Big problems with physics.

All right, I found this problem with Bullet physics, I don’t know what’s causing it, might be my settings. Add a cube. Scale it on one axis, and skew it so it will fall when you start the game. Then make it actor, dynamic, rigid body, bounds:box. Set the engine to bullet. Duplicate this object a bunch.
Now add some other primitive (I used a cube) and set it to Actor, but not dynamic. Give it simple DLoc controls for forward, backward, left right, (any set up so you can control it.) Give it proper bounds, box, sphere, whatever matches your object. Now if you move it into the pile of dynamic boxes, it OBVIOUSLY influences them, but not at all properly, it’s all messed up.

Is it just me?

what exactly do you mean not properly can u post a file maybe?

i just tried it on a small scale 3 objects and the controled one

and it pushes them like normal (or as normal as it will get )

It’s because you’re using DLoc. DLoc in the old sumo physics and I’m guessing also in the new bullet physics does the same thing. It moves your object to one position by incrementing to it. DLoc is not desirable for real physics. DLoc would have you go through walls, etc and probably in this case through cubes. Use velocity and see if you get a proper affect.

Jason Lin

Thanks. But here’s what I don’t get. Gravity doesn’t affect objects that are using LinV! I guess I’ll have to make a ground sensor.

linV just sets the linear velocity. so it overwrites the any gravity effect.
Apply impulse is another way of interaction.

However, if you want character control, most games don’t use a dynamic/rigidbody they have a special solution, kind of similar to having a special solution for vehicles (which is in Bullet right now).
There will be a special character control solution in Bullet,when its done.


Can’t wait to see the special character control,

even if any character in any of my old demos are just cubes or spheres:)

I hope to see that and compounds in a future 2.43 preview #

Yes using dynamic only character control in Bullet seems a bit awkward. I do think this special solution will fix that.

Thanks Erwin! I need to figure a system for char. control until then, anyway. It’ll probably involve empties… oh well.