The commands I used are:
(with no visible particles):
/summon vex -229.0 3 103 {NoGravity:0b,Invulnerable:1b,Tags:["DarkCloudBase"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Passengers:[{id:"minecraft:area_effect_cloud",Particle:"block air",ReapplicationDelay:0,Radius:10f,RadiusPerTick:0f,Duration:9999,WaitTime:0,Motion:[0.0,0.0,0.4],Tags:["DarkCloud"],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}],Effects:[{Id:7b,Amplifier:1b,Duration:1,ShowParticles:0b},{Id:9b,Amplifier:0b,Duration:100,ShowParticles:0b},{Id:15b,Amplifier:0b,Duration:40,ShowParticles:0b},{Id:20b,Amplifier:1b,Duration:40,ShowParticles:0b}]}]}(Basically was a moving wall of particles, in a corridor, that kills you)
And:
execute as @e[tag=DarkCloudBase] run data merge entity @s {Motion:[0.0d,0.0d,0.05d]}(on a repeating command block)
I am using a vex, rather than an armor_stand, because the Marker:1b tag no longer allows movement through walls and things. I notice that it also goes backwards and down slowly when its Motion is set to 0.
Even with no interaction from a survival mode player, it still randomly goes against its constantly set motion.
EDIT: Sorry the command comes out so big..
Attachments
Comments 5
Cannot reproduce. The vex moves slow and steady, and directly straight. Perhaps you have another command that's interfering with that?
No external commands that could interfere, and I tried it on a new world with similar results. I have a video showing that it still happens on a new world.
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The quality is bad, but the only command blocks are for the x-position-to-score, the kill-all-non-players, the one that gives the vex the motion, and one to summon the vex stack.
It has no positions of any type stored in its entity data, so I have no idea why it goes off course. Almost half a block after 20 or so blocks, sometimes varies.