Detect object speed?

Question

I have some objects that I need to know how fast they are going. I have a property, "speed," and I would like it to show the object's speed in blender units. For the unit, it doesn't matter that much as long as I can read it. Python or logic would work, but if it's a script I'll have it running at all times. In other words, I'll be using this every logic tic so it needs to be efficient. Thanks.

EDIT: I've figured out how to find velocity on my own, but how would I use that xyz info to find speed?

speed or velocity, not a physicist but I think their slightly different. — ruckus, May 06 '15 at 03:28
@Vince Scalia Probably velocity, although I don't see a difference. — blackhole, May 06 '15 at 12:48
Does this solve it: http://blender.stackexchange.com/questions/29007/a-way-to-get-rate-of-change-in-translation-or-rotation-into-a-shader-node/29184#29184 ? You can call it with scene_update handler instead of frame_change — Jaroslav Jerryno Novotny, May 15 '15 at 06:27
@VinceScalia velocity is the whole vector, speed is just the scalar.. — Jaroslav Jerryno Novotny, May 15 '15 at 06:35

score 5 · Answer 1 · answered May 15 '15 at 16:10

5

Keep track of the objects previous position. Algorithm:

on each logic tick:
     speed_vector = current_position - previous_position
     speed = speed_vector.length()
     previous_position = current_position

answered May 15 '15 at 16:10

beiller

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score 2 · Accepted Answer · edited May 20 '15 at 06:43

2

I have found a nice script from here, and it is the following:

# get the controller
controller = GameLogic.getCurrentController()

# get the game object that the controller is attached to.
obj = controller.owner

# get local (game object) linear velocity
linVelocity = obj.getLinearVelocity(True)

I have modified it for my own scene, and I've also defined speed.

edited May 20 '15 at 06:43

p2or

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answered May 20 '15 at 02:42

blackhole

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Detect object speed?

2 Answers2