jmol-developers

 Re: FW: Re: [Jmol-developers] Ribbon Algo From: Miguel - 2005-10-04 22:39:05 ```> > Hello and thanks for your reply .hermite curve are drawn b/w two points= > and how to calculate tangent vector .if P1 is CA1 and C2 is CA2 then ho= w > to calculate T1 and T2 > > To calculate a hermite curve you need the following vectors: P1: the > startpoint of the curve T1: the tangent (e.g. direction and speed) to h= ow > the curve leaves the startpoint P2: he endpoint of the curve T2: the > tangent (e.g. direction and speed) to how the curves meets the endpoint= Per my other message ... With this curve I calculate the tangents T1 and T2 by using the points P0= and P4. However, looking at the code, I realize that my other message may have given you the wrong answer regarding how T1 and T2 are calculated. Lookin= g at the code: int x1 =3D p1.x, y1 =3D p1.y, z1 =3D p1.z; int x2 =3D p2.x, y2 =3D p2.y, z2 =3D p2.z; int xT1 =3D ((x2 - p0.x) * tension) / 8; int yT1 =3D ((y2 - p0.y) * tension) / 8; int zT1 =3D ((z2 - p0.z) * tension) / 8; int xT2 =3D ((p3.x - x1) * tension) / 8; int yT2 =3D ((p3.y - y1) * tension) / 8; int zT2 =3D ((p3.z - z1) * tension) / 8; So, T1 =3D=3D (xT1, yT1, zT1) and T2 =3D=3D (xT2, yT2, zT2) T1 =3D P2 - P0 T2 =3D P3 - P1 The 'tension' factor is just a number 0-8 that controls the magnitude of those vectors. Miguel ----- Open Source Molecular Visualization http://www.jmol.org miguel=40jmol.org ----- ```