set cut_paste_input [stack 0]
version 12.2 v4
push $cut_paste_input
ParticleExpression {
 temp_name0 camVec
 temp_expr0 "v( \[value camPosition.x],\[value camPosition.y],\[value camPosition.z])"
 temp_name1 length
 temp_expr1 "mag(pos - camVec)"
 temp_name2 aaa
 temp_expr2 "1/(\[value maxDist]-\[value minDist])"
 temp_name3 bbb
 temp_expr3 "-(\[value minDist]/(\[value maxDist]-\[value minDist]))"
 colexpr v((aaa*length+bbb)<0?0:(aaa*length+bbb)>1?1:(aaa*length+bbb),(aaa*length+bbb)<0?0:(aaa*length+bbb)>1?1:(aaa*length+bbb),(aaa*length+bbb)<0?0:(aaa*length+bbb)>1?1:(aaa*length+bbb))
 opacityexpr (aaa*length+bbb)<0?0:(aaa*length+bbb)>1?1:(aaa*length+bbb)
 name ParticleFadeToCamera
 selected true
 xpos 164
 ypos -53
 addUserKnob {20 User}
 addUserKnob {13 camPosition}
 addUserKnob {7 minDist R 0 1000}
 minDist 1000
 addUserKnob {7 maxDist}
 maxDist 15000
}