Cuboid + Cylinder inconsistency, intersecting, zero distance but no contact

Michael · July 19, 2017, 4:46am

Hi,

I have a minimal test case of a cylinder + cuboid that have a distance of 0, proximity is “WithinMargin”, but no contact is being generated regardless of prediction.

gist.github.com

https://gist.github.com/MichaelShaw/4057fa515aff0c3277788753cd0bf729

cuboid_cylinder.rs

use nalgebra as na;
use ncollide as nc;
use nalgebra::{Isometry3, Vector3};
use ncollide::shape::{Cuboid, Cylinder};

let cyl = Cylinder::new(0.925, 0.5);
let cyl_at = Isometry3::new(Vector3::new(10.97, 0.925, 61.02), na::zero());
let cuboid = Cuboid::new(Vector3::new(0.05, 0.75, 0.5));
let cuboid_at = Isometry3::new(Vector3::new(11.52, 0.75, 60.5), na::zero());

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It’s quite finicky, if I subtract 60.0 off the z translation of both shapes, we get a contact being generated and the inconsistency is gone.

sebcrozet · July 19, 2017, 9:15pm

This is a bug. Related github issue: sebcrozet/ncollide#157.