Wedding…

Quaternions don’t automatically solve gimbal lock problems. For example, when you create a quaternion from Eulerian or Cardanian angles, or when you create a quaternion per rotation axis and then you multiply them, it doesn’t solve your problem at all. Why? Because you can’t use quaternions with no Euler’s angles. At least you use them during the initialisation of quaternions and modification and the true problem comes from the way to combine rotations: R=Rx.Ry.Rz which leads sometimes to lose a degree of freedom. It happens when you turn 0, 90, 180, 270 degrees around Oy for example. Don’t hesitate sending me emails if you need more explanations because I may never come back here.

An other interessting point about Sandy 0.2 is the event sytem. It will completely change, and be more powerfull thnaks too pixlib (see Osflash.org/pixlib/). I think it’s a really good change, but not yet integrated into Sandy, Christmas first

I’m by no means a 3d guru. I used to use quaternions while playing with opengl, and i thought that i’d make a suggestion. But if you say that they didnt fit well in sandy, i’ll take your word for that
i’m looking forward to give sandy 0.2 a try.

regards
cornel

In fact I have a complete Quaternion class, but I still don’t use it in the engine. Quaternion are useful when you want to store a rotation objet (so 4 properties compare to 16!) or when you what to remove the Gimbal Lock effect common with Euler angles. But (!) I’ve never seen so far this effect during my experiment, so I prefer to keep Matrix.
Moreover Sandy allows to mix scale and rotation as transformation for a group. So if I use Quaternion in the core I must transform the quaternion into a MAtrix to apply the multiplication. And in this case quaternion’s use will be slower.

But I’m not an expert of quaternions, so if I said something wrong, please say it (and explain also, I need to learn too )

Merry Christmas Everybody

about the rotation (camera or whatever), what about beign handled with quaternions? Instead of something like:
myCamera.setYaw(…)
myCamera.setPitch(…)
…
one could do something like:
myCamera.setRotation(new Quaternion(1,0,0,90))

just my 0.02$
what do you think?

merry christmas!
cornel

I don’t believe this answers my question. It appears that the plane is still parallel to the XY plane.

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But I don’t like the fact to separate HPlane to VPlane… Will change soon too
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Excellent!

But I don’t like the fact to separate HPlane to VPlane… Will change soon too