I don't know the author of this script, but I use it every day to set the aspect ratio of all selected events.

===============

// "Match Output Aspect" on all selected video events.

// No selection = ALL



import System.Windows.Forms;

import Sony.Vegas;



var zero : int = 0;



function GetSelectionCount (mediaType)

{

    var cTracks   = Vegas.Project.Tracks.Count;

    var cSelected = zero;

    var ii; 

    

    for (ii = zero; ii < cTracks; ii ++)

    {

        var track = Vegas.Project.Tracks[ii];

        

        if (track.MediaType == mediaType)

        {            

            var eventEnum : Enumerator = new Enumerator(track.Events);

        

            while ( ! eventEnum.atEnd() ) 

            {            

                if (eventEnum.item().Selected)

                {                

                    cSelected ++;       

                }

                

                eventEnum.moveNext();                            

            }

        }                                  

    }

    

    return cSelected; 

}



function GetActiveMediaStream (trackEvent : TrackEvent)

{

    try

    {

        if ( ! trackEvent.ActiveTake.IsValid())

        {

            throw "empty or invalid take";

        }                

        

        var media = Vegas.Project.MediaPool.Find (trackEvent.ActiveTake.MediaPath);

        

        if (null == media)

        {

            throw "missing media";

        }

        

        var mediaStream = media.Streams.GetItemByMediaType (MediaType.Video, trackEvent.ActiveTake.StreamIndex);        

        

        return mediaStream;

    }

    catch (e)

    {

        //MessageBox.Show(e);

        return null;

    }    

}



function MatchOutputAspect (keyframe : VideoMotionKeyframe, dMediaPixelAspect : double, dAspectOut : double)

{

    var keyframeSave = keyframe;

        

    try

    {

        var rotation = keyframe.Rotation;    

        

        // undo rotation so that we can get at correct aspect ratio.

        //

        keyframe.RotateBy (-rotation);



        var dWidth         = Math.abs(keyframe.TopRight.X   - keyframe.TopLeft.X);

        var dHeight        = Math.abs(keyframe.BottomLeft.Y - keyframe.TopLeft.Y);

        var dCurrentAspect = dMediaPixelAspect * dWidth / dHeight;

        var centerY        = keyframe.Center.Y;

        var centerX        = keyframe.Center.X;        

        

        var dFactor;

        

        var bounds = new VideoMotionBounds(keyframe.TopLeft, keyframe.TopRight, keyframe.BottomRight, keyframe.BottomLeft);



        if (dCurrentAspect < dAspectOut)

        {

            // alter y coords            

            dFactor = dCurrentAspect / dAspectOut;            

                        

            bounds.TopLeft.Y     = (bounds.TopLeft.Y     - centerY) * dFactor + centerY;

            bounds.TopRight.Y    = (bounds.TopRight.Y    - centerY) * dFactor + centerY;

            bounds.BottomLeft.Y  = (bounds.BottomLeft.Y  - centerY) * dFactor + centerY;

            bounds.BottomRight.Y = (bounds.BottomRight.Y - centerY) * dFactor + centerY;            

        }

        else

        {                          

            // alter x coords

            dFactor = dAspectOut / dCurrentAspect;            

                        

            bounds.TopLeft.X     = (bounds.TopLeft.X     - centerX) * dFactor + centerX;

            bounds.TopRight.X    = (bounds.TopRight.X    - centerX) * dFactor + centerX;

            bounds.BottomLeft.X  = (bounds.BottomLeft.X  - centerX) * dFactor + centerX;

            bounds.BottomRight.X = (bounds.BottomRight.X - centerX) * dFactor + centerX;

        }

        

        // set it to new bounds

        keyframe.Bounds = bounds;

        

        // restore rotation.        

        keyframe.RotateBy (rotation);

        

    }

    catch (e)

    {

        // restore original settings on error

        keyframe = keyframeSave;

        MessageBox.Show("MatchOuput: " + e);

    }    

}





var dWidthProject  = Vegas.Project.Video.Width;

var dHeightProject = Vegas.Project.Video.Height;

var dPixelAspect   = Vegas.Project.Video.PixelAspectRatio;

var dAspect        = dPixelAspect * dWidthProject / dHeightProject;

var cSelected      = GetSelectionCount (MediaType.Video);





var cTracks = Vegas.Project.Tracks.Count;

var ii;



for (ii = zero; ii < cTracks; ii ++)

{

    var track   = Vegas.Project.Tracks[ii];

    

    if (! track.IsVideo())

    {

        continue;

    }

    

    var eventEnum : Enumerator = new Enumerator(track.Events);        

    

    while ( ! eventEnum.atEnd() ) 

    {

        var trackEvent : TrackEvent = eventEnum.item();                                    

        

        if ( !cSelected || trackEvent.Selected )

        {                                            

            var mediaStream = GetActiveMediaStream (trackEvent);                

            

            if (mediaStream)

            {                                    

                var videoStream = VideoStream (mediaStream);

                    

                var dMediaPixelAspect = videoStream.PixelAspectRatio;

                var videoEvent        = VideoEvent(eventEnum.item());    

                var keyframes         = videoEvent.VideoMotion.Keyframes;

                

                var cKeyframes = keyframes.Count;

                var jj;

                

                for (jj = zero; jj < cKeyframes; jj ++)

                {

                    MatchOutputAspect (keyframes[jj], dMediaPixelAspect, dAspect);                                                                     

                }

            }

        }

        

        eventEnum.moveNext();

    }

}





Vegas.UpdateUI();

I've never used a script before...how do I use that?

cut & paste this into notepad , save it with any name that you like, change the extension from .txt to .js, put it into your ProgramFiles/Sony Vegas/Scripts folder and reopen Vegas. Now it will show up in Vegas and will apply the project aspect ratio to any selected events
Anyway - it is the first time I have done such a thing - it worked for me - very useful....

The script was written by Sony. It can be found HERE along with a few other scripts and scripting information. Please rename it to "Matchaspect" instead of leaving the first "M" lowercase.

Other scripts also have this functionality built-in including both Excalibur 4 and Ultimate S. If you haven't used scripts at all, I would recommend you check them out.

Got that and see other scripts in the Script Menue Folder but how do I actually apply the script to an event?

//Garo