Sprite fire problems

[jjstanley]

Hi, a while back somebody here posted an fire HIP using sprites that was exactly what I wanted. I haved tried to duplicate this effect on my own particle system but can't get it to work right. The ramp expression in the scale SOP is not getting any data. Where does this reference in my new file? I have attached the original file(VOP_Fire) and my own.

Fire.zip

[Keyframe]

Heya JJ,

I've poked around your file briefly, and it seems to me that the culprit in this case is in fact, like you suspect the "ramp" channels that you are referencing in your various attribute sops.

exhelp for the chf command states:

float chf (string channel, float frame)

Will evaluate the channel at the frame specified.

And in your case, it seems that you are referencing channels named "ramp", which seems to imply that the "ramp*" channel not only exists, but exists in the current SOP - which I haven't been able to find.

As a solution, I would create those channels as spare channels, in the sop that they are being used, ie: in the frequency SOP, create 3 spare channels (CTRL + RMB -> Add Spare Channel) named ramp6, ramp7, and ramp8. Put down some animation curves, if you wish for them to animate, and keep your eye on the scale, as values that are too low will play some trick on ya.

Once these channels have been created, the "chf" command will have a value that it can pass to the procedure.

Hope this helps,

Cheers,

G

Hi, a while back somebody here posted an fire HIP using sprites that was exactly what I wanted. I haved tried to duplicate this effect on my own particle system but can't get it to work right. The ramp expression in the scale SOP is not getting any data. Where does this reference in my new file? I have attached the original file(VOP_Fire) and my own.

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