From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Wed, 29 Nov 2017 19:40:00 +0000 (+0000)
Subject: helixish: fix tilt sense
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=4632b1defebe17221058527d2217d5c7e56eca22;p=moebius3.git

helixish: fix tilt sense

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/helixish.py b/helixish.py
index dde107d..a4519a2 100644
--- a/helixish.py
+++ b/helixish.py
@@ -142,8 +142,8 @@ class HelixishCurve():
     tilt = atan(start_mu)
     tilt_basis = np.array([
       [ 1,     0,           0,         0 ],
-      [ 0,   cos(tilt), -sin(tilt),    0 ],
-      [ 0,   sin(tilt),  cos(tilt),    0 ],
+      [ 0,   cos(tilt),  sin(tilt),    0 ],
+      [ 0,  -sin(tilt),  cos(tilt),    0 ],
       [ 0,     0,           0,         1 ],
     ])
     findcurve_basis = matmatmultiply(dPQplane_basis, tilt_basis)