SketchyPhysics 3x June 27 version.

CPhillips · 28 Jun 2009, 06:16

Here is a new Experimental version. Its major feature is the new scripting system so it is primarily for users who are comfortable with script. It is work in progress code and possibly very buggy. You guys let me know.

Because this is not even an alpha I am putting a notice not to upload to 3dwarehouse. But PLEASE post models to these forums. I need to know how you are using the scripts so I can figure out how they will ultimately turn out.

Documentation for this release is going to take a while. I will start with examples in the next post.

Chris

http://sketchyphysics2.googlecode.com/files/SetupSketchyPhysics3x-Jun27.exe
No Mac version yet but there will be soon.

CPhillips · 28 Jun 2009, 06:33

Here is an example using the new scripting system. It uses the "ontouch" event to create joints between objects. The wheels on the car will connect with a hinge the first thing they touch, in this case the box. The spheres will connect with a ball joint everything they are touching the first frame. That allows them to connect to anything they are touching in the chain.

The nice thing about joints made this way is that you can copy them and they still work as expected.

SelfConnectingJoints.skp

CPhillips · 28 Jun 2009, 06:38

This example adjusts linearDamp to make bodies act like they are in space. Also shows that objects can be started in motion.

orbit4.skp

CPhillips · 28 Jun 2009, 06:43

Simple breaking objects. The breaking interface is really a work in progress. Sometimes objects breaking can cause Sketchup to crash.

Break1.skp

Wacov · 28 Jun 2009, 08:43

In the ontouch event, is the speed the speed of the collider at impact... and pos the point of impact?

And thanks for those demos!

Here's my first proper model with it, copyable ragdolls! You can't freeze them normally, but you could probably set them to freeze on frame 1, after the joints have connected.

Copyable ragdoll.skp

Wacov · 28 Jun 2009, 20:59

Chris, how DO you freeze objects in script? Has that been added yet? I've tried frozen=true and frozen(1), but no luck.

Physicsguy1 · 28 Jun 2009, 22:31

Since this version is unstable, it would be best if you created a method that stops the simulation, after an amount of time, if something strange happens, or the ismulation gets laggy(breaking feature).

CPhillips · 29 Jun 2009, 00:32

@wacov said:

In the ontouch event, is the speed the speed of the collider at impact... and pos the point of impact?

Yes.

CPhillips · 29 Jun 2009, 00:32

@wacov said:

Chris, how DO you freeze objects in script? Has that been added yet? I've tried frozen=true and frozen(1), but no luck.

Doesn't look like I have hooked that up yet.

CPhillips · 29 Jun 2009, 00:36

@unknownuser said:

Since this version is unstable, it would be best if you created a method that stops the simulation, after an amount of time, if something strange happens, or the ismulation gets laggy(breaking feature).

There isn't a "magic bullet" for that. I need to find all the different ways it can break and then tackle them one at a time.

Post any code you find that breaks the sim and I'll put the right error checking in.

Wacov · 29 Jun 2009, 01:19

Pretty nice cloth demo. Once again, totally copyable! I love the scripted joints

Copyable cloth.skp

CPhillips · 29 Jun 2009, 01:59

Nice!

Physicsguy1 · 29 Jun 2009, 03:03

That's a nice representation of cloth, Wacov!

Wacov · 29 Jun 2009, 10:54

Thanks guys! One thing I'm finding with the cloth is it tends to collide with itself. That seriously slows stuff down, and it's not really neccessary for a semi-realistic simulation. Can we have object-specific collision detection? So, give the choice to either collide with everything, collide with everything except '...', or collide with nothing but '...'. Keep it pretty intuitive, so using a string finds objects of that name, a var for specific objects, and let us put them into an array if needed.

So, on the cloth, I'd name all the bars the same, and tell them to collide with everything except each other. You might also be able to make a crude fluid flow effect by creating spheres that only collide with the static mesh.

phy · 29 Jun 2009, 13:39

I love the new Script field and script but I was wondering is there any way you can control a scripted joint with a slider or key.

JaViXP · 29 Jun 2009, 16:11

Just a little test. Hit Play and see what happens

Download this file

Physicsguy1 · 29 Jun 2009, 21:29

YES!! The simulation finally registers in-simulation created objects!

CPhillips · 29 Jun 2009, 23:03

@wacov said:

Thanks guys! One thing I'm finding with the cloth is it tends to collide with itself. That seriously slows stuff down, and it's not really neccessary for a semi-realistic simulation. Can we have object-specific collision detection? So, give the choice to either collide with everything, collide with everything except '...', or collide with nothing but '...'. Keep it pretty intuitive, so using a string finds objects of that name, a var for specific objects, and let us put them into an array if needed.

So, on the cloth, I'd name all the bars the same, and tell them to collide with everything except each other. You might also be able to make a crude fluid flow effect by creating spheres that only collide with the static mesh.

In the physics engine you would need materials to do that. So don't expect it until SPIV.

One thing you could do that might speed things up is to change the connect script to something like this.


ontouch{|t,s,p|
   connect(t,"ball") if frame==1

    #empty the ontouch event after the first frame.
    #this will ensure that ontouch isnt called again.
   ontouch{} if frame>1 
}

CPhillips · 29 Jun 2009, 23:04

@phy said:

I love the new Script field and script but I was wondering is there any way you can control a scripted joint with a slider or key.

Not yet. But I will do that next.

CPhillips · 29 Jun 2009, 23:05

JaViXP it will work better if you change the onend to this:

onend{
   group.erase!
}