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
> }
>
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