Quote:if it's for a game, you'd be better of to make it up. Then you can tweak the gameplay as you wish (add more mass since the ship is more powerful than expected, ect...).
I second that.. and a ship's density isn't constant, you could have a very small ship that weights the same or more than a larger ship, how do you determine the average density?
the same for all ships? quite restrictive... :/
by hand? then you'd better just set their weight by hand in the first place, and then you won't need their density...
anyway.. that's just my opinion.. if you still want to compute their volume, you can use the method Dmytry described in the other thread. (link's somewhere up on this page)
I use that method too and it works fine.
just take the AABB height and lower Y bound, place the virtual projection plane at min.y - (height * 0.1) (the relative offset is here just to avoid some imprecisions if the meshes you want to measure vary widely in size, then just ignore the Y coordinate of the triangles, compute the 2D area (dot product), and do area * (v0->y + v1->y + v2->y) / 3.0f, and add these values for each triangle to an accumulator. in the end, you'll get the volume.
he gave some visual explanations in the other thread if I recall correctly... might be clearer :)
note that if your mesh isn't closed, you will have volume "leaking" in or out, depending if the "hole" is located on the top or bottom of the mesh... anyway, make sure the mesh is completely closed.