[Closed] viewport grapping , redraw issue ?

well , i managed to do viewport capturing resizing and saving via this

db = viewport.getViewportDib()
 db.filename =(getdir #scene ) +"_dib.bmp"
 save db
 tx = bitmaptexture bitmap:db
 wincrm=150.0/db.width
 hincrm=150.0/db.height
 bb = bitmap (db.width*wincrm) (db.height*hincrm) 
 ff=rendermap tx into:bb size:([db.width,db.height]*hincrm) filter:on display:on
 ff.fileName=(getdir #scene) + "_dibM.bmp"		
 save ff

the idea is that i wanted to grap viewport through another camera in the scene -or even temporarily created- while being in the same vieport without having to do viewport redrawing , i already did disabled viewport redrawing but it captured what is in the current viewport , so how to do this ?