MSPhysics tests and questions

Anton_S

There were a few issues.

In new version, onTouch is triggered only one time, whenever there is a contact between bodies. In your script you tried to use the onTouch event as a repetitive event for generating trailing waves. It did work, as a bug, in version 0.9.9 but not anymore.

Another thing is setting emitted bodies non-collidable. Setting the original bodies non-collidable won't make the emitted body non-collidable. You must appply such state explicitly to the emitted body:


body = simulation.emit_body(...)
body.collidable = false

I fixed all these issues and also made rain droplets be independent of touch event.

Faust's Whale.skp

faust07

Hi Anton, once again thank you for the quick reply.
This is, of course, an interesting approach and for me something new to explore again.

A touch function as a repetitive event for generating something would be great. I think it was a good bug and you should bring it back as separate option. if it is possible...

One problem in the new solution is, that after about 700 frames the lifetime of some emitted objects doesn't end.

Anton_S

Hmm... I think something is wrong in code or with MSPhysics. Try changing the rain dproplet's code to this:

onStart {
  @instances = {}
}

onTick {
  dir = this.group.transformation.zaxis
  dir.length = this.mass
  point = this.get_position + Geom;;Vector3d.new((rand()-0.5)*1000, (rand()-0.5)*1000, (rand()-0.5)*10)
  tra = Geom;;Transformation.new(point)
  rain = simulation.emit_body(this, tra, dir, 5)
  rain.collidable = false
  @instances[rain] = true
  @instances.reject! { |k,v|
    next true unless k.valid?
    point = k.get_position(0)
    if point.z < 0
      #k.destroy(true)
      posineu = Geom;;Point3d.new(point.x, point.y, 5)
      tra = Geom;;Transformation.new(posineu)
      body = simulation.emit_body(@@splash2, tra, @@dir, 0.25)
      body.collidable = false
      if frame % 3 == 0
        posineu = Geom;;Point3d.new(point.x, point.y, -2)
        tra = Geom;;Transformation.new(posineu)
        body = simulation.emit_body(@@bubble2, tra, @@dir, 0.2)
        body.collidable = false
      end
      next true
    end
    false
  }
}

Aside from that, you can use onTouching event for repetitive action, but it only yields toucher parameter and doesn't provide touch position.

faust07

Without the k.destroy function it works better now. Thanks, Anton.
Controlling the disappearance of the drops by setting the lifetime is sufficient...
I have meanwhile found a way to make the marine life's bow wave smooth on the surface of the water, even if it slopes sideways.
More complicated is it, when objects are jumping out of the water, when diving or with falling ice floes causing the appropriate waves and splashes, which was very easy with the good old V0.9.9 bug function.
The gif-example is old, but shows what I mean.
Witch toucher parameters can I use from an onTouching event to get recurring waves and splashes during prolonged movement of objects in the water?

Anton_S

You can rely on MSPhysics::Body.#contacts function. Add this code to an iceberg to see the effect:

onTick {
  if this.get_velocity.length > 1.0 && frame % 10 == 0
    this.contacts(true).each { |contact|
      body = simulation.emit_body(@@splash4, contact.point, @@dir, 0.4)
      body.collidable = false
    }
  end
}

faust07

The script works in this form good for a few objects. The falling pieces of an iceberg touch each other and produce emitting objects everywhere in the air in mass. SketchUp crashes then ... It would be good if I could use instead of .each a certain surface for the contact. Another problem is that all splashes are created simultaneously. Therefore a script for a random time point of emitting would be very helpful. I'll try this...

faust07

After I have tried several things and have not come to any satisfactory result, I have a suggestion:
It would be great to have a kind of "Penetration Joint" or function (onPenetration):
to connect it to one or more noncollidable objects (or faces).
The properties of objects that penetrate this noncollidable object are to be evaluated continuously:
name, mass, velocity, position of the touch/penetration, direction of movement, etc..
In other words, please bring back the old onTouch bug as an independent function!

faust07

I finally found a satisfactory solution for my imitated water fun in MSPhysics v1.0.2:
A combination of a surface with onTouch function (water surface) and an evaluation of velocity.lenght (onTouching event) and contact.points of in the area of this surface moving objects.
Anton, thank you for the examples, hints and help!

faust07

Hi Anton,
I want to bring more variation into the particles of the orca's breathing air. My intended scaling function does not show any reaction. What can be the cause? Can't scripted emitted objects not be scaled during simulation?


for i in 1..20 do
  tra = this.group.transformation
  dir_zsf = tra.zaxis
  dir_zsf.length = 290 + rand(100)
  fount_p = Geom;;Point3d.new(0.0 + rand(-5..5), 2.9.m + rand(20), 0.5.m + rand(15)) # y-pos of fountain
  point = fount_p.transform(tra)
  transl = Geom;;Transformation.new(point)
  scalin = Geom;;Transformation.scaling point, rand(1..5)     
  transf = scalin * transl
  if point.z > 0.1.m
    body = simulation.emit_body(@@splashF, transf, dir_zsf, 0.2)
    body.collidable = false
  end
end

faust07

The next step is to find a solution to bridge the gaps that arise between the moving parts of the objects at the pivot points.
I think of flexible triangular or square surfaces, which I can clamp between the boundary lines of the moving parts. For this I have to immerse deeper into the Ruby programming of SketchUp geometry ...
If someone from the experts has ideas, I would be very happy.

and how it looks like rendered with indigo RT

faust07

Hello Anton, here an other little question:
When I let run "Replay" with active hidden geometry all emitted objects remain in there last position still after there lifetime. Is this normal? Could that explain why Twilight takes longer and longer to render the images during the simulation?

aldoz8

Hi, I hope I am in the right place to put my question..

I am developing a quadruped robot:
Youtube Video

So I am using SketchUP make 2017 + MSPhysics to test different settings of my robot and different scenarios :
Youtube Video

Just cool! but I have a little problem:
In Sketchup I am using 8 servos, 2 for each legs and I get (as you can see in the second video) 8 MSPhysics sliders to move my 8 servos.
Ok, but I would to have another slider that let me to move, for example, servos 3,4 and 5.
So I would to obtain my actual 8 sliders + 1 new sliders that move servos 3,4 and 5.
Obviously I will be able to move servo 3,4 and 5 using both the old 3,4&5 sliders and the new one slider too!
So I will obtain :
SLIDER 1 = servo 1
SLIDER 2 = servo 2
SLIDER 3 = servo 3
SLIDER 4 = servo 4
SLIDER 5 = servo 5
SLIDER 6 = servo 6
SLIDER 7 = servo 7
SLIDER 8 = servo 8
SLIDER 9 = servo 3, 4, 5

How to do that?
Thank you all in advance!

ecati

aldoz8
If you can not find a solution, do you share the skp file?

Jens3D

I downloaded MS Physics plugin after seeing a demo from Justin's SketchUpEssentials. Looks really cool, but is it really compatible with Mac? It says it is, but following the tutorials on Youtube, all the setup modes seem to function, but when it comes to implementation, the model disappears, and a counter on the bottom left hand of the screen counts ‘Frame’, Time and FPS. Goes on forever! Is this normal?

Box, on the SketchUp Forum looked at the model for me on a PC, and then had similar issues, so suggested that this is not necessarily a Mac issue.

I am setting up a mobile (to hang above a baby's cot) with rotating discs balanced on a simple rod. Each disc then has to be able to swivel on its vertical axis, each group would then too, and then including the main arm holding all the groups has to be able to swivel on its axis.

Can Anybody offer some advice.

Thanks
Jens

faust07

Judging from the description, objects outside the window seem to fall into the bottomless state and cause the SketchUp clipping problem. All groups or components that should not be simulated should be set to "Ignore" or "Static". This can be done in the MSP user interface or in the MSP context menu. A sample SUp model is always very helpful for more precise assessments.

faust07

@ aldoz8:
There is no easy solution for this after my first tests. Each slider can directly control only one joint (and several identical copies of the joint) at a time. It is possible to use scripts to query the input values from a slider and pass them on to the required other joints. Unfortunately, I don't have time for an example. Sorry!

ecati

This is a message sent by mistake. It needs to be deleted. I did not delete it. Sorry.

tecnozati

Hello everyone, to see if a charitable soul can help me out.
Using MSPhysics script I want to get:
1 know the position of a servo join
2 move the servo without using “get_var ()” as controller

I wish to animate a mechanism with scripting, I would greatly appreciate code examples (I find it almost impossible to find them)
Greetings and many thanks

faust07

There is a link to the Scripting Documentation in the first post of Anton_S regarding his MSPhysics plugin: https://sketchucation.com/forums/viewtopic.php?f=323&t=56852

Anton_S

tecnozati,

Yeah, the docs do not have enough coding examples. But I intended to fix that someday.

To get the position of a servo joint from a script field, you will first need to know the name/id of the joint, which is displayed in UI when you select the joint. Then you can write the following code:


onStart {
  @j = simulation.find_joint_by_name("569422")
}

onTick {
  # Set desired angle
  if (key(' ') == 1) 
    @j.controller = 100.degrees
  else
    @j.controller = 0
  end
  
  # Get current angle
  simulation.log_line @j.cur_angle.radians
}

You can refer to servo docs for more functionality: https://www.rubydoc.info/github/AntonSynytsia/MSPhysics/MSPhysics/Servo

Anton