SketchyPhysics3 FAQ.

CPhillips

I can't believe I havent done this sooner. Most of the questions on this forum have been asked and answered a dozen times.

I am going to edit this sticky post to keep it up to date based on this thread and questions in other posts.

Right now this is just an outline. And I need your HELP build this FAQ! Post as a follow up either a question or better yet a question AND the answer.

Sections
[*]What is SketchyPhysics
Sketchyphysics is a plugin for Google SketchUp, which runs simulations based on real-world object physics. This means that, during the simulation, Newtonian physics laws are applied to grouped objects, with runtime user interactivity added through an on-screen object dragging stystem, using the mouse to pull objects around. Joysticks, and limited joypad button/keyboard input is supported to control a selection of joints and settings applicable to grouped objects, including self-replicating emitters, thruster settings, magnets, and more. Limited Ruby script use is also supported for more advanced actions; for examples of Sketchyphysics in action, please install Sketchyphysics on your PC/Mac, and search for 'Sketchyphysics' on the Google 3D warehouse.

[*]Where can I get the latest version
The latest version will always be in a sticky post at the top of this forum:
http://www.sketchucation.com/forums/scf/viewforum.php?f=61

[*]What are the different versions
Sketchyphysics is occasionally updated, with new features and bug fixes addded each time. The general version history, and future, are as follows;

Sketchyphysics
Earliest version of Sketchyphysics, with simple joints that did not allow true runtime control. User interaction was limited to just pulling objects around the screen, and the physical size of the simulation was limited, although the physics were accurate.

Sketchyphysics 2.0b1
The popular second release never actually left Beta phase; numerous bug fixes, massive world sizes and joint controllers were added, along with a selection of new joints and joystick support. Simulation-controlled camera was also supported, and a wide variety of games sprung up on the 3D warehouse.

Sketchyphsyics 3
SP3, currently at release candidate one, added an almost unlimited world size. Magnet, thruster and emitter settings were added, along with a corresponding magnetic option, as well as the option to add an infinite bouyancy plane to the model. Joypad button and keyboard support has been added through joystick emulation, and ruby script support (With global variables) for control of the simulation has brought unlimited possibilities for real-time interactivity. A new, breakable fixed joint was also added, for connecting thrusters and emitters to parent objects, and for breakable environments/objects. A recording and exporting option was also added, for rendering the simulation.

Sketchyphysics 3 Experimental (SP3 X)
More advanced scripting, with collision events and triggers, and limited sound effects are all confirmed for this experimental version. Upon release, it should be noted that models made using it will most likely not work with future versions.

SPIV
This highly anticipated, totally re-written future version will make connecting objects and joints a breeze, with complex models that currently take hours to build sped up to mere minutes. A higher degree of interactivity and easier to use interface will allow modellers to easily create a physics environment, without the hassle of a joint connector tool, and with no problems copying and pasting joints.

When will version X be released
Unfortunately, due the authors erratic schedule release dates are seldom hit. Go ahead and ask, but expect vague answers. Currently the next versions planned are SP3.0 and SP3x. Either could be in a few days or weeks.

How to install and start using SketchyPhysics...

To use SketchyPhysics, you first need to install the latest Google SketchUp 3D designer. SketchyPhysics is not a "stand alone" program, it is a plugin for SketchUp, therefore, requiring SketchUp to run. You can download the free or the Pro version of SketchUp. Use the following URL to view the current available version...
http://sketchup.google.com/
Select the version for your OS, run it, and follow the on screen prompts.

Now that you have installed SketchUp, use the following link to view the latest SketchyPhysics downloads...
http://code.google.com/p/sketchyphysics2/downloads/list?can=1&q=&sort=-uploaded&colspec=Filename%20Summary%20Uploaded%20Size%20DownloadCount
Again, run it, and follow the on screen prompts. It will install itself in the SketchUp Plugins folder.

After you have installed both SketchUp and SketchyPhysics, run SketchUp and go to the "View/Toolbars" menu. You will see some new menu items "Sketchy...". If there are no checkmark next to them, click them to add one. This will make the on-screen toolbar visible for easy access. Move the toolbars as you see fit. SketchyPhysics will also be listed in the "Plugins" menu, and in the right click context menu of objects.

To run a SketchyPhysics model, use the following link to search the Google 3D warehouse for SketchyPhysics models...
http://sketchup.google.com/3dwarehouse/search?q=SketchyPhysics&styp=m&scoring=d

Once the model is loaded in your SketchUp, click on the "Play" simulation button. Some model may require you to use your keyboard/mouse/joystick to manipulate the simulation, as in a car game for example. Note that when running a simulation, you can not perform any modifications to the model. Anything that you move while the simulation is running will react as in real life. Click the "Play" button again to Pause the simulation, or the "Reset" button to stop it all together and then you can edit the 3D model and make changes.

What do all the buttons and menus do?

The Inspector (UI)
Your general-purpose config window for Sketchyphysics joints and bodies. When the UI is open, and an object is selected, all primitive shapes within are displayed. Here you can set thruster, magnet and emitter settings for the selected body, including entering formulas and Ruby script... any internal or connected joints are also shown, and you can click on one to configure its parameters and controller, which, again, can be a formula. State properties for any object can also be changed here, which will affect how it behaves... for example, a body set to 'frozen' will be immobile until either it is clicked, or an unfrozen object collides with it. 'Ignore' sets the object to be totally ignored by the simulation, immobile and untouchable, 'No collision' stops an object colliding with other objects, and 'Static' will totally immobilise the object, while still allowing other objects to impact it.

Right-click menus
When you right-click on an object, you will see options for Sketchyphysics. Here, you can change states and shapes (which can applied to a number of objects at once), and 'debug' an object, to make it show its Collision geometry (Its physical shape) when the simulation plays.

The toolbars
The play/pause button, which runs the simulation, the joint connector tool, and the UI button are all located on the Sketchyphysics toolbar. Also included is the shapes toolbar, which you can use to quickly make physics shapes, the joints toolbar, which contains all of the working joints available to place in your model, and the Sketchy replay toolbar, with which you can record your simulation.

Plugins/Sketchyphysics
This contains the windows which you use to govern global settings for the physics in your model, like gravity, density and bouyancy settings. You can also choose to run Sketchyphysics 2 rather than 3, to run models using the depreciated 'magnet joint' and any other SP2 models that won't run properly in SP3.

The Sketchy Replay section under plugins enables you to export your recorded simulations, as either JPG, PNG or .skp files.

[]How do I make a simple objects
[]How can I make more complex objects

Use of the joints
Commons

You can create joints trought the SketchyPhysicsJoint toolbar. If you can't see it, go to View/Toolbars and click on the corresponding button.
2.To select a joint, right-click on the corresponding button.
3.Click one time in your model to set the joint center. Click a second time to select the joint axe.
To link a joint to an object (group) select the "Joint connector" tool, click on the joint, then Ctrl+click the object. To check if the two objects are linked, click any of them. You will see a yellow cage around the joint and a green one around the object.
Object can be linked to more than one joint, and vice versa. There is a bug with connecting muliple objects to a "controlled" joint.
Joint can be grouped to objects in order to make them movable. Joints grouped with objects became new objects and can be linked to another joint.
You can add values to the joint's variables, like maximum and minimum. This is another subject, but remember that angular values are expressed in degrees, and linear values in inches.

Types of joints

Hinge: Object linked to this joint can spin around his center.
Servo: Basically a controlled hinge, suitable to control arms, doors and similar things.
Motor: Another controlled hinge, build to control wheels- only maximum speed is available.
Slider: Object linked to this joint can move linearly between the maximum and minimum.
Piston: The controlled version of the Slider joint.
Gyro (for gyroscope):Object linked to this joint will have the corrispondent axe locked.
7.Fixed: This joint was made to fix an object to another in order to remedy some problems that comes with grouping special objects(emitters, thrusters) to other objects. It is also useful for his "breakingForce" variable- if something hits the object with enough force, the link breaks up.
End part 1

Use of the joints 2
Other types of joints
These types of joints are not used as often as the others. They are considered "legacy" joints by the physics engine. The are less full featured than some of the other joints and have fewer options.

Corkscrew: Object linked to this joint can spin around his axe and move between maximum and minimum.
Spring: Object linked to this joint can move linearly along his axe. The spring joint will try to bring back them to the first position.
Ball: Object linked to this joint can rotate freely around the joint. The object axe points to the joint.
Universal: Object linked to this joint can rotate almost freely around the joint. Unlike the Ball one, the Universal joint won't allow the object to rotate around his axe. See those images to understand the concept:

Universal Joint

Ball Joint

How do thrusters, magnets and emitters work?

Thrusters, magnets and emitters are all settings you can apply to any physics body in your model, using the UI; the thruster option will propel the object with a constant force along its Y (Blue) axis (However, this can be changed using the formula box). The power is user defined, and is dynamic, able to accept formulas and Ruby Script; a setting of 0 is off, so you can use something like joybutton("a")*1000 for runtime control.

Magnets affect any 'magnetic' objects nearby, with a force that can be defined much like that of the thruster. In this case, a negative value will push magnetic objects away, and, again, 0 is off. The setting for 'magnetic' can also be found in the UI; note that it's possible to turn both settings on for a single object.

Emitters create copies of themselves, which can be created with momentum along their Y axis. The lifetime setting dictates how many frames the emitted objects will remain; in this case, a setting of 0 will cause them to remain for the duration of the simulation. Strength is the momentum of the object when it is created, and rate is the number of frames between emissions; a setting of 0 for either of these will turn it off. These are dynamic, so you can turn emitters on and off, change their power and the rate of fire all during the simulation, using a formula or script. Note that complex 'objects' like a vehicle made up of many jointed groups cannot be emitted. Emitted items also lose a variety of settings applied to the parent object, such as whether it's hidden, any state changes, and any Thruster, Magnet or Emitter settings.

[]How do formulas work
[]Trouble shooting
[]Known bugs
[]??

CPhillips

Is it ok with everyone if I erase the original post when something is accepted into the FAQ?

I want to try to keep this thread as clear as possible.

Physicsguy1

@sgal said:

Object can be linked to more than one joint, and vice versa.

Actually, Connecting two objects to a single controlled joint will not work correctly. Either object will take on a static position once the simulation is commenced.

CPhillips

Thanks Everyone!! Its coming together great.

I am going to leave some posts in place for a while in case the author wants to update it. I will move any changes to main faq.

Don't forget you can embed images and even youtube videos.

Thanks!
Chris

Wacov

How do thrusters, magnets and emitters work?

Thrusters, magnets and emitters are all settings you can apply to any physics body in your model, using the UI; the thruster option will propel the object with a constant force along its Y (Blue) axis (However, this can be changed using the formula box). The power is user defined, and is dynamic, able to accept formulas and Ruby Script; a setting of 0 is off, so you can use something like joybutton("a")*1000 for runtime control.

Magnets affect any 'magnetic' objects nearby, with a force that can be defined much like that of the thruster. In this case, a negative value will push magnetic objects away, and, again, 0 is off. The setting for 'magnetic' can also be found in the UI; note that it's possible to turn both settings on for a single object.

Emitters create copies of themselves, which can be created with momentum along their Y axis. The lifetime setting dictates how many frames the emitted objects will remain; in this case, a setting of 0 will cause them to remain for the duration of the simulation. Strength is the momentum of the object when it is created, and rate is the number of frames between emissions; a setting of 0 for either of these will turn it off. These are dynamic, so you can turn emitters on and off, change their power and the rate of fire all during the simulation, using a formula or script. Note that complex 'objects' like a vehicle made up of many jointed groups cannot be emitted. Emitted items also lose a variety of settings applied to the parent object, such as whether it's hidden, any state changes, and any Thruster, Magnet or Emitter settings.

NewOne

Is there a User Manual for SketchyPhysics3 or not (yet)? I remember that for SP2 was a website http://sketchyphysicstutorial.googlepages.com/, but I don't know if is something for SP3.

Sgal

Use of the joints 2
Other thpes of joints

Corkscrew: Object linked to this joint can spin around his axe and move between maximum and minimum.
Spring: Object linked to this joint can move linearily along his axe. The spring joint will try to bring back them to the first position.
Ball: Object linked to this joint can rotate freely around the joint. The object axe points to the joint.
Universal: Object linked to this joint can rotate almost freely around the joint. Unlike the Ball one, the Universal joint won't allow the object to rotate around his axe. See those images (I found them in an old post of CPhillips) to understand the concept:
http://www10.atwiki.jp/bambooflow/?plugin=ref&serial=19
http://www.impulse-based.de/manual_images/balljoint.jpg

Sgal

Thanks to =Physicsguy= for the correction.
I think that an "official" SP manual is a primary need. This plug-in is growing too complex for an immediate comprension for a new user. Maybe a Wiki...

CPhillips

Cleaned up the thread a bit. Yeah the faq is getting sort of long. Maybe it should be moved to the new Wiki.

darkPhysics

[*]How do I make a simple objects

You can make simple objects using the SketchySolids toolbar as you will se in Flash file.

Link: http://rapidshare.de/files/46603991/untitled_demo.swf.html

Mitchieboy

I still don't know how to activate trusters.. I want to make my jetski work.... please anyone HELP!

rfresa

@cphillips said:

Now that you have installed SketchUp, use the following link to view the latest SketchyPhysics downloads...
http://code.google.com/p/sketchyphysics2/downloads/list?can=1&q=&sort=-uploaded&colspec=Filename%20Summary%20Uploaded%20Size%20DownloadCount
Again, run it, and follow the on screen prompts. It will install itself in the SketchUp Plugins folder.

This is just for windows, right? Because SketchyPhysics never installed itself on my mac. I finally figured it out, but some more info on how to install would be appreciated. For mac users that are reading this: Put the downloaded, extracted files in this folder: username/Library/Application Support/Google Sketchup 7/Sketchup/plugins.

I had to create the plugins folder because it wasn't there. Then I got another bug, "Error Loading File SketchyPhysics.rb
undefined method `file_loaded?' for main:Object"

I found many references to this bug, but no answers, until I found this tip from fernandogalin on the issues page (http://code.google.com/p/sketchyphysics/issues/detail?id=9

copy sketchup.rb from Tools folder to Plugins folder
edit sketchyphysics.rb from Plugins folder and add this line at the begining of the
file: load "sketchup.rb"

This solved my problem and now I can use SketchyPhysics, which I love! This is the awesomest plugin ever. Hopefully this info will save some others from going through the same confusion that I did, so they can get to the good part.

togethearth

Mmmh, not sure if this thread is still active.
BTW, I'd like to share my 2 cents work with the community, I "updated" the Quick Reference Card (mostly for togethearth MAC users at first):
http://togethearth.com/files/SketchyPhysics_QuickReference_Card_MAC.pdf

If other Mac users find it useful let me know.

jonesey429

Is there a plugin for SketchUp that computes electrical systems voltage, current, resistance? Or maybe a more complex plugin that accepts more variables?

sf741852963

why does my SketchyPhysics 3x freeze when I press play?

arjunmax09

where can i get tutorial for sketchyphysics 3...maybe a pdf file...??

CPhillips

http://sketchyphysics.wikia.com/wiki/SketchyPhysicsWiki

robint

Hi all

great stuff pls keep it up. I will try to add my 2 cents as i progress
I cant post any links or skp models to demo my points, this is very limiting

MikeR

i got a SketchUp v6 and want to try and learn sketchy physics. what version should i download? thanks

demigamer

hey guys
he says where emitters are; its such as ''hidden''

why? i want to make a twilight render
but even sketchyreplay doesn't see my emitters

can someone help me? its for a project so i need it

thanks anyway
greetz,demi