peanutandchestnut的专栏

Rotate direction:  get your coordinate hand, align your thumb to the rotation axes,  winding direction of other finger will be our rotate directionMathematic script:unitX = UnitVector[3, 1]unitY

O is arbitary pointAB = t ACConclusionOB = (1 - t)OA + t OCif 0 if t > 1,   point B is on right side of Cif t Proof:OB = OA + AB       = OA +  t(OC - OA)       = (1 - t)OA + t OC

conclusion:if T is orthogonaln'  = Tnelse       n' = inverse(transpose(T))nProof: normal n, arbitray point p1, p2  on plane. dot(n, (p1- p2)) = 0          ==>             transpose(n)(p1

Format:1. Ax + By + Cz + D = 0;2. dot(n, p) + d = 0,   d = - dot(n, p)          //p = {x, y, z}        3. dot(L, P) = 0            // L = [n, d],  //P = {x, y, z, 1}, the same as p in homogeno

It's pretty easy to find loop with help of mathematicaLet's say i want to scale a ball in 3d spacei want it to start as original onethan get bigger and bigger as time goes bywhen it's big en

Some thing i should know about atant2:Most content of this article copyed from wikipediaThe purpose of using two arguments instead of one is to gather information on the signs of the inputs in ord