Hehe, i had over simplified a bit too much my problem with this example ! At least there's not problem with it, fortunately, just with me ! Thanks Tim
----- Mail original ----- De: "Tim Walker" <[email protected]> À: "Nuke user discussion" <[email protected]> Envoyé: Mardi 15 Janvier 2013 13:20:43 Objet: Re: [Nuke-users] Particles Expression behaves widly Give this a go. rejigged the particle setup a little just to prove it works: set cut_paste_input [stack 0] version 6.3 v5 push $cut_paste_input ParticleEmitter { start_frame 128 lifetime 100 velocity 0.065 spread 0.5 name ParticleEmitter6 selected true xpos -58 ypos -90 } ParticleWind { to {0 0 0} drag 0.16 "air resistance" true name ParticleWind1 selected true xpos -58 ypos -64 } ParticleExpression { sizeexpr mag(vel) name ParticleExpression1 selected true xpos -58 ypos -9 } On Tue, Jan 15, 2013 at 11:47 AM, < [email protected] > wrote: Hi Nukers, I just want to drive the size of the particles by their speed, but even with a simple example it gives weird results. Some particles goes big although the expression must (should?) just divide the size. The second expression node clamp the size to avoid this, it works for some reasonable particles but not for the wild ones. With sphere particles i've checked that the big ones are effectively big and not just in front of the camera. Is there anybody here with an explanation for that ? Cheers philhub set cut_paste_input [stack 0] version 6.3 v4 Constant { inputs 0 color 0.3 name Constant6 selected true xpos -1804 ypos 222 } Sphere { uniform_scale 0.5 name Sphere1 selected true xpos -1804 ypos 294 } push $cut_paste_input ParticleEmitter { start_frame 128 lifetime 100 velocity 0.2 spread 0.5 name ParticleEmitter6 selected true xpos -1797 ypos 371 } ParticleGravity { to {0 -0.01 0} name ParticleGravity7 selected true xpos -1797 ypos 408 } set N31783080 [stack 0] ParticleExpression { temp_name0 newSize temp_expr0 1/y(vel+.01)/300 colexpr .5 opacityexpr .5 sizeexpr newSize<.05?newSize:.05 name ParticleExpression5 selected true xpos -1724 ypos 471 } push $N31783080 ParticleExpression { temp_name0 newSize temp_expr0 1/y(vel+.01)/300 colexpr .5 opacityexpr .5 sizeexpr newSize name ParticleExpression7 selected true xpos -1842 ypos 472 } _______________________________________________ Nuke-users mailing list [email protected] , http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users _______________________________________________ Nuke-users mailing list [email protected], http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users _______________________________________________ Nuke-users mailing list [email protected], http://forums.thefoundry.co.uk/ http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-users
