MSPhysics 1.0.3 (16 October 2017)

faust07

First impressions of MSPv1.0.0_WIP6:

Great new features and improvements!: Particle recording and export, Escape to stop
exporting, Magnets, Joystick, OnTouch functions ...

I've got my walker model to run. Although I thought first, I can not do it.
The main problem was my inaccurate definition of "Material" in conjunction with "Mass
Control". For example: rubber with a mass of 3 kg, wood with a mass of 10 kg etc.
This worked in version 0.9.9 but after opening with v1.0.0 all former mass values
were displayed in density and the bodies then behaved strangely...
I have now changed all the MSP materials with deviating mass to "Custom" and reset the
display of "by Density" to "by Mass".
It would be good to know the dependence of the strength of the joints on the density
/ mass of the connected body parts. For the walking person, I have to adjust the
triple weight for all parts of the body in order to reduce the wobbling and trembling
to a tolerable level.

An oscillation of previously 60 frames now appears to correspond to a value of 1.0.
Does the oscillation refer to real time or simulation time?
The start rotation direction of the joints changes sometimes? I guess the cause is at
the oscillators starting point at -1.0. But that's ok.

The improper phasing till persists:
The elimination of movement phases of individual bodies is still present. This,
however, seems to be due to the amount of transformed emitters (drops, splashes,
etc.). Without the many emitters, the body movements of my "Little Richie Gear" (I as
a boy with a lantern...) are smooth.

What is the influence of setting "Kinematic" or "Dynamic" to the simulation? Where
can I find the script overview?

Right now, I'm just trying to figure out what the simplest method is to copy a
complex MSPhysics conglomerate like a person (with Curvy Piston and scripts) and let
them act independently.

Anton_S

Hello, Bert,

That's indeed a better model! I made a YouTube video on how to add MSPhysics to it:

Here is the model:
delchrys - gatorator.skp
Regards,
Anton

Anton_S

Hello, Pilou,

There is an onUntouch {|toucher| ...} event for that. Basically when squeezing wall stops touching the stones, you want them to become static, right? To do that, you have to assign this script to the wall(s):

# Triggered when the wall stops touching a body.
onUntouch { |toucher|
  # Ensure that only touchers named, 'stone', are set static.
  next if toucher.group.name != 'stone'
  # Set static
  toucher.static = true
  toucher.set_velocity(0,0,0)
  toucher.set_omega(0,0,0)
}
# Triggered when the wall starts touching a body.
onTouch { |toucher|
  # Ensure that only touchers named, 'stone', are set movable.
  next if toucher.group.name != 'stone'
  # Set toucher 
  toucher.static = false
}

Make sure to name all stones, stone.

However, I think that for cluttering a lot of stones it would be better to manually set them static, say after pressing key, S.
Assign this script to the wall:

onStart {
  @set = false
}
onTick {
  if key('s') == 1 && !@set
    @set = true
    simulation.world.bodies.each { |body|
      if body.group.name == 'stone'
        body.static = true
        body.set_velocity(0,0,0)
        body.set_omega(0,0,0)
      end
    }
  end
}

This, too, requires that all stone objects are assigned a name, stone.

FYI, it's not "Ms Physics" it's "MSPhysics", standing for Math Science and Physics.

Regards,
Anton

Anton_S

Hello, Faust,

@faust07 said:

This worked in version 0.9.9 but after opening with v1.0.0 all former mass values
were displayed in density and the bodies then behaved strangely...

Yes, that was another change I made. I basically renamed the attribute, so it describes the Control by Mass/Density property more accurately. After version 1.0.0, new releases will usually include backup compatibility, but while MSPhysics is still in 0.x.x stage, I don't make changes compatible.

@faust07 said:

It would be good to know the dependence of the strength of the joints on the density
/ mass of the connected body parts. For the walking person, I have to adjust the
triple weight for all parts of the body in order to reduce the wobbling and trembling
to a tolerable level.

In the current versions, joints are the most robust when two linked objects have identical masses. But since linked objects usually don't have identical masses, simply assign realistic mass ratios to objects, and that will usually, too, guarantee strong joint connections. For example, the torso of your robot could have a mass of 1.0 kg, the arm of 0.2 kg, the hand of 0.05 kg, and etc...

@faust07 said:

An oscillation of previously 60 frames now appears to correspond to a value of 1.0.
Does the oscillation refer to real time or simulation time?

Yes, that was changed too. Now the oscillator accepts frequency in seconds of simulation time - number of times to oscillate per simulation second; no longer depends on frame. This change was made to keep the oscillation value persistent when changing the simulation timestep.

@faust07 said:

The start rotation direction of the joints changes sometimes? I guess the cause is at the oscillators starting point at -1.0.

I added another function, called oscillator2, which starts at 0.0 and oscillates from 0.0 to 1.0. See the documentation for details. Also, since 1.0.0 isn't released yet, the documentation is local. To open it, select some group, open MSPhysics UI, activate the Script tab, and select MSPhysics link. From there, click on CommonContext too see all functions you could use as controllers.

@faust07 said:

What is the influence of setting "Kinematic" or "Dynamic" to the simulation? Where
can I find the script overview?

After opening the local documentation, click on Overview tab. There should be a small topic on that.

@faust07 said:

Right now, I'm just trying to figure out what the simplest method is to copy a
complex MSPhysics conglomerate like a person (with Curvy Piston and scripts) and let
them act independently.

This can be done by selecting the entire robot, and enabling the Connect Closest Joints state. Then you can copy it, along with the curvy joint, as many times as you want.

@faust07 said:

The improper phasing till persists:
The elimination of movement phases of individual bodies is still present. This,
however, seems to be due to the amount of transformed emitters (drops, splashes,
etc.). Without the many emitters, the body movements of my "Little Richie Gear" (I as
a boy with a lantern...) are smooth.

Send me a private message with the model so I can see what could be done to improve MSPhysics and/or the model.

Regards,
Anton

pilou

@Anton!
Thx i will test all that!

Can you see the 2 gif animations above?
(because they are on the Su French forum section)

PS Sorry for the MS "Untouching" Physics!
I will remember that for the next time!

Anton_S

@pilou said:

Can you see the 2 gif animations above?
(because they are on the Su French forum section)

Nope, I don't see them. It says I'm unauthorized to view them...

@pilou said:

PS Sorry for the MS "Untouching" Physics!
I will remember that for the next time!

I'm not offended by that in any way. Neither is Ms Physics

pilou

@Anton

By Chri : tricky use of MS Physics!

PS Have you something for "Untouch" objects selected in Ms Physics ?

DAMEUSE2.skp

pilou

Gif animations repaired!
http://sketchucation.com/forums/viewtopic.php?f=323%26amp;t=56852%26amp;start=600#p616669

Sorry for the inconvenience!

faust07

Hi Anton, thank you for the detailed explanations. Much confirms my assumptions. Can not wait for the final version. From the v1.0.0 onwards, it also makes more sense to put models in 3D-Warehouse.
I've sent you a PM with the test model. Perhaps you can find the causes for the jerky movements in complex MSP calculations and give ideas for the improvement of the scripts.

delchrys

Almost ready Anton,
now i only need to get it moving a bit further.
If the two green half circles meet each other and the cyclinder moves further, the whole green circle part should rotate a bit around the origin point. If you know what i mean.
If you look at the following youtube video you should understand what i mean. The first couple of centimeters is needed for closing the green grip halves, the next centimeters are needed to rotate.
regards,
Bert

PS Hope i'm not asking too much
https://www.youtube.com/watch?v=MO2Dy7PM7Gs

Anton_S

Hi, Bert

Here it is:
delchrys - gatorator.skp
Now it rotates along the pipe, like desired.

I also made it compatible with MSPhysics 0.9.9. I assigned all bodies a mass of 1.0 so that the joints are robust. This won't be necessary in the final MSPhysics, version 1.0.0, but that's what required in the current version. I also added grippers to the clutches. The clutches themselves are ignored, but the grippers are collidable. If you enable the MSPhysics Joints layer, you will see the grippers. I also changed the solver model to iterative 64 passes, once again, for a more stable behavior of joints in the current versions of MSPhysics.

Regards,
Anton

delchrys

Hi Anton,

thanks you are the greatest. Now i'm going to figure out all the joints and combinations of groups so i can figure how you do it.
Also i'm adding a other wrench that is holdng the other end of the pipe.
Then i hope it will loosen like i need it to.
Keep you update!!!

delchrys

Anton?
How do you make the guide points?

Anton_S

So, for a circle/arcs, you right click on them and select "Find Center".

delchrys

Ah thanks you didn't know that option. Also downloaded pointtool plugin. Tonight in my nightshift I'm going to draw some more of the model to make a nice overview to show at work. Really loving this msphysics plugin. Possibilities are almost endless

delchrys

Does someone have any advise in rendering for sketchup?
Preferably free??
Like to render some things when i'm done, needs to look good

delchrys

@anton_s said:

So, for a circle/arcs, you right click on them and select "Find Center".

So i kind of remodelled a bit, but can't seem to understand why the pipe continues to rotate even when the grippers are open. It kind of get momentum because of the rotation, how can i stop that. So when the cylinder moves back, the grippers open and let go of the pipe and it stands still.
Made the body static because it will be connected with the other wrench, so that only the gripper head rotates.
Did i do the pipe right by giving him a plane joint and only allow it to rotate???
I don't want it to move in any other direction then rotating caused by the grippers.
Should i accomplish this all by adding friction or is there a simple workaround?
I doesn't have to be Physics Law proof but only look right.

A lot of questions but getting there

PS is ther a plugin for SU2016 to import 2017 files or a simple converter??? I cannot install 2017 at work due to lack of administrative rights

almost final.skp

Anton_S

Hello, Bert,

@delchrys said:

So i kind of remodelled a bit, but can't seem to understand why the pipe continues to rotate even when the grippers are open. It kind of get momentum because of the rotation, how can i stop that. So when the cylinder moves back, the grippers open and let go of the pipe and it stands still.

To fix this, you need reduce linear friction of the Plane joint from 100 to 1. This will the pipe to require less force to move along the plane. Also, setting the angular friction of the Plane joint to 0.01 should prevent the backward rotation of the pipe.

@delchrys said:

Did i do the pipe right by giving him a plane joint and only allow it to rotate???
Either the tool should move or the pipe should move for the grippers to work properly, presumably even in real case scenario. Above, reducing plane linear friction, allows the pipe to move.

@delchrys said:

PS is ther a plugin for SU2016 to import 2017 files or a simple converter??? I cannot install 2017 at work due to lack of administrative rights

Click onFile->Save As and in the Save As Type, choose the desired SU version.

Regards,
Anton

delchrys

Little update

almost final 2016 complete2.skp

alvis

The first impression is good, but for me it is still too difficult to understand some of the physical characteristics of the movement.

Thanks