From e4eb6545737e4812656c4e3e4c9b177f3678026e Mon Sep 17 00:00:00 2001 From: Yuval Tassa Date: Sun, 27 Jul 2025 04:53:55 -0700 Subject: [PATCH] Updates `joint/ref` attribute documentation to clarify that the initial model configuration is unmodified. PiperOrigin-RevId: 787679025 Change-Id: I4eab9d2ea1b411d40c780c087fa44ccff0b10094 --- doc/XMLreference.rst | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/doc/XMLreference.rst b/doc/XMLreference.rst index 28d97205..8c4b9431 100644 --- a/doc/XMLreference.rst +++ b/doc/XMLreference.rst @@ -2161,10 +2161,11 @@ rotations as unit quaternions. :at:`ref`: :at-val:`real, "0"` The reference position or angle of the joint. This attribute is only used for slide and hinge joints. It defines the - joint value corresponding to the initial model configuration. The amount of spatial transformation that the joint - applies at runtime equals the current joint value stored in mjData.qpos minus this reference value stored in - mjModel.qpos0. The meaning of these vectors was discussed in the :ref:`Stand-alone ` section in - the Overview chapter. + joint value corresponding to the initial model configuration. Note that the initial configuration itself is + unmodified, only the value of the joint at this configuration. The amount of spatial transformation that the joint + applies at runtime equals the current joint value stored in ``mjData.qpos`` minus this reference value stored in + ``mjModel.qpos0``. The meaning of these vectors is discussed in the :ref:`Kinematic tree ` section in the + Overview chapter. .. _body-joint-springref: