point

问题 I have a triangle with points A, B, C and Point in space (P). How can I get distance from point to plane? I need to calc distance from P to plane, even when my triangle lie far away(or not above to the point, like on picture). Point and triangle: 回答1: If the point is P(x1,y1,z1) and the plane is ax+by+cz+d = 0 Distance dist = Abs(a*x1+b*y1+c*z1+d) / Sqrt(a^2+b^2+c^2) 回答2: I assume you want to compute perpendicular distance between point and plane given 3 points on it forming a triangle. Here

问题 I have a program where an entity moves around in two-dimensional space. To move one step, the entity picks its next point, and then sets it as his current point. Sometimes, however, the entity's next point lies in an Area (java.awt.geom.Area) that is forbidden (the "forbidden area" is actually a velocity obstacle). How can the entity pick the point outside the Area which is closest to the entity's preferred point? The Area is composed of different shapes (sometimes, the shapes are not

问题 I have a strange behavior of MySQL spatial search. I have created a polygon in a GEOM field (Portugal bounds), then I am trying to find a point inside -- it is found ok. The next try is to find a point that is outside a polygon but the query still returns 1 found row. Please help, what am I doing wrong? Why does it find a point outside a polygon? SQL Code for testing is below: CREATE TABLE IF NOT EXISTS `test` ( `id` int(11) NOT NULL AUTO_INCREMENT, `bounds` geometry NOT NULL, PRIMARY KEY (

问题 I have some point on a 2D grid (x, y) and I need to find all points that are n distance away from that point. The way I'm measuring distance is by using the distance formula between the two points. Anyone know how to do this? Edit: Just for reference, what I'm trying to do is to write some AI path finding that will maintain some distance away from a target in a system that uses grid based locations. Currently I'm using A* path finding, but I'm not sure if that matters or makes a difference

问题 I have created a class "Point" and i want to calculate the shortest distance between a given point and a line ( characterized by 2 other points ), all points are known. I tried to use this formula : |Ax+By+C| / sqrt(A^2+B^2) , but i messed up and got more confused by the minute (mostly because of math formulas :( )... I did find some sites where people asked this question too, but it either was not for Python or it was in a 3D system not 2D ... ​​ Below is my class : class Point: def __init__

问题 How to test if a point P = [xp,yp] is inside/outside some rotated ellipse given by the centre C=[x,y], a, b, and phi ( angle of rotation)? At this moment I am using the following solution: rotate ellipse and point by the angle -phi and then the common test for a position of the point and "non rotated" ellipse. But there are a lot of tested points (thousands) and I find this solution as slow. Is there any direct and more efficient way to get a position of the rotated ellipse and point? I do

问题 How to test if a point P = [xp,yp] is inside/outside some rotated ellipse given by the centre C=[x,y], a, b, and phi ( angle of rotation)? At this moment I am using the following solution: rotate ellipse and point by the angle -phi and then the common test for a position of the point and "non rotated" ellipse. But there are a lot of tested points (thousands) and I find this solution as slow. Is there any direct and more efficient way to get a position of the rotated ellipse and point? I do

问题 I am trying to code an java methods wich returns an boolean true if a point(x,y) is on a line segment and false if not. I tried this: public static boolean OnDistance(MyLocation a, MyLocation b, MyLocation queryPoint) { double value = java.lang.Math.signum((a.mLongitude - b.mLongitude) * (queryPoint.mLatitude - a.mLatitude) - (b.mLatitude - a.mLatitude) * (queryPoint.mLongitude - a.mLongitude)); double compare = 1; if (value == compare) { return true; } return false; } but it doesnt work.

问题 i tried in that way but i didnt get the needed results: System.Drawing.Point[] p = new System.Drawing.Point[6]; p[0].X = 0; p[0].Y = 0; p[1].X = 53; p[1].Y = 111; p[2].X = 114; p[2].Y = 86; p[3].X = 34; p[3].Y = 34; p[4].X = 165; p[4].Y = 7; g = PictureBox1.CreateGraphics(); g.DrawPolygon(pen1, p); what i want to do is to draw a polygon in picturebox which is defined with diffrent colors and according to the rates (the number of corner and coordinates of the edges ) 回答1: Create an xOffset

问题 I am looking for an algorithm to generate equally distributed points inside a polygon. Here is the scenario: I have a polygon specified by the coordinates of the points at the corners (x, y) for each point. And I have the number of points to generate inside the polygon. For example lets say I have a polygon containing 5 points: (1, 1) ; (1, 2) ; (2, 3) ; (3, 2) ; and (3, 1) And I need to generate 20 equally distanced points inside that polygon. Note: Some polygons may not support equally