# Neoshaman

Member

559

180 Neutral

• Rank

• Interests
Art
Audio
Design
DevOps
Production
Programming
1. ## Ray intersection on (axis aligned) swept curve?

I'm struggling to find the correct way to make ray intersection with curve that are swept along an axis.In theory I thought it should be simple, I decompose the problem into component:- find intersection on the curve (cross section), which is easy- extrude that intersection point into an axis aligned line, solve the slope intersection to that line to get the final offset.To be sure I got it right, I'm starting with a swept 45° line centered on origin (line-plane intersection with dot product would be more efficient, but remember I'm trying to validating swiping a long a line).- line equation is origine + directionVector * t- line to line intersection equation is t = (origine1 - origine2)/(directionVector2 - directionVector1) >> assuming they are never parallel.So let line2dIntersection(directionVector1,origine1,directionVector2,origine2)Assuming the ray start on the xy plane (pseudo code):- I first compute the cross section into xzintersection1 = line2dIntersection(rayDir.xz, vector2(origine.x,0), vector2(1,1).normalize(), vector2(0,0));result.xz = raydir.xz * intersection1;-Then find the slope swipe offset into yzintersection2 = line2dIntersection(rayDir.yz, vector2(origine.y,0), vector2(1,0).normalize(), vector2(0,result.z));result.y = raydir.y * intersection2;But all my result are garbage. What am I doing wrong? where is the leap of logic I did?