CGTalk How to find the angle betwen two vectors
 07-30-2004, 08:18 PM #1 fabman Anywhere but here..   portfolio Fabian choqueiro! from hell somewhere, España   Join Date: Aug 2002 Posts: 201 How to find the angle betwen two vectors I got two vectors A and B as Point3, how could I find the 3 eulerangles between them, I look in the manual but I can't find a "simple" method to do it. What I wan't to do is to copy the result rotation on to other object rotations. Thank you in advance. __________________ Mathematics, rightly viewed, possesses not only truth, but supreme beauty - a beauty cold and austere, like that of sculpture. share quote
 07-30-2004, 10:02 PM #2 lechoo Frequenter     Join Date: May 2004 Posts: 117 Hi, I think you can use quats. Here's my idea: calculate cross product of A and B. Put its x,y,z into quat's x,y,z. Thats your rotation vector, now you need angle. Equation is very simple: ang = acos((A.x*B.x+A.y*B.y+A.z*B.z) / ((length A)*(length B))). ang is w part of quat. Now simply convert quat to eulerangles using "as eulerangles". I think it should work but never tried that. share quote
 07-30-2004, 10:45 PM #3 gdimmrt Frequenter   Join Date: Aug 2003 Posts: 230 Look up "Dot Product" in the MS reference manual. share quote
 08-02-2004, 09:30 AM #4 Wahooney Demon Onion Slayer   portfolio Keith Boshoff 3D Artist - Programmer - Scribe - Blender Wannabe - Max Enthusiast Durban, South Africa   Join Date: May 2004 Posts: 976 There is actually only one angle between two vectors (in relation to eachother). You can get that value like this: ang = acos (dot vec1 vec2) Note that the vectors must be normalized. To get the angle of a vector in worldspace you're gonna hafta use some trig. share quote
 01-18-2006, 09:00 PM #5 CGTalk Moderation Expert   Join Date: Sep 2003 Posts: 1,066,478 Thread automatically closed This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum. __________________ CGTalk Policy/Legalities Note that as CGTalk Members, you agree to the terms and conditions of using this website. share quote