Not Finding Expected Intersections, Issues with `mrmeshpy.rayMeshIntersect

[doknicilija98]

Hello,

I am currently working on a project that involves finding specific intersections with meshes using the mrmeshpy.rayMeshIntersect function. However, I am encountering some issues where the function does not return the expected intersections.

Here is a detailed description of my problem:

Problem Description

I am defining a line between two points that should intersect with a mesh, but the intersection is not being detected. Conversely, another line that should not intersect the mesh is being reported as intersecting.

Case 1: No Intersection Found (Unexpected)

The following line should intersect the mesh, but mrmeshpy.rayMeshIntersect does not find an intersection.

# Define two points that have the same x and z values and y values that are on opposite extremes
# Idea is to find first point on the mesh that intersects this line
point = mm.Vector3f(-27.2912, -27.0518, 19.9674)
end_point = mm.Vector3f(-27.2912, 26.1744, 19.9674)

line = mm.Line3f(point, end_point)
result = mm.rayMeshIntersect(aligner, line).mtp


# Output: AttributeError: 'NoneType' object has no attribute 'mtp'. It didn't find an intersection

Case 2: Intersection Found (Unexpected)

This line should not intersect the mesh, yet an intersection is reported.

from meshlib import mrmeshpy as mm 

point = mm.Vector3f(-29.2912, -27.0518, 19.9674)
end_point = mm.Vector3f(0.146456, 1, 0)

line_2 = mm.Line3f(point, end_point)
result = mm.rayMeshIntersect(aligner, line_2)

# Output: Vector3f[-29.0674, 12.9527, 19.9674]

Visualization

To visualize the lines, I combined contours with two points and the circular profile to create a mesh.

line = mm.Contours3f()
line.resize(1)
line[0].resize(2)
line[0][0] = point
line[0][1] = end_point

line = mm.makeMovementBuildBody(profile, line)

Here is an image that illustrates the situation:

The lower line finds an intersection but at the point 2, while upper line that has

Request for Help

I would appreciate any insights or suggestions on the following:

1. Why might mrmeshpy.rayMeshIntersect fail to find intersections in Case 1?
2. Why does it report an intersection in Case 2 when none is expected?
3. Are there any specific properties or configurations of the Line3f , rayMeshIntersect , or Mesh plotting that I might be overlooking?

Thank you for your assistance.

[Grantim]

Hello!

Looks like you are creating Line object with two ends of the line, but it takes one end and direction on input:

point = mm.Vector3f(-27.2912, -27.0518, 19.9674)
end_point = mm.Vector3f(-27.2912, 26.1744, 19.9674)

# wrong
#line = mm.Line3f(point, end_point)

# correct
line = mm.Line3f(point, end_point-point)