I am new in Blender and I want to get the velocity of a moving object. I am not a programmer and I guess I have to create a Python code. Can you maybe help me with it, because I don't even know the libraries of python or how to use them? Can you show me a way to program a "get velocity" code or node? I will really appreciate a finger pointing in the right direction.
Thank you very much
There are 2 velocities possible - linear and angular.
Here is a possibility how you can get the linear velocity.
First - create a rigid body simulation. In my attached example I let a sphere fall down to a plane. Then select the sphere and go to Object -> Rigid Bodies -> bake keyframes.
This is needed and makes Blender to save the locations of the sphere.
Then run this script:
# before use you have to do: Object -> Rigid Body -> Bake to keyframes
import bpy
from mathutils import Vector
def distance_line(point1: Vector, point2: Vector):
return (point2 - point1).length
object = bpy.data.objects["Sphere"]
bpy.context.scene.frame_set(1)
prev_location = object.location.copy()
for frame in range(1, 50, 1):
bpy.context.scene.frame_set(frame)
new_location = object.location
distance = distance_line(new_location, prev_location)
distance_vec = new_location - prev_location
time = frame / 50
velocity = distance_vec / time
speed = distance / time
print("frame", frame, "speed = ", speed, "velocity = ", velocity)
prev_location = new_location.copy()
frame 1 speed = 0.0 velocity = <Vector (0.0000, 0.0000, 0.0000)>
frame 2 speed = 0.23405551788968906 velocity = <Vector (0.0000, 0.0000, -0.2341)>
frame 3 speed = 0.43941338677345454 velocity = <Vector (0.0000, 0.0000, -0.4394)>
frame 4 speed = 0.5417287333633571 velocity = <Vector (0.0000, 0.0000, -0.5417)>
frame 5 speed = 0.6028270774994956 velocity = <Vector (0.0000, 0.0000, -0.6028)>
frame 6 speed = 0.6433208687131368 velocity = <Vector (0.0000, 0.0000, -0.6433)>
frame 7 speed = 0.6720406668526785 velocity = <Vector (0.0000, 0.0000, -0.6720)>
frame 8 speed = 0.6933987244921247 velocity = <Vector (0.0000, 0.0000, -0.6934)>
frame 9 speed = 0.7098515774669812 velocity = <Vector (0.0000, 0.0000, -0.7099)>
frame 10 speed = 0.7228732105570549 velocity = <Vector (0.0000, 0.0000, -0.7229)>
frame 11 speed = 0.733395053418168 velocity = <Vector (0.0000, 0.0000, -0.7334)>
frame 12 speed = 0.7420480364275706 velocity = <Vector (0.0000, 0.0000, -0.7420)>
frame 13 speed = 0.7492560713914638 velocity = <Vector (0.0000, 0.0000, -0.7493)>
frame 14 speed = 0.7553347503142805 velocity = <Vector (0.0000, 0.0000, -0.7553)>
frame 15 speed = 0.7605091772460675 velocity = <Vector (0.0000, 0.0000, -0.7605)>
frame 16 speed = 0.764947394702861 velocity = <Vector (0.0000, 0.0000, -0.7649)>
frame 17 speed = 0.7687800204009462 velocity = <Vector (0.0000, 0.0000, -0.7688)>
frame 18 speed = 0.7721099531842459 velocity = <Vector (0.0000, 0.0000, -0.7721)>
frame 19 speed = 0.7750134781744401 velocity = <Vector (0.0000, 0.0000, -0.7750)>
frame 20 speed = 0.7775571987736258 velocity = <Vector (0.0000, 0.0000, -0.7776)>
frame 21 speed = 0.7797919613901602 velocity = <Vector (0.0000, 0.0000, -0.7798)>
frame 22 speed = 0.78175962590308 velocity = <Vector (0.0000, 0.0000, -0.7818)>
frame 23 speed = 0.6596611896169278 velocity = <Vector (0.0000, 0.0000, -0.6597)>
frame 24 speed = 0.4006048084511261 velocity = <Vector (0.0000, 0.0000, 0.4006)>
frame 25 speed = 0.3498907076119587 velocity = <Vector (0.0000, 0.0000, 0.3499)>
frame 26 speed = 0.30313409275379927 velocity = <Vector (0.0000, 0.0000, 0.3031)>
frame 27 speed = 0.25989567186529 velocity = <Vector (0.0000, 0.0000, 0.2599)>
frame 28 speed = 0.21979808994738081 velocity = <Vector (0.0000, 0.0000, 0.2198)>
frame 29 speed = 0.18251641073621594 velocity = <Vector (0.0000, 0.0000, 0.1825)>
frame 30 speed = 0.14776905415265368 velocity = <Vector (0.0000, 0.0000, 0.1478)>
frame 31 speed = 0.11531056673818194 velocity = <Vector (0.0000, 0.0000, 0.1153)>
frame 32 speed = 0.08492618714236397 velocity = <Vector (0.0000, 0.0000, 0.0849)>
frame 33 speed = 0.05642753543126842 velocity = <Vector (0.0000, 0.0000, 0.0564)>
frame 34 speed = 0.029648051011661188 velocity = <Vector (0.0000, 0.0000, 0.0296)>
frame 35 speed = 0.004440035138811384 velocity = <Vector (0.0000, 0.0000, 0.0044)>
frame 36 speed = 0.019326806042889423 velocity = <Vector (0.0000, 0.0000, -0.0193)>
frame 37 speed = 0.041769969002514604 velocity = <Vector (0.0000, 0.0000, -0.0418)>
frame 38 speed = 0.0629942652418847 velocity = <Vector (0.0000, 0.0000, -0.0630)>
frame 39 speed = 0.08309284741136086 velocity = <Vector (0.0000, 0.0000, -0.0831)>
frame 40 speed = 0.10215073734155207 velocity = <Vector (0.0000, 0.0000, -0.1022)>
frame 41 speed = 0.12024379264552598 velocity = <Vector (0.0000, 0.0000, -0.1202)>
frame 42 speed = 0.13744107480097162 velocity = <Vector (0.0000, 0.0000, -0.1374)>
frame 43 speed = 0.1538053461127377 velocity = <Vector (0.0000, 0.0000, -0.1538)>
frame 44 speed = 0.16939314892522045 velocity = <Vector (0.0000, 0.0000, -0.1694)>
frame 45 speed = 0.1842565017311837 velocity = <Vector (0.0000, 0.0000, -0.1843)>
frame 46 speed = 0.19844265523380794 velocity = <Vector (0.0000, 0.0000, -0.1984)>
frame 47 speed = 0.0665110480737829 velocity = <Vector (0.0000, 0.0000, -0.0665)>
frame 48 speed = 0.13075570077899304 velocity = <Vector (0.0000, 0.0000, 0.1308)>
frame 49 speed = 0.11050409327822751 velocity = <Vector (0.0000, 0.0000, 0.1105)>
be aware that the result maybe more accurate if you slow down your animation.
