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Post by Kjelle69 on Aug 23, 2004 4:44:42 GMT 1
Rigid Body Designer This program lets you setup the primitives to describe a complex object for use with Newton. you visually adjust the boxes/spheres to fit your object, and then save to a custom binary .bod file format I have designed. then with a single command you can load an object into the Newton world, with all of the Newton settings intact. The demo comes with the designer itself, and a test program that allows you to load .bod files into a simple Newton world. Anyone interested, please give it a try (even just to test the loader- the download comes with a few sample .bod files) and let me know if you run into any bugs/problems. after the TGC compo is over I'll probably release this system (including the .bod loader) for everyone to use. DOWNLOAD LINK - approx 3.3MB
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Post by Physicscoder on Aug 23, 2004 5:56:42 GMT 1
Wow amazing! In just a couple minutes I was able to make very percise collision for my tank model: And works just great in the load body program too! I have some ideas that might improve it a bit(if it could get any better): I like the set mass thing for the boxes and spheres in the editor, but would it be possible to have a set density button? it would get the volume and multiply it by the density. A subtle change would be having the Calc inertia not ask have the "box or sphere" question. Instead, if it's not too hard, you could have the program remeber the shape of an object when it's built(like 0 for box, 1 for sphere, and 2 or 3 for a cone and and cylinder shape when they are available) and use it then and when caculating. Something you could add is a zoom in/out feature. One last thing that could make it better would be 'set position', 'set rotation', and 'set size' buttons to directly set the attributes of the object. Very cool program .
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Post by Kjelle69 on Aug 23, 2004 6:14:28 GMT 1
good suggestions. I think if I were to release the program, a "set position/rotation/scale" button would be necessary. it wouldn't be too hard to add, I'll do it.
you can zoom by clicking and draggin the middle mouse button.
remember the mass and Intertia settings are for the object as a whole, not each individual piece.
-a note about the Inertia calculator - it bases the size of the object on the current selected object. so if you select a single primitive, it uses the size of that primitive and the mass to calculate the Inertia. the best way is to select the visual object, and then calculate the Inertia based on it (thus it asks you for box/sphere calculation).
one question - what would you use the density for? perhaps to aid in buoyancy settings?
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Post by zircher on Aug 23, 2004 15:49:40 GMT 1
Density would have a distinct impact on mass and thus how impulses would affect an object. A chain made out of balsa wood would react differently from one made out steel. Especially of there are external elements such as wind. Having a set density/mass function would allow the builder to play with those values. -- TAZ
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Post by Physicscoder on Aug 23, 2004 18:42:08 GMT 1
oh i thought the mass/inertia commands were for each object and were merged into one mass and inertia when saved. thats why i thought of a having density, because then you would be able to set each box or sphere to the same density.
another idea: i don't know if it would be possible, but it would be cool if this program, or some other editor, allowed you to connect things with joints. like a rigid body connector. just an idea.
anyways, very cool.
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Post by Kjelle69 on Aug 24, 2004 9:08:33 GMT 1
but Newton doesn't require the density itself... do you mean that you could set a desired density, and the program would calculate the proper mass based on the (approximated) object volume? that's an interesting idea... something to think about down the line. right now the priority is to get these tools to a working point, so I can use them to create my game. perhaps after the compo is over I'll go back and make them more user-friendly, and release them as a big Newton expansion pack the other editor is my Ragdoll Designer, which is almost complete as well. I'll make a post for it when it's ready too, so people can try it. it should make setting up ragdolls MUCH MUCH easier than any current methods, and will output a file compatible with realtime ragdoll generation
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Post by zircher on Aug 24, 2004 15:53:35 GMT 1
Right, in my mind's eye I can see an option to select water, flesh, stone, steel, glass, etc. and the program would calculate the mass required for that volume.
I suspect that one reason why some objects behave like they are in slow motion might be because they have the mass of feathers rather than armor or flesh. -- TAZ
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Post by Kjelle69 on Aug 25, 2004 1:26:47 GMT 1
I can see how setting mass via density would be useful. but I don't think it' the cause of the "slo motion" syndrome.
that is usually a result of unrealistic object scale. for example, you set gravity to -10.0 (approximately real life), but you object is 30 units big. in this scale, that's a 30 meter object! and you're probably placing it 100 meters above the ground!! that would take a while to fall down!!
however another common problem is unbalances masses as well... and a density based calculation system might help with some of these problems.
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Post by zircher on Aug 25, 2004 15:04:34 GMT 1
Does Newton make the general assumption that one unit in world space is equal to one meter? Or is it truly a matter of scale for objects and forces? -- TAZ
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Post by Kjelle69 on Aug 26, 2004 5:35:13 GMT 1
Newton maked no assumptions... you can use any scale you want, as long as you stay consistent with it. like I mentioned, if you object is 30 units big, your gravity, mass, and world size should reflect that scale. that being said, it has been mentioned on the Newton forums that Newton works best with the standard scale of: 1 length unit = 1 meter 1 mass unit = 1 kg 1 time unit = seconds. therefore, velocities would be m/s, and accel would be m/s^2 but again, for something like games... I think just adjusting the values until they "feel right" is all that really matters. but I'm still going to try and adhere to the above scale on my projects, just to be safe
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Post by Kjelle69 on Aug 26, 2004 5:38:24 GMT 1
hey physicscoder, could you send me your tank model + the .bod file you made? I'd love to test it here on my computer too, just to see a user-made .bod file working. or if anyone would like to send me their models+.bod files to test, that would be cool!! I'm hoping to have the Ragdoll Designer tool beta ready by this weekend too. ;D
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Post by Physicscoder on Aug 26, 2004 19:19:41 GMT 1
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Post by Kjelle69 on Aug 27, 2004 2:46:04 GMT 1
nice! it works great!
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Post by Physicscoder on Aug 27, 2004 17:39:24 GMT 1
lol looks like my tank isn't on the same scale as the sheep.
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aaa11
Newton Scholar
Posts: 117
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Post by aaa11 on Sept 18, 2008 4:00:08 GMT 1
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