# Trail effect
**URL:** https://forum.kirupa.com/t/trail-effect/265142
**Category:** flash
**Created:** [July 4, 2008, 4:09pm UTC](https://forum.kirupa.com/t/trail-effect/265142 "2008-07-04T16:09:36Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@RebuiltJorge](https://forum.kirupa.com/u/RebuiltJorge)
#### Post date: [July 4, 2008, 4:09pm UTC](https://forum.kirupa.com/t/trail-effect/265142/1 "2008-07-04T16:09:36Z")
I am trying to dublicate one of those navy radar screen, where the line rotates around inside of a circle, furthermore, it creates a trail effect of the line, i am having a hard time figuring out how to dublicate this effect, i started to look into copying pixels from bitmapData, this works fine if i am moving something up or down,left or right, but my line is rotating around, how can i dublicate the line while it is rotating,
---
### Author:  [@sekasi](https://forum.kirupa.com/u/sekasi)
#### Post date: [July 4, 2008, 4:13pm UTC](https://forum.kirupa.com/t/trail-effect/265142/2 "2008-07-04T16:13:34Z")
I would do a bitmapdata that snapshots your line enter\_Frame and then blurs it constantly.
---
### Author:  [@sekasi](https://forum.kirupa.com/u/sekasi)
#### Post date: [July 4, 2008, 4:47pm UTC](https://forum.kirupa.com/t/trail-effect/265142/3 "2008-07-04T16:47:35Z")
Started thinking about it and maybe that’s not the best route… I tried coding it up real fast, is this what you were thinking of? 😕
[http://www.erikhallander.com/dev/as3/radar.html](http://www.erikhallander.com/dev/as3/radar.html)
---
### Author:  [@Iamthejuggler](https://forum.kirupa.com/u/Iamthejuggler)
#### Post date: [July 4, 2008, 6:32pm UTC](https://forum.kirupa.com/t/trail-effect/265142/4 "2008-07-04T18:32:28Z")
The blur isn’t quite what a radar looks like, but doing a simple fade with a colormatrixfilter would give lines rather than a shadow effect. I played around with it but didn’t come up with anything all that convincing apart from creating a transparent png of the line and it’s shadow and rotating that around, which is a bit of a hack!
---
### Author:  [@nikefido](https://forum.kirupa.com/u/nikefido)
#### Post date: [July 5, 2008, 3:19am UTC](https://forum.kirupa.com/t/trail-effect/265142/5 "2008-07-05T03:19:26Z")
[quote=sekasi;2353674]Started thinking about it and maybe that’s not the best route… I tried coding it up real fast, is this what you were thinking of? 😕
[http://www.erikhallander.com/dev/as3/radar.html[/quote]](http://www.erikhallander.com/dev/as3/radar.html%5B/quote%5D)
If you can’t get exactly what you want from that (it’s pretty close) i suggest making a round mask for the area you want to show ( you can make a gradient mask!). that way you can eliminate all the “extra” trail you don’t want there.
edit: i also suggest playing with a colormatrixfilter - allows you do decrease the visible area of the blur. This use is coverd on [gotoandlearn.com](http://gotoandlearn.com) - check out the video on Advanced Filter Effects - he goes over it’s use in that video. (and if not in there, then the newer one about sound spectrum analysis).
---
### Author:  [@RebuiltJorge](https://forum.kirupa.com/u/RebuiltJorge)
#### Post date: [July 5, 2008, 10:47am UTC](https://forum.kirupa.com/t/trail-effect/265142/6 "2008-07-05T10:47:24Z")
sekasi, that is kinda of what i’m looking, would you mind if i take a look at ur code, thanks, colormatrix filter sounds interesting too, i will look into it, thanks everyone