Is there any way to modify an object's density?

[Shanbo Baddingham]

Hi, I want to make a physical object heavier by increasing its mass without increasing the volume.  Is there any way to do this?

[Rolig Loon]

No.  You can decrease it by making it hollow, but you can't increase it. 

[AnjoDaVinganca Ishtari]

make it  heavier?????

the things (objects) in SL dont have wight, yes its true.... if you rezz 1 object and drag it up to the air, it will stay in the air!!!! wich means.... you know.... .

well, continuing, maybe you are talking when you add object physics in the object tab in edit mode.... ok this is a different subject.... well, i presume that you want something to "fall", right? in order to acchieve that set, you will have to do it via script depending what you are trying to make.

physics only add them some propertys that make them act according  the envoirment and such.... like gravity, ok, but that can be a problem because of the SL presets on this...

other way to do this..... is... imagine its a cube with 10x10x10, easy.... copy it, make it 9.50x9.50x9.50, put it "inside" the first one and link it, do this process as many times you need.... visibly you will have 1 prim, but the object can be like... 2, 5, 100 prims linked, hiden "inside" the first one -  it will not have "amazing" results but its a good start....

Send me a message explaining exactlly what you are trying to make and i will help you with it

hope i helped you,

Anjo

[Freecilla Kuhn]

In the Object tab of the editor you can change the Material from wood to metal, rock, rubber etc. This will add different sounds.

Making a prim double or hollow changes nothing, the bigger it is the hard it is to push around, too big and you can not push it.

Falling speed has nothing to do with density in SL or real life, that depends on aerodynamics.

[Rolig Loon]

Actually, making it hollow does change its mass, as you would expect it to in either RL or SL. You can verify that by making two identical objects with this script in each:

 

default

{

touch_start(integer total_number)

{

llSay(0, (string)llGetMass());

}

}

 

Make one of them 95% hollow, then touch both. You'll see that the hollow one has a significantly lower mass. See also >>> http://wiki.secondlife.com/wiki/Mass_Lab In a similar way, you can also show that linking two identical prims together and moving one so that it occupies the same space as the other one doubles its mass. (So I was wrong in my initial response -- you CAN increase the object's density.) This does affect inertia and, hence, the amount of force you have to apply with llSetForce or llApplyImpulse, for example, to make a prim move. An application of a force (in newtons) equal to the object's mass (in kg) for one second will accelerate it to a velocity of 1 (in meters per second), which appears to be what happens with llApplyImpulse, for example.

[Freecilla Kuhn]

Rolig that's wild but I did try it many times in the past and just before I replied and I found the effect totally unnoticeable. I only made the prims and testing them by walking into them though. I did not add textures so I would not know which one was which.The numbers may add up but I really could not see any difference at all hmmm. Naturally I have to go try again lol.

Ok I'm back and yes it worked, hollow, solid and doubled are all a bit different. This time i did it on a FLAT prim instead of on the beach. Cool script too ty

[Rolig Loon]

You can't tell much by dragging them around with the mouse, unfortunately, or even by walking into them. The only real way to verify that changing their mass makes a difference is to apply a known force to them. Isaac Newton got it right ... F = m * a . If you write a little script with llApplyImpulse that whacks a prim with a specific force (F), you'll find that a more massive body doesn't accelerate anywhere near as fast as a less massive one. Try it with a pair of test objects like the ones I described earlier. It's kinda fun, and a nice in-world demo for a HS physics class.

[Freecilla Kuhn]

Walking into them seems to work, not a lot but you can tell, the double one you almost walk on it before pushing the other you only push...

 

you can try it out here if you like to http://slurl.com/secondlife/Sialimonus/86/123/43

[Rolig Loon]

Cool! I'll wander over this evening, when I can get in world.