From fe28e350e96a8b137354e9038c6d25a9145d068d Mon Sep 17 00:00:00 2001 From: Mai Lavelle Date: Wed, 14 Sep 2016 19:34:43 -0400 Subject: [PATCH] Fix T49179: Parts of mesh disappear with adaptive subdivision Problem was zero length normal caused by a precision issue in patch evaluation. This is somewhat of a quick fix, but is better than allowing possible NaNs to occur and cause problems elsewhere. --- intern/cycles/render/mesh_subdivision.cpp | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/intern/cycles/render/mesh_subdivision.cpp b/intern/cycles/render/mesh_subdivision.cpp index c8cc3abf7d9..3b4841f5b20 100644 --- a/intern/cycles/render/mesh_subdivision.cpp +++ b/intern/cycles/render/mesh_subdivision.cpp @@ -284,7 +284,12 @@ struct OsdPatch : Patch { if(dPdu) *dPdu = du; if(dPdv) *dPdv = dv; - if(N) *N = normalize(cross(du, dv)); + if(N) { + *N = cross(du, dv); + + float t = len(*N); + *N = (t != 0.0f) ? *N/t : make_float3(0.0f, 0.0f, 1.0f); + } } BoundBox bound() { return BoundBox::empty; }