[vtkusers] Speed of zoom

[Lisa Avila]

When you "zoom" by moving the camera closer / farther from the focal point 
(called "dolly") this will happen. The movement is a fraction of the 
current distance from the camera position to the focal point - hence when 
you get really close to the focal point you are only moving very small 
distances.

An alternate way to "zoom" is to change the view angle - here you can get a 
smoother effect, but keep in mind that your camera doesn't actually move 
(which can be confusing when a user tries to navigate through the scene 
using your "zoom" functionality)

Lisa


At 11:25 AM 4/21/2004, James C. Robinson wrote:
>Dear All,
>
>I may have posted this query already (as it is an ongoing wish list member).
>I refer to the use of the mouse for zooming, panning etc. in a window.
>Sometimes, for reasons I have not quite figured out (although I suspect it
>has something to do with either the position of the camera focal point or
>the object origin) the zoom capability (or pan) slows down such that a large
>movement in the mouse cursor position results in a very small change (zoom
>or pan) on the view. That is, I might be zoomed in to a certain distance
>from an object (or detail of an object) and, depending on "how" I zoomed in,
>the subsequent zoom power can vary from strong to very slight.
>
>Has anybody (a) any idea what I am talking about and (b) any suggestions as
>to what is going on and what one can do to control this apparently (though I
>am sure it is not) arbitrary behaviour. NB: I cannot find any detailed
>reference to the interactor type control involved here in the doc (it refers
>only to "dolly" etc. when explaining zooming).
>
>Many thanks,
>
>Jim
>
>______________________
>
>James C. Robinson, PhD,
>Chartered Engineer,
>Kepler Simulation Systems Ltd.,
>42 Rivergrove,
>Glanmire, Co. Cork,
>Eire
>
>Tel:         +353-21-4822028
>Tel:         +353-87-2393010
>Fax:        +353-21-4822028
>E-mail:     j.robinson at kepler-systems.com
>______________________
>
>
>
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