Geometry Point under the mouse

[Alexey Vanzhula]

I can find primitive under the mouse with MouseCHOP.

Now i wat to find closest point at this primitive.

The problem is that nearpoint expression function return near point to viewport plane. As the result I can find valid point number in flat grid and via one of ortho views.

How to properly find closest point ? I have to consider direction (in my code) returned by mapToWorld. But How ?

import hou, toolutils

cur_viewport = toolutils.sceneViewer().curViewport()   # CURRENT VIEWPORT
mx, my = hou.evalParmTuple("/obj/geo1/dm1/core/mouse") # THIS IS PATH TO MOUSE-CHOP
vx, vy = v.mapFromMouseChop(mx,my)                     # GET VIEWPORT COORDINATES
direction, position =v.mapToWorld(vx,vy)               # CONVERT VIEWPORT TO WORLD COORDINATES

node = cur_viewport.queryNodeAtPixel(vx, vy)           # NODE AT WORLD COORDINATES

if node is not None:
    prim = v.queryPrimAtPixel( node, vx, vy )          # PRIM AT WORLD COORDINATES
    hou.hscriptExpression( 'nearpoint("{}",{},{},{})'.format(node.path(), position[0], position[1], position[2]) )      # POINT NUMBER

[Storm Keeper]

Alexey, my solution is to use origin and ray vectors and then iterate over the primitive's vertices to find minimal distance to the ray. Here is my code: 

def getN(point, orig, dir):
    pos = point.position()
    OP = pos - orig
    proj = OP.dot(dir)
    n = OP - proj * dir
    return n

def nearestPrimPoint(prim, orig, dir):
    minD = float('inf')
    nearestPoint = prim.vertices()[0].point()

    for v in prim.vertices():
        P = v.point()
        N = getN(P, orig, dir)
        D = N.length()
            
        if D < minD:
            minD = D
            nearestPoint = P
                
    return nearestPoint

So you can pass the direction and position vectors to this function.

Edited June 17, 2014 by Dmitry Shurov

[Alexey Vanzhula]

Thanx, i`ll try it