View Full Version : popping particle clouds

03 March 2008, 08:48 PM

i found discriptions of this problem here in the forum but no solutions:
i made a sun that emits cloud particles, using a ramp to control the life transparancy. that seems to work fine so far, but in the rendering the light popps as you can see in this quicktime:

can someone tell me how to solve that problem?


03 March 2008, 11:30 AM
Hi ,

Just a idea , you render your glow directly in 3d or you apply it in post ?
I know that with glow you can have some issue. If you render your glow in 3d , check the glow shader in the hypershade , and turn off the Auto Exposure . it will change the look of your glow , but it will become more "stable" ...

Second idea , check that your particleSamplerInfo is correctly plug in your life transparency..

Here my 2 cents...

Hope it helps !

Ps :Perhaps you should post you scene .



03 March 2008, 01:32 PM
thanks for your reply.

auto exposure is turned off and i also made test-renders without glow. so its not that.
as far as i can see the particleSamplerInfo Node is plugged in correctly to the Transparancy. however i'm not sure about that point.

here is the scene:
sunflickerscene (

maybe you aswell have better ideas how to make the sun burn.


03 March 2008, 04:07 PM
Hi ,
So , first one advice , never use the particleCloud1 , like never use the lambert1.
it coulb be dangerous if you mix scenes or if you want import effect , or things like that. :)

And the particlesSampleInfo , isn t correctly plug :),( perhaps because you use the particleCloud1 :rolleyes: )
You will see if you create a new particleCloud , and in life transparency , plug a ramp , and you will see , is not the ramp plug but a particlesSamplerInfo , and in this case it will work ! ;).
So ,like that you have no popping fade on your particles , but you have still one in the emission on your particles , because your rate is really low , and the particles (in end life ) react on the emission of the other because the glow is really strong , and your particles appear by paket and really incandescent in one frame so the glow "react" on this .

And apparently MentalRay don t like that , so try all of this and render in (if you can) maya software , in a separate pass is always better ;) ...

Hope to be understandable ! ^^ :rolleyes:
My english isn t really good...

Ps: i attach your scene with this little modifications

Hope it helps



03 March 2008, 07:39 PM
thank you so much for your very understandable advice :thumbsup:

maya software does the job right :applause:
i now was fiddling around for over a week and made about a hundred renders. i never had the idea to just try it with the maya renderer..

there is still a barely noticeable popping from time to time, which but doesn't disturb during the animation. but couldn't it be possible to emit the particles from inside the sun? ..or would they then pop out of the sun..? -just for interest. really i'm happy already :)

thanx allot once more


03 March 2008, 07:42 AM
Try ramp lifeTransparency, make the top and bottom total white, this will make particle birth and die with total transparency

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03 March 2008, 07:42 AM
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