adding physics objects question[corrected]

pildanovak · Post by **pildanovak** » Mon Jun 19, 2006 12:13 pm

I'd like to ask if the bug/requested feature about adding dynamics objects as children of static objects is planed to be corrected in 2.42, since I'd like to know this for the game contest. It would be really useful for adding stacks of objects in the level dynamically, and adding sonstrained structures is impossible by now, and would be very complicated to set up manually in python.
i've done another bug demo with added rope bridge. run it and press SPACE. the constraining scripts run without any bugs, but the constraints are not set up, and also the file crashes, if you run it press SPACE, change something(almost anything, script, physics properties of any object...), run it again, press SPACE, crash.

http://plant.ffa.vutbr.cz/~novak/dwnflz ... idge.blend

pildanovak · Post by **pildanovak** » Fri Jun 23, 2006 2:22 pm

sorry for bugging with the same bug again... I made another, I hope more komplex example of the behaviour of added object structures.
use ABCD to explore various cases of added structures, and E to try more with adding some other objects. I think the transform of the objects gets multiplied in some strange way. shows that something with the transform of the objects is wrong... I think I'll post this also to bug tracker if i hadn't already

http://plant.ffa.vutbr.cz/~novak/dwnflz ... p2p2.blend

I think if the physics objects as children can not get added correctly, maybe this feature should be blocked completely by now?

also shows how added constraints work now. Probably if made completely over python, could work now(I haven't tried yet) but in this combination with logic bricks - linkage doesn't work...
Anyway thanks a lot for the fix of phys id, if i have time I'll try to pythonize that thing completely...

Erwin Coumans · Post by **Erwin Coumans** » Fri Jun 23, 2006 3:36 pm

Can you briefly (in 1 or 2 lines) describe what you want to achieve?

Do you want to 'add' a bridge/rope with constraints?

pildanovak · Post by **pildanovak** » Fri Jun 23, 2006 4:36 pm

yes.
edited - yet simpler - adding physics objects in a group - car with wheels, pile of boxes(unconstrained), rope. Please look at the files, they are simple to get.

Original
{But wanted to do it at once since if adding and constraining all trough python is hard = for a bridge/pile of something you would have to record all positions of objects, and know exactly constraining points and hardcode them. Better add them all in a preedited group, which is possible by adding some common parent(an empty) of all the parts. please look at the files provided, i really can not describe better.}

Erwin Coumans · Post by **Erwin Coumans** » Fri Jun 23, 2006 5:11 pm

rigidbodies/dynamics objects should never be a child in any case.

For now, python is the only way.
Hopefully we can introduce 'grouping' in the future, when we introduce 'physics constraints' in Blender user interface.

pildanovak · Post by **pildanovak** » Fri Jun 23, 2006 5:30 pm

I agree fully, that's what i proposed. Maybe the groups introduced by Orange could be used for a special version of add object actuator. But now adding physics obects as children is possible, which is confusing, because it works by a half.

Erwin Coumans · Post by **Erwin Coumans** » Fri Jun 23, 2006 8:03 pm

The Orange groups is a good suggestion. Also when rigid body constraints are introduced, the whole connected group can be added at once.

But now adding physics obects as children is possible

It is an undocumented feature, I didn't even know it was possible.
The nature of Blender game engine leaves a lot of freedom, and not all paths are closed for the user.

Instead of disabling the feature, it is documented in the Physics Tips:

http://www.continuousphysics.com/mediaw ... ysics_Tips

Thanks,
Erwin