Help with robot arm and stacking cubes

Hi all,

First excuse me for my bad english. Im new to this forum and also pretty new to blender. But i am already addicted to it. I have actually two questions. I searched all the forums and tutorials but i couldnt find the answer. The first one is about stacking objects. if i stack a bunch of cubes and start the game engine they start shaking, no matter what settings i try. i tried the settings in the material panel but with no luck. with the no sleeping function off the boxes stop moving after a while but the transition between moving and sleeping is very ugly. so is there a way to get a stack of boxes still with no sleeping turned on??

second question is about an idea i have to make a robot arm that can pick up objects. I want to be able to move different arm segments of a robotic arm with different joystick axes. I tried it with the servo funtion but i had really no clue how to do it. what is the best way to do it if it is actually possible?

Thanks in advance

hello and welcome to this blender forum!
Just a little while ago, I too was conducting research on how to stack objects and move them with a robotic arm.

First, let me tell you that i am new to the blender game engine. My strength is modeling and texturing in blender and a few other 3D apps but lately, I’m focusing mostly on the game engine because i find it fascinating.

The reason why your cubes are shaking is because you have not set “Bounds” to box. Another thing to consider is the “Radius” setting. Default is 1.00

To be able to set a radius, your cubes need to be “Actors” with Dynamic & RigidBody enabled.
Dynamic is necessary so that they can be stacked and RigidBody will make them bounce and rotate should the robotic arm drop them.
I’d make you a little demo blend but i had surgery this afternoon and don’t feel well at the moment.

Hopefully someone could help you with that and add to my suggestions.

Good luck :slight_smile:

After reading your post again, I’d like to add a few things.
The program i hope to create is based on objects being moved and all is controlled by a joystick. My objects are all actors and the robotic arm is not an actor - i find this combination works best for my needs but am still experimenting …

Thanks for the reply onemanblend. Hope you are feeling better soon. The settings you mentioned for the stacking problem i allready had them. Changing the radius settings doesnt seem to change very much. I tried every bound setting but the problem stays.
Here is a link to a very simple blend file with a stack of cubes with no sleeping turned on.
The staking is subtile but i hope there is a way to stop it.

I hope someone has some sugestions for the robot arm i’m trying to make.

I’d just like to add that if you use bounds on your object, the radius has no effect on it.

Myself have had no experience with joysicks in blender. But if you take a look in the logic bricks, one of the sensor is “joysicks”. From there it allows you to pick an axis. Then add an and controller and rotation acuator (implying that you need to rotate the arm with the joystick).

Correct me if I’m wrong but this is my guess

Hi again,
i’ve downloaded your blend and adjusted a few settings that should have fixed the problem … but for some reason i could not get the cubes stable with “NoSleeping” enabled.
I remember seeing an animation where a car drives into a large wall made of countless bricks so there must be a way of doing this.
Settings i’ve tried:
Under Material Dyn (for each cube) i’ve played with various low/high values
Set the Mass on all cubes to 1
Upped the damping and rot damping to 0.95 for each cube
And most of all, eliminated the gap between the cubes which i did actually first. This should have made a huge difference.

You see, when i encounter a problem like this, I change the plan to enable blender to handle my scenes.
The reason i’m mentioning that is that in my game engine project a robotic arm has to pick up and place objects but the objects are all on a shelf (something like a shlef).
I think someone can still help you with your project but if not, I would simply rethink the setup a bit?
Sorry to be of not more help. Btw, I had surgery last Friday and it’s no fun to use my laptop for blender work in good days, not to mention the delirious ones.
I’ll keep an eye on this and if something gives, I’ll post you a blend.

Good luck and don’t give up!

Sorry, something else just popped into my mind … once you are working on the robot arm, use very small values when squeezing the objects that need to be picked up or it will not work. Lately i just use ipo curves in combination with logic bricks to play tiny parts of animation which works best for me.
One example is a hydraulic arm that had to extend in three stages … it never looked good until i used actual animations and called the movement via ipo … ok, time for another Tylenol 3


for your robot arm i have an idea…

what you could do it make each movable segment into a seperate mesh and perant them progressivly, so the grabber is parented to the one above and so on so forth. also for the motion use a simple motion actuator (make sure its set to local!!)
i hope you understand, i would make a demo but i gotta go in a minute