From c8e839a6662199cf94153906e1b11790dbe3e04d Mon Sep 17 00:00:00 2001
From: Alessio Quaglino <quaglino@google.com>
Date: Wed, 24 Jan 2024 09:36:27 -0800
Subject: [PATCH] Do not create contact if there are no DOFs.

PiperOrigin-RevId: 601146599
Change-Id: I68b1975a3217b266bbbfb0a15c85a65cfa46facb
---
 src/engine/engine_core_constraint.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/engine/engine_core_constraint.c b/src/engine/engine_core_constraint.c
index fbb8ff9a..0916ab22 100644
--- a/src/engine/engine_core_constraint.c
+++ b/src/engine/engine_core_constraint.c
@@ -908,7 +908,7 @@ void mj_instantiateContact(const mjModel* m, mjData* d) {
   mjContact* con;
   mjtNum cpos[6], cmargin[6], *jac, *jacdif, *jacdifp, *jacdifr, *jac1p, *jac2p, *jac1r, *jac2r;
 
-  if (mjDISABLED(mjDSBL_CONTACT) || ncon == 0) {
+  if (mjDISABLED(mjDSBL_CONTACT) || ncon == 0 || nv == 0) {
     return;
   }