View Full Version : sprite particles and camera


twilightened
02 February 2008, 03:08 PM
Hi,

given a camera. A sprite particle system. I need that as the sprite particles travel towards the camera, that the size of the sprite particles remain constant as they travel. How is it possible.

BRgds,

kNish

ctp
02 February 2008, 05:18 PM
You can use something like this in your expressions:


float $camPos[] = `xform -q -translation camera1`;

vector $particlePos = position;

float $distance = mag((<<$camPos[0],$camPos[1],$camPos[2]>>) - (<<$particlePos.x,$particlePos.y,$particlePos.z>>));

spriteScaleXPP = spriteScaleYPP = $distance * 0.2;


Make sure to have added the spriteScaleXPP and spriteScaleYPP perParticle attributes.

twilightened
02 February 2008, 10:29 AM
Hi,

Thank you for your reply. It has been useful.


How is it possible to use a smoothstep in this function to get a curve formation as the sprite particles travel.

BRgds,

kNish

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02 February 2008, 10:29 AM
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