Single stray flash observed at initial emission when PSYS_PART_FOLLOW_SRC_MASK flag is set, and the PSYS_SRC_BURST_RADIUS rule is therefore disabled, i.e. zero, as per the wiki, no matter whatever value is found in this latter parameter. Perfect coding practise would see the radius explicitly set to zero, but in the event that the the value has been left non-zero and simply relied upon as being disabled, there is a single emission at initial burst which results in a flash at a distance of the radius set. When a timer is running this will occur once at each tick of the timer. Ideally, the radius should indeed be set to zero, which removes the problem, but as the radius value is disabled for the case where the PSYS_PART_FOLLOW_SRC_MASK is set, and correctly does so generally, the initial flash emission should not be happening either and is likely causing visual glitches in-world. To Repro : Drop a simple particle emission into a prim such as: default { state_entry() { llSetTimerEvent(0.25); } timer() { llLinkParticleSystem(LINK_THIS, [ PSYS_PART_FLAGS, 0 | PSYS_PART_EMISSIVE_MASK | PSYS_PART_INTERP_COLOR_MASK | PSYS_PART_INTERP_SCALE_MASK | PSYS_PART_FOLLOW_SRC_MASK | PSYS_PART_FOLLOW_VELOCITY_MASK, PSYS_SRC_PATTERN,PSYS_SRC_PATTERN_EXPLODE, PSYS_PART_MAX_AGE,0.5, PSYS_PART_START_COLOR,<1.0, 1.0, 1.0>, PSYS_PART_END_COLOR,<1.0, 1.0, 1.0>, PSYS_PART_START_SCALE,<0.5, 0.5, 1.0>, PSYS_PART_END_SCALE,<0.8, 0.8, 1.0>, PSYS_SRC_BURST_RATE,0.1, PSYS_SRC_ACCEL,<0.0, 0.0, 0.0>, PSYS_SRC_BURST_PART_COUNT,1, PSYS_SRC_BURST_RADIUS,0.5, PSYS_SRC_BURST_SPEED_MIN,0.1, PSYS_SRC_BURST_SPEED_MAX,0.2, PSYS_SRC_TARGET_KEY,(key)"", PSYS_SRC_INNERANGLE,0, PSYS_SRC_OUTERANGLE,0.5, PSYS_SRC_OMEGA,<0.0, 0.0, 0.0>, PSYS_SRC_MAX_AGE,0.00, PSYS_SRC_TEXTURE, "dcab6cc4-172f-e30d-b1d0-f558446f20d4", PSYS_PART_START_ALPHA,1.0, PSYS_PART_END_ALPHA,0.0, PSYS_PART_START_GLOW,0.0, PSYS_PART_END_GLOW,0.0 ]); } } Observe the stray emission at each tick of the timer: https://gyazo.com/5f8a6b9a8e4c5a657d3d3d0aaa13ce36 Set PSYS_SRC_BURST_RADIUS = 0.0 Observe correct behaviour https://gyazo.com/1a5612c42c44afb0f50ec06b79fe262d
