Thread: Walking with physics

1. Originally Posted by galok
this is so close, i almost did it guys
Nice work.
I tried making a walking simulation myself some time ago but failed miserably :-) Main problem was that I really lacked even basic knowledge on how humans do balance themselves. If I would have tried that today I would definitely have better chances of succeeding.

2. i guess this is relatively stable.
here is source (Delphi XE7) and build: box2d_test.zip

Originally Posted by SilverWarior
Nice work.
I tried making a walking simulation myself some time ago but failed miserably :-) Main problem was that I really lacked even basic knowledge on how humans do balance themselves. If I would have tried that today I would definitely have better chances of succeeding.
Thank you, it wasn't easy for me either, you can look at my source if you want

3. Originally Posted by galok
Thank you, it wasn't easy for me either, you can look at my source if you want
Maybe some other time. I already have to many unfinished projects of mine.

4. i'm tried as hard as i can translate simulation parameters to box2d, i translated object sizes, mass, inertia and positions of joints, after this i created fixed step loop procedure (200 iterations with Dt = 0.00005) and run simulations in zero gravity to step 33, but results is still far from good, i think i'm mistaken somewhere...

and values of variables are different
(torque hash, root velocity, relative angles)

Simbicon:
--- 33 ---

384,45

0,47 -0,09

-1,80
-0,23
-0,70
-0,01
-30,86
1,43
-0,01

Box2D:
--- 33 ---

287,05

0,40 -0,07

-1,48
0,10
0,79
0,46
-31,42
14,11
9,78

5. The cause might be in different floating point precision between your and original program.

6. Originally Posted by SilverWarior
The cause might be in different floating point precision between your and original program.
I tried to do less iteration in order to decrease precision error, 20 iterations with 0.0005 Dt give same results. simbicon use single precision float for calculations. i'm not sure, but it seems box2D use single precision float as well.

i tweak simbicon a little and the only way i got something that looks like what i've seen in box2d is when i manually decrease left shin torque by 10 times, don't know what this mean

7. oops, i found out a problem, angular velocity should be also relative to parent angular velocity, this doesn't seemed obvious to me... now it works perfectly

Simbicon:
--- 106 ---

37969,48

0,08 0,00

-2,49

34,48
-89,00
12,03

-60,76
-18,80
14,67

box2D:
--- 106 ---

37983,68

0,08 0,00

-2,47

34,48
-88,98
12,01

-60,60
-18,82
14,64

8. scaling code is correct now
box2d_test_3.zip

9. Originally Posted by galok
Really impressive, but hilarious too.

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