Colision to be hard

[SilentAssassin21]

hi, ehm i have seen this strange fenomenom that my object 1 is getting stuck into object 2, object 2 is a floor and i see that the visual model is a bit penetrating the floor , so i guess it's something about elasticity of the material or something but i dont know

[SilentAssassin21]

this is a really serious problem, because the objects tends to fall over as it sinks in the floor where the load is most heavy,

when i set the timestep to a smaller number the sinking is decrest but i dont think that's a good idea to do this, because running a 500 fps simulation is nuts

[SilentAssassin21]

Also i would like the state that this is a humanoid robot that has many joints, and the parent is probabbly pushing the foot more down or something into the floor ... man isnt there a trick for this, I mean i bet this is a common problem that could be explained in some FAQ or something how to remove penetration

[JoeJ]

Seems to be the same as my problem: http://newtondynamics.com/forum/viewtopic.php?f=12&t=7586
Maybe it's related to a penetration treshold, so it could help to scale model up - i have not tried that yet.
I'm not sure if the problem is there since i scaled my model down by a factor of 20,
or since the collision system was updated in core 300.

Julio, did you look at my demo?

[Julio Jerez]

can you guys make a youtube, or any other video system, so that I know what I am looking for?

[SilentAssassin21]

okey here is the movie, it's hart to see but focus on the feet going below the surface slowly, the robot is made of hinge joints

[Julio Jerez]

I do not understand the video, I see a while line and a box above that, where is the collsion problem?

[SilentAssassin21]

well as you can see the heals of the robot are sinking into the floor a bit (that is below the surface) , in 0:16 you can see that the foot box is below the surface, partly

[JoeJ]

That's exactly my problem too.
Julio, did you not recieve the download link for my demo via PM?
There you see the same, but contacts with normals and forces visualized, and you can interact with the stuff to test.

[SilentAssassin21]

oh and dont mind the white line that was just for me to debug, that is showing calculation of zero moment point

[Julio Jerez]

Joe I can not run you demo, because I get thsi error when I try to run it,

joeError.png (38.44 KiB) Viewed 4452 times

I do not know how to fix that.

[JoeJ]

I#d bet it's VC 2012 Runtime, but i'm at work now.
Try to download from here:

http://www.microsoft.com/en-us/download/details.aspx?id=30679

[Julio Jerez]

SilentAssassin21,
I see, the error is on the big rectangular box on the floor. when you running this in debug, do you get any warning message?
It is possible for you to send me a test that I can runb to see what it is? I am guessing this is a mal funtion of the calculation of the first simplex on the contact calculation.
That is the most critical part of the collision system, and it happens when two shapes collide face to face, in that case volume of the first simple can be zero, or near zero.
that is not the real problem, the real problem is that when the values are on the vecinity of zero, then rounding float errors affect the algorithm very severelly and the calculation of the first simplex may
not represent a convex tetrahedrum on the convex surface formed by the minkosky difference of two colliding shapes.

There are some warning test that warn when the cituation happens and I fixed all ocurrances in my test demos,
but there may be more cases where the problem happens between the criteria that test if the first simplex is good or not, it is hard to debug without a demo.

If you can send me a test demo, I can add the fix for that.

[Julio Jerez]

Joe I do have those libraries

I think this is a path problem, but I can not figure out how to make it run, I copy the forder here
C:\dev\pengII\pengII\Release\pengII.exe

is that the righ path?

Is this Msvcr110.dll a visual studion 2012 runtime library? hwo ddid you get that? if we are usin the same version of visual studio?

[SilentAssassin21]

Oki I will send it to you when i get home from work, thanks very much for the effort, by the way where should i post it?