SketchyPhysics3 Release Candidate 1

CPhillips · 26 Mar 2009, 22:21

This version is basically done. But needs a bit of testing and bug fixing before it can be a 3.0.

There are a few new features and a bunch of fixes.

The first new feature is a new fixed joint type. Its handy when connecting thrusters or magnets to other bodies. The second feature is the fixed joint is also breakable. The third is that bodys can now have no collision. What this is useful for will become apparent latter on.

Also a few new script commands.

setVar("foo",1.0)

will set the variable "foo" to 1.0.

getVar("foo")

will now be equal to 1.0.

Variables will be saved until the simulation is reset. And they are global. That means any object can see them. So a formula in say a thruster can get and set a variable that a servo also uses (for example).

Most of the fixes were to get the Mac WebDialogs to behave. So there may be bugs there. On Mac you can apparently still loose a fields contents if you dont click away from the field before you select an object in Sketchup.

I also removed the copy on double click feature. It was seldom used and was getting in the way of other features.

Demos to follow...

Changes:
Added Fixed joint type.
Made fixed joint breakable.
Added ablity for objects to be nonsolid via nocollision flag
-Removed copy on doubleclick option.
-Removed copy menu item.
Added Mac dynlibs to installer.
Fix blurry buttons on Mac
Suppress key sound on Mac control panel.
Fixed some of the Mac WebDialog focus problems.
Added image export option to SketchyReplay
Fixed bug where sliders wouldnt show up for some fields.
More error and type checking on formulas.
Added setVar and getVar commands
Added getSetVar() command. Not totally thrilled about the name or the concept.
Added frame number to status bar while running.
Fixed bug in webdialogs to do with "hard spaces"

Windows installer:
http://sketchyphysics2.googlecode.com/files/SketchyPhysics3RC1-WinInstaller.exe

Mac (and Windows) version as a Zip:
http://sketchyphysics2.googlecode.com/files/SketchyPhysics3RC1-MacAndWin-Fixed.zip
Edit Mar 30:
Updated Mac version with missing .bundle file.

xrok1 · 27 Mar 2009, 01:13

i love how it saves the position of the camera at start, i was just thinking that would be great before i installed the new ver.

PS the new breakable joints aren't too bad either.

CPhillips · 27 Mar 2009, 01:39

I forgot I added that. Its actually a fix. It used to work, but broke at some point in the distant past.

Alienizer · 27 Mar 2009, 03:57

Perhaps not the right place to ask this question (to CPhillips) but, what is the reason for not having a "weight" attribute?

shareck · 27 Mar 2009, 13:51

can someone tell me how do i use image export option thats been added to sketchy replay?

CPhillips · 27 Mar 2009, 19:41

No weight because objects dont have materials yet. Thats planned for SPIV.

Image export is in the Plugins->SketchyReplay->Export animation dialog.

Note Replay still doesnt support emitted objects.

Alienizer · 27 Mar 2009, 22:33

@cphillips said:

No weight because objects dont have materials yet. Thats planned for SPIV.

I'm confused CPhillips. What do materials have to do with the weight of an object? If we make a box and assign 12lb to it, then it doesn't matter if it's solid or hollow, or what material it is, isn't it??

CPhillips · 27 Mar 2009, 22:58

I wish I could just say I weigh 180 and have it be so.

In short the physics engine doesn't support absolute weighting of stuff.

In physics as in real life the weight (mass) of something is determined by how much stuff in it and how dense it is. Steel is denser then wood so it weighs more. Thats why the physics engine uses materials.

Wacov · 28 Mar 2009, 13:13

I think mass is determined by density and volume, but weight is determined by mass and gravity. Objects in a weightless environment still have mass... but maybe you could insert a tool that tells you an object's weight, in the thruster power it would take to make it neutrally 'bouyant' in the air?

Oh and can you make the camera reset remember the field of view setting?

CPhillips · 28 Mar 2009, 19:11

Maybe. But I dont know how to change the fov.

Wacov · 28 Mar 2009, 19:49

Camera/Field of view

Drag like the zoom tool or type a number... but I'm not sure if that's what you mean...

CPhillips · 28 Mar 2009, 20:32

I guess so. But when I do that the simulation resets. How does it get changed in the course of a simulation. I need to know so I know when to save it.

Wacov · 28 Mar 2009, 20:56

It isn't! That's the problem! It resets to the default 30 degrees, when the simulation started at 70. This happens in MotorSketch Mesa, at least to me.

CPhillips · 29 Mar 2009, 01:08

Ah. I see. Yeah Ill fix.

Physicsguy1 · 29 Mar 2009, 01:33

Is it possible to alter variables within the simulation? I mean being able to control it with keyboard or joystick. I don't want a consistent position. Is that possible? If so, can you give me a script example?

CPhillips · 29 Mar 2009, 01:36

Be a little more specific..

Physicsguy1 · 29 Mar 2009, 02:12

I mean like the setvar and getvar scripts. Can it be alterable during the simulation?

CPhillips · 29 Mar 2009, 02:33

Still not following. What is get/setVar not doing?

Physicsguy1 · 29 Mar 2009, 02:43

I might not be right. When you wrote that it will retrieve the variable, i thought you could change the variable, like on a control panel slider. it is like two joints controlled with the same name.

Alienizer · 29 Mar 2009, 03:15

@cphillips said:

I wish I could just say I weigh 180 and have it be so.

In short the physics engine doesn't support absolute weighting of stuff.

In physics as in real life the weight (mass) of something is determined by how much stuff in it and how dense it is. Steel is denser then wood so it weighs more. Thats why the physics engine uses materials.

I understand what you are saying CPhillips, but without density, mass, weight or whatever we call it, some simulations can not be done properly. If you collide a ball of steel with a ball of wood, both of the same size (not mass), the simulation is very incorrect, they both propel in equal force, and that's way wrong. It doesn't matter for gravity as object of different weight will fall at the same speed, but when they collide, it's a new ball game. Material should not be used for this purpose, an object should have a "Mass,Density or whatever" attribute that we can set, regardless of what material we use. Material is for the look.

Take a look at your demo of the car you just did. When the whole car hit the wheel of another, it breaks off, at the same rate as if a wheel hit that wheel. Not very realistic don't you think? Not just for your car demo, but for other simulations. Say, a pool table where the 9 ball is made of gold, then what? it act just as the rest of the balls, that's just not right! We should be able to drop a rock on a piece of wood and have it react realistically. I piece of wood can't just hit a rock and make it fly off the ground!