Re: [Soya-user] Rotating, questions about basics.
After a brief chat with a few on the IRC, I thought I'd further specify what I'm trying to do: Let this be the top view of a box (which one day may be the base of a miniature counter). 12 || 34 I want to pivot this box around the Y axis but centered using either vertex 1 or 2 such that after a 90 degree rotation (chosen because its easier in ASCII): 3--1 | | 4--2 Note that 2 is at the same position as before the rotation. So, if 2's coordinates was originally (0.5, 0, 0), the line defined by the points: a = soya.Point(self.parent,0.5,0.0,0.0) b = soya.Point(self.parent,0.5,1.0,0.0) should intersect both 2 and the vertex under. However, the line self.rotate(proportion * 5.0, a, b) doesn't rotate the box but instead make it spiral out of view. Interestingly, for: a = soya.Point(self.parent,0.0,0.0,0.0) b = soya.Point(self.parent,0.0,1.0,0.0) works as expected (same as rotate_y). while the almost identical a = soya.Point(self.parent, 0.001, 0.0, 0.0) b = soya.Point(self.parent, 0.0, 1.0, 0.0) Propels the box toward in the -Z direction exptremely fast (which suggest a very, very far away axis of rotation.) I figured that out by multiplying proportion by 0.001 instead of 5.0. I'm assuming that I'm missing something, but this behaviour is confusing to me. Christian ___ Soya-user mailing list Soya-user@gna.org https://mail.gna.org/listinfo/soya-user
Re: [Soya-user] Rotating, questions about basics.
Where is the box? Is it just at the origin of its parent world? After a brief chat with a few on the IRC, I thought I'd further specify what I'm trying to do: Let this be the top view of a box (which one day may be the base of a miniature counter). 12 34 I want to pivot this box around the Y axis but centered using either vertex 1 or 2 such that after a 90 degree rotation (chosen because its easier in ASCII): 3--1 4--2 Note that 2 is at the same position as before the rotation. So, if 2's coordinates was originally (0.5, 0, 0), the line defined by the points: a = soya.Point(self.parent,0.5,0.0,0.0) b = soya.Point(self.parent,0.5,1.0,0.0) should intersect both 2 and the vertex under. However, the line self.rotate(proportion * 5.0, a, b) doesn't rotate the box but instead make it spiral out of view. It sounds really like your co-ordinates are somehow confused, as you noted elsewhere it seems like the origin of the rotation is far away. If your cube wasn't at 0,0,0 in the parent world, that would cause this kind of problem for instance. More general code, which might also fix this bug, could specify the axis of rotation in terms of your cube's co-ordinate system - then it would work anywhere. So you'd do soya.Point(self, co-ordinates relative to cubes centre) to define the points on the axis of rotation. Then wherever you move the cube in the parent world, you can always use this axis to rotate around that edge of the cube. Interestingly, for: a = soya.Point(self.parent,0.0,0.0,0.0) b = soya.Point(self.parent,0.0,1.0,0.0) works as expected (same as rotate_y). while the almost identical OK, that does seem strange given the other results. Cheers, Mark a = soya.Point(self.parent, 0.001, 0.0, 0.0) b = soya.Point(self.parent, 0.0, 1.0, 0.0) Propels the box toward in the -Z direction exptremely fast (which suggest a very, very far away axis of rotation.) I figured that out by multiplying proportion by 0.001 instead of 5.0. I'm assuming that I'm missing something, but this behaviour is confusing to me. Christian ___ Soya-user mailing list Soya-user@gna.org https://mail.gna.org/listinfo/soya-user -- Push Me Pull You - Distributed SCM tool (http://www.cl.cam.ac.uk/~maw48/pmpu/) ___ Soya-user mailing list Soya-user@gna.org https://mail.gna.org/listinfo/soya-user
Re: [Soya-user] Rotating, questions about basics.
On Sun, 2008-06-29 at 15:11 +0100, Mark Williamson wrote: Where is the box? Is it just at the origin of its parent world? (0,0,0) is halfway between 1 and 2. It sounds really like your co-ordinates are somehow confused, as you noted elsewhere it seems like the origin of the rotation is far away. You can get a spiral by changing the rotate call in basic-2.py from: self.rotate_y(proportion * 5.0) to: x = 0.01 self.rotate(proportion * 5.0,soya.Point(self.parent, x, 0, 0), soya.Point(self.parent,x,1,0)) However, for x = 0 it works normally (rotate around the centre without spiralling). If you use x=0.01 and use self instead of parent, the sword will fly off the screen in about 2 frames (while it really should be spinning around almost indistinguishably from rotate_y(...) ). I'm happy to hear of a work around, all that I want to do is to be able to wheel the box from either front corners (1 or 2) just as antique army units used to do to adjust their facing. Christian ___ Soya-user mailing list Soya-user@gna.org https://mail.gna.org/listinfo/soya-user
[Soya-user] Rotating, questions about basics.
Hi, I want to rotate a model along the y axis but using another centre than the parent's (0,0,0). To me, the following code in the class's advance_time should do the trick (to rotate around x=0.5 and z=0): self.rotate(proportion * 5, soya.Point(self.parent,0.5,0.0,0.0), soya.Point(self.parent,0.5,1.0,0.0)) Instead, I get a very rapidly enlarging spiral and the model goes off the view. The model is a simple box made in blender that was automatically imported. Can anyone help? Christian ___ Soya-user mailing list Soya-user@gna.org https://mail.gna.org/listinfo/soya-user
