SketchyPhysics3 Release Candidate 1
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I mean like the setvar and getvar scripts. Can it be alterable during the simulation?
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Still not following. What is get/setVar not doing?
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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.
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@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!
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The physics material would be entirely separate from the SketchUp material; so you'd be able to set a box to behave like wood, but it could be painted as steel. These materials would be like templates, with settings you can modify, like density and friction. Maybe a material manager could be implemented? The UI's kinda crowded.
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@wacov said:
The physics material would be entirely separate from the SketchUp material; so you'd be able to set a box to behave like wood, but it could be painted as steel. These materials would be like templates, with settings you can modify, like density and friction. Maybe a material manager could be implemented? The UI's kinda crowded.
If it's going to work that way, then it'll be perfect, as long as we can make our own material of course. Do you know for sure that's how it'll be, or you're just guessing?
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That's how it SHOULD be IF it's implemented. That's (I think) how it works in the newton physics playground, so the same kind of thing could be done with SP.
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@wacov said:
That's how it SHOULD be IF it's implemented. That's (I think) how it works in the newton physics playground, so the same kind of thing could be done with SP.
Makes perfect sense to me.
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Hey,how do you make magnets and thrusters work? I can't seem to make them work.
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For an uncontrollable thruster, check the box placed next to thruster in the UI. Then put in a simple value like 5000 in the strength field. If it is a big object, then the number must be increased. A controlled thruster code(placed in strength field)will be like this: -(controller)*value. A simple example will be -(key('space'))*5000. You can replace space with any character on the keyboard. If you have a joystick, you can put in just A or B or X or Y for the buttons. You can also put in lefty or leftx, being y axis and x axis respectively. You can do the same with right in the place of left, for the right stick(if you have one) Remember that if you don't have a joystick, you can still control the lefty and righty with the keyboard. Lefty is w/a/s/d, and righty for the arrow keys. For magnets, check the magnet box in the UI. Then enter a value. Create another object and check the magnetic box. The magnetic object will cling to the magnet. Try a higher value. You can also control magnets. Hope this helps!
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Thanks
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@unknownuser said:
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.
Ok, I think I understand. Right now you can only get variables that have been set. That may change at some point.
What var did you want to change?
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@alienizer said:
@wacov said:
The physics material would be entirely separate from the SketchUp material; so you'd be able to set a box to behave like wood, but it could be painted as steel. These materials would be like templates, with settings you can modify, like density and friction. Maybe a material manager could be implemented? The UI's kinda crowded.
If it's going to work that way, then it'll be perfect, as long as we can make our own material of course. Do you know for sure that's how it'll be, or you're just guessing?
Yes that is more or less how it works. If it was just a matter of setting mass it would be easy, but it also has all the other properties of a material like friction.
Part of the problem is that you need to setup material to material values. So if you have wood and ice you have a wood/wood table and a ice/ice table and a wood/ice table. Then if you add say steel then you need all those plus steel/steel and steel/wood and steel/ice. As you can see it adds up to a lot of tables to fill in. The UI is going to be tricky.
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@cphillips said:
Yes that is more or less how it works. If it was just a matter of setting mass it would be easy, but it also has all the other properties of a material like friction.
Part of the problem is that you need to setup material to material values. So if you have wood and ice you have a wood/wood table and a ice/ice table and a wood/ice table. Then if you add say steel then you need all those plus steel/steel and steel/wood and steel/ice. As you can see it adds up to a lot of tables to fill in. The UI is going to be tricky.
Why the need for material to material values? If one material has more friction than another one, it shouldn't make any difference what material it comes into contact with, because both material will then be evaluated to simulate the proper friction, say, rock(friction=10) on glass(friction=1) will slide more than rock(friction=10) on rock(friction=10)
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I dont know. That how the physics engine is setup.
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I suppose that could be useful; something like rubber could have the same friction value as rock, but it'd stick to glass really well.
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What I'm really interseted to know is if we can use multiple physics materials in the static mesh... so you could have slippery mud next to rock and sand, all with their own settings. I've noticed that the realism becomes pretty unreliable if you use more than one static mesh in a large model, so that's not really an option.
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I think the material interaction should not be done using the "material to material" approach. We should use the laws of physics. In real life, what make rubber stick to glass? Well, there is how porous the object is, its flexibility, how smooth it is. That's 3 things I can think of right now. Having settings such as these for each material would simplify the task, and then we would not need to do material to material.
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Unfortunately, flexible (deformable) geometry is totally impossible with the current engine. You could probably make stuff bounce, but that's it. Bouyancy would be a useful setting, but as far as porous objects... maybe something can increase gradually in density when it enters the bouyancy plane? True fluid simulation has already been ruled out, although some physics engines support it, SU probably can't handle dynamic geometry that complex. I see what you're saying about smoothness though.
I agree with you, but specific settings could come in handy. Maybe there could be a general blanket effect, but with user-defined exceptions? The laws of physics have already been thrown out of the window
... flying cars, anyone? -
Miss a few days, and get left in the dust... So much can change in a week!
...oh, on mac, after installation, why do I get the message
%(#FF0000)[Error Loading File sketchyphysics.rb
no such file to load -- dl]I must have done SOMETHING wrong... tried it twice to no avail...
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