved to the desired location.

A button is pressed to fix the object at this location.


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Used to draw lines


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Used to place the cursor at a predetermined position


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Constraints

Used to achieve predetermined orientations and

alignments

Common constraints

Horizontal alignment


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Vertical alignment


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Grids

Used to round coordinates positions to the nearest grid

intersection


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Useful for positioning and aligning objects and text

Grids can be displayed or invisible


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Gravity field

Used to connect a new line to a previously drawn line

Normally the gravity field is not displayed


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Rubber band Methods

Used to construct and position straight lines


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Used to construct circular arcs


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Used to scale objects

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Used to distort objects by allowing only the line

segments attached to a single vertex to change

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Sketching

Uses rubber-band methods to create objects consisting

of connected line segments


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Uses stroke techniques to create curved figures

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A variety of brushes can be provided

Different thicknesses

Different textures

Different colors (including background) Even patterns

Continue


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Dragging

Used to reposition objects

Select an object from the menu

Position the object

Release the objects


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Thank you

positioning techniques

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