WorkBookFireworksProjectionsFaq < CMSPublic

CMSPublic Web>SWGuide>WorkBook>WorkBookFireworks>WorkBookFireworksProjectionsFaq (2018-04-26, AljaMrakTadel) (raw view)

---+ 3.4.5 Projections User Guide

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---++ Overview

Two types of projected views are supported in Fireworks.They can have different configuration, but in the *simplest case* the following formula can be applied:

   * *RPhi*, same as XY ortographic view :
   <verbatim>
x_screen = x
y_screen = y
</verbatim>

   * *RhoZ* projection is not YZ projection even in the simplest case. Screen X coordinate presents Z coordinate and Y screen coordiante presents distance to center with a sign of Y coordinate:
   <verbatim>
x_screen = z
y_screen = sqrt(x*x + y*y) * sgn(y)
</verbatim>


Bellow is a screen shot of ROOT demo showing the simplest case of the 2D projections. In left most  picture is a straight line and a geometry in 3D view.
Next to it are shown the same elements in projected RPhi and !RhoZ view.

 <img src="%ATTACHURLPATH%/simple.png" alt="Images from ROOT demo. Simplest projection" imalign="left" />

---++ Distorted 2D projections
*FishEye* distortion is used to enlarge central region of detector.  In the  picture bellow are example of 2D projected views with distortion value of 3.

<img src="%ATTACHURLPATH%/distUnlim.png" alt="Images from ROOT demo. Distorted projection"  imalign="left" />


---++ Fixed Radius in distorted projections
Distortion can be locked above defined radius.If you compare this pictures with the one above you can see the outer layer of geometry is less distorted.

<img src="%ATTACHURLPATH%/distLim.png" alt="Images from ROOT demo. Distorted projection with fixed radus 130 cm"  imalign="left" />

---++ More Info
Original idea for the projections was taken from *H. Drevermann* article [[https://cds.cern.ch/record/295024/files/p17.pdf][Can We See What We Want to See ?]]

#ReviewStatus
---++ Review status

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| *Reviewer/Editor and Date (copy from screen)* | *Comments* |
| AntonioMorelosPineda - 17 Apr 2013 | Upgrade to workbook style |
| Main.AljaMrakTadel  -11 Jul 2012 | Created. | 

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Upgrade to workbook style, A.Morelos,17-Apr-2013

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<!-- %REVIEW% Main.AljaMrakTadel - 08 Mar 2011 -->
%REVIEW% Main.AntonioMorelosPineda - 17 Apr 2013

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who	Comment
gif	62966_3274141.gif	r1	manage	3.8 K	2008-10-03 - 17:20	DmytroKovalskyi	Rho-Z view of a track with significant impact parameter
gif	barrel_sta_muon.gif	r1	manage	9.8 K	2008-08-17 - 23:14	DmytroKovalskyi	barrel stand alone muon (CRUZET3)
png	distLim.png	r1	manage	55.5 K	2009-12-08 - 20:47	AljaMrakTadel	fixedR
png	distUnlim.png	r1	manage	57.2 K	2009-12-08 - 20:48	AljaMrakTadel	distUnlim
png	simple.png	r1	manage	55.7 K	2009-12-08 - 20:41	AljaMrakTadel	Simple non-distorted projection