Plancton Particle: Intelligent Solution for Huge Scene Movement?

# 1 26-03-2011 , 05:39 PM

Registered User
Join Date: Jul 2006

Posts: 4

Plancton Particle: Intelligent Solution for Huge Scene Movement?

Hi! I actually work on some underwater shots, and have created
a simple sphere volume emitter with instances pointing to the camera.

the camera has a fulldome lens attached and is placed in the center of
the emitter. a volume field kills particles near the camera (to avoid
getting extreme huge planctons on screen)

that works fine for stills, where the camera isnt moving. but i have
some shots, where the camera is following a submarine,… and the movement
is very long. instead of creating a field of millions of planction it
would be great to find a solution, where just the plancton surrounding
the center camera is visible.

do you have ideas, how to solve this problem?!?

btw, i dont wanna just make them invisible, i just want to make them appear, if they are near the camera, you know?!

thanks alot for your time & Help!

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# 2 26-03-2011 , 07:16 PM

The thin red line
Join Date: Aug 2009

Location: England

Posts: 4,472

Is the problem that the emitter is in the middle of the camera and when you move farward the partical are being left behind, may be move the emitter some distance in front of the camera...........dave

Avatar Challenge Winner 2010

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# 3 31-03-2011 , 10:55 AM

Moderator
Join Date: May 2003

Location: London

Posts: 1,001

You can always emit from the camera frustum so particles arn't born too far ahead where you won't seem them, there are a few scripts around that do that. Though something simpler may be better as this will only work if the particles dont re-appear.

Yyou could have the source a reasonable distance from the camera that moves with the camera and put your kill box behind the camera.

Arn't you getting popping as they are culled when close to the camera?

You would need something like this (ignoring terriple syntax):
float $cameraWorld[] = (`xform -q -ws -rp "pSphere1"`); (this just ensures you get the actual position rather than the channel information which is useless if you have frozen transforms at any poin)
vector $cameraPos = <<$cameraWorld[0], $cameraWorld[1], $cameraWorld[2]>>;
float $displacement = mag(position - $cameraPos);
float $fade = linstep(0, 100 , $displacement); ( 0 - 100 can be set to whatever your range is)
$opacityPP =$opacityPP * $fade;

You could always not bother with the fade and use a ramp driven by $displacement instead with a range thats 0 - fade distance. then mult that with opacityPP seperately for more intuative control.

FX supervisor - double negative

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Plancton Particle: Intelligent Solution for Huge Scene Movement?

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