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View Full Version : Particle Info: Long standing bug or known Limitation?



kahalany
12-13-2014, 11:46 AM
Hi.
Using the node editor, I've been trying to link particle velocity to its corresponding instance size with no success. It seems like there is no individual particle output as each and every particle's velocity is being averaged together and output one single value to the instance generator instead of each particle's unique value. This resulting in single sized instances regardless of their velocity. Apparently the same happens with other parameters in the Particle Info node.

Is this a known limitation of LW's particle system?

Sensei
12-13-2014, 11:58 AM
Show screen-shot of node editor, and/or scene.

kahalany
12-13-2014, 12:15 PM
126048

Here you go. I used Vector Scalar to limit the output to the Y channel as this is the only channel used for velocity. The Initial Velocity is 10 (Bottom particles) and goes down to around 1.4 before the particle dies off.

XswampyX
12-13-2014, 12:39 PM
I think you need to attach your scale value to scale min, scale max...

If they are both set a 100% then the scale won't/can't change?

Sensei
12-13-2014, 12:49 PM
Of course turned on "Use Nodes"? Just asking, because default it's off..

kahalany
12-13-2014, 12:53 PM
Nope. Tried that, and every other trick I could think of, including baking the particles into various parameters saving formats and streaming them from cache. Nothing.
Apparently it's not even averaging. I lowered the particles rate to 2 particles per sec. What happens is no matter how many particles you have in your scene at a certain time ONLY ONE IS EVALUATED (probabaly the one with the lower index) and its parameters are fed to ALL the instances. Once this "leading" particle dies off the next one takes the lead and its values are evaluated and applied to the instances.

So by now I'm pretty sure it's related to the particle system architecture. If it's an overlooked bug it's a pretty major one. If it's an architecture limitation, well that's even worse..

XswampyX
12-13-2014, 01:05 PM
Works here... ?
You have assigned the Particle info node to your emitter?

http://forums.newtek.com/attachment.php?attachmentid=126050&d=1418501046

126050

kahalany
12-13-2014, 02:05 PM
Works here... ?
You have assigned the Particle info node to your emitter?

http://forums.newtek.com/attachment.php?attachmentid=126050&d=1418501046

126050

Are you using LW's built in Particle Info node? Mine looks radically different than yours.

Sensei
12-13-2014, 02:17 PM
Are you using LW's built in Particle Info node? Mine looks radically different than yours.

It's from DP Kit.

kahalany
12-13-2014, 02:23 PM
Ok. Indeed, using DP's Particle Info node fixes this problem when selecting Nearest particle mode.
Thanks, XswampyX. And yet again Dennis saves the day.
Interestingly, you can pinpoint LW's own ParticleInfo node bug with DP's: Simply choose index or ID mode (but do not connect LW's ID index to the DP's index input) and you get the exact same problem. LW's ParticleInfo node simply do not feed the instance system more than one index at a given time.

Sensei
12-13-2014, 02:31 PM
NT Particle Info is meant to return particle data for particle identified by some internal info.

While DP Kit is searching for particle by position (Spot > World Position probably), or giving particle data for given input index.