diff --git a/Manifest.toml b/Manifest.toml
deleted file mode 100644
index 4736669..0000000
--- a/Manifest.toml
+++ /dev/null
@@ -1,387 +0,0 @@
-# This file is machine-generated - editing it directly is not advised
-
-[[AxisArrays]]
-deps = ["Dates", "IntervalSets", "IterTools", "RangeArrays"]
-git-tree-sha1 = "d27a38eb4312c8c42ac144d10e17e4ce7fb27c55"
-uuid = "39de3d68-74b9-583c-8d2d-e117c070f3a9"
-version = "0.4.1"
-
-[[BangBang]]
-deps = ["Future", "InitialValues", "LinearAlgebra", "Requires", "Setfield", "ZygoteRules"]
-git-tree-sha1 = "6a721fca2a44ae40615712e6522ce1c12ac4726c"
-uuid = "198e06fe-97b7-11e9-32a5-e1d131e6ad66"
-version = "0.3.1"
-
-[[Base64]]
-uuid = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
-
-[[CEnum]]
-git-tree-sha1 = "62847acab40e6855a9b5905ccb99c2b5cf6b3ebb"
-uuid = "fa961155-64e5-5f13-b03f-caf6b980ea82"
-version = "0.2.0"
-
-[[ConstructionBase]]
-git-tree-sha1 = "a2a6a5fea4d6f730ec4c18a76d27ec10e8ec1c50"
-uuid = "187b0558-2788-49d3-abe0-74a17ed4e7c9"
-version = "1.0.0"
-
-[[DataStructures]]
-deps = ["InteractiveUtils", "OrderedCollections"]
-git-tree-sha1 = "b7720de347734f4716d1815b00ce5664ed6bbfd4"
-uuid = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
-version = "0.17.9"
-
-[[Dates]]
-deps = ["Printf"]
-uuid = "ade2ca70-3891-5945-98fb-dc099432e06a"
-
-[[Distributed]]
-deps = ["Random", "Serialization", "Sockets"]
-uuid = "8ba89e20-285c-5b6f-9357-94700520ee1b"
-
-[[Future]]
-deps = ["Random"]
-uuid = "9fa8497b-333b-5362-9e8d-4d0656e87820"
-
-[[GLEW_jll]]
-deps = ["Libdl", "Libglvnd_jll", "Pkg", "X11_jll", "Xorg_libXi_jll"]
-git-tree-sha1 = "cbc0778a866389f895e2101bd18ee23bc7b5182f"
-uuid = "bde7f898-03f7-559e-8810-194d950ce600"
-version = "2.1.0+2"
-
-[[GLFW_jll]]
-deps = ["Libdl", "Libglvnd_jll", "Pkg", "Xorg_libXcursor_jll", "Xorg_libXi_jll", "Xorg_libXinerama_jll", "Xorg_libXrandr_jll"]
-git-tree-sha1 = "3b04f1dd73f0efa81298a76c9515f306df06f613"
-uuid = "0656b61e-2033-5cc2-a64a-77c0f6c09b89"
-version = "3.3.2+0"
-
-[[InitialValues]]
-git-tree-sha1 = "ef18588a15dcd6aff37a09108d7b3754093d73be"
-uuid = "22cec73e-a1b8-11e9-2c92-598750a2cf9c"
-version = "0.2.2"
-
-[[InteractiveUtils]]
-deps = ["Markdown"]
-uuid = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
-
-[[IntervalSets]]
-deps = ["Dates", "Statistics"]
-git-tree-sha1 = "4214b48a62eb8f2c292b2ee34a508c256c0cdbc9"
-uuid = "8197267c-284f-5f27-9208-e0e47529a953"
-version = "0.3.2"
-
-[[IterTools]]
-git-tree-sha1 = "05110a2ab1fc5f932622ffea2a003221f4782c18"
-uuid = "c8e1da08-722c-5040-9ed9-7db0dc04731e"
-version = "1.3.0"
-
-[[LibGit2]]
-uuid = "76f85450-5226-5b5a-8eaa-529ad045b433"
-
-[[Libdl]]
-uuid = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
-
-[[Libgcrypt_jll]]
-deps = ["Libdl", "Libgpg_error_jll", "Pkg"]
-git-tree-sha1 = "9592d031aac2566fb5cf9eeb28e2d7b05db9b9ef"
-uuid = "d4300ac3-e22c-5743-9152-c294e39db1e4"
-version = "1.8.5+0"
-
-[[Libglvnd_jll]]
-deps = ["Libdl", "Pkg", "X11_jll", "Xorg_glproto_jll", "Xorg_libX11_jll", "Xorg_libXext_jll"]
-git-tree-sha1 = "b69bdcad2424615c7b0838f69608b541680a5b7e"
-uuid = "7e76a0d4-f3c7-5321-8279-8d96eeed0f29"
-version = "1.2.0+2"
-
-[[Libgpg_error_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "3332d872d131a6ee88f10f20d7d131ece886c424"
-uuid = "7add5ba3-2f88-524e-9cd5-f83b8a55f7b8"
-version = "1.36.0+0"
-
-[[Libiconv_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "802f5b23c846cb4ed568cae0bfb0ce0d2ba1926d"
-uuid = "94ce4f54-9a6c-5748-9c1c-f9c7231a4531"
-version = "1.16.0+1"
-
-[[LinearAlgebra]]
-deps = ["Libdl"]
-uuid = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
-
-[[Logging]]
-uuid = "56ddb016-857b-54e1-b83d-db4d58db5568"
-
-[[MacroTools]]
-deps = ["DataStructures", "Markdown", "Random"]
-git-tree-sha1 = "e2fc7a55bb2224e203bbd8b59f72b91323233458"
-uuid = "1914dd2f-81c6-5fcd-8719-6d5c9610ff09"
-version = "0.5.3"
-
-[[Markdown]]
-deps = ["Base64"]
-uuid = "d6f4376e-aef5-505a-96c1-9c027394607a"
-
-[[MuJoCo_jll]]
-deps = ["GLEW_jll", "GLFW_jll", "Libdl", "Libglvnd_jll", "Pkg"]
-git-tree-sha1 = "500ed43eebb61f915cc6910d3a9afda225655fcc"
-uuid = "32af7c3b-80ec-5621-8194-2f6cb2280831"
-version = "2.0.0+1"
-
-[[OrderedCollections]]
-deps = ["Random", "Serialization", "Test"]
-git-tree-sha1 = "c4c13474d23c60d20a67b217f1d7f22a40edf8f1"
-uuid = "bac558e1-5e72-5ebc-8fee-abe8a469f55d"
-version = "1.1.0"
-
-[[Pkg]]
-deps = ["Dates", "LibGit2", "Libdl", "Logging", "Markdown", "Printf", "REPL", "Random", "SHA", "Test", "UUIDs"]
-uuid = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
-
-[[Printf]]
-deps = ["Unicode"]
-uuid = "de0858da-6303-5e67-8744-51eddeeeb8d7"
-
-[[REPL]]
-deps = ["InteractiveUtils", "Markdown", "Sockets"]
-uuid = "3fa0cd96-eef1-5676-8a61-b3b8758bbffb"
-
-[[Random]]
-deps = ["Serialization"]
-uuid = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
-
-[[RangeArrays]]
-git-tree-sha1 = "b9039e93773ddcfc828f12aadf7115b4b4d225f5"
-uuid = "b3c3ace0-ae52-54e7-9d0b-2c1406fd6b9d"
-version = "0.3.2"
-
-[[Reexport]]
-deps = ["Pkg"]
-git-tree-sha1 = "7b1d07f411bc8ddb7977ec7f377b97b158514fe0"
-uuid = "189a3867-3050-52da-a836-e630ba90ab69"
-version = "0.2.0"
-
-[[Requires]]
-deps = ["Test"]
-git-tree-sha1 = "f6fbf4ba64d295e146e49e021207993b6b48c7d1"
-uuid = "ae029012-a4dd-5104-9daa-d747884805df"
-version = "0.5.2"
-
-[[SHA]]
-uuid = "ea8e919c-243c-51af-8825-aaa63cd721ce"
-
-[[Serialization]]
-uuid = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
-
-[[Setfield]]
-deps = ["ConstructionBase", "Future", "MacroTools", "Requires"]
-git-tree-sha1 = "ed5045722fcdacf263a90fb9eb9f258598ccebac"
-uuid = "efcf1570-3423-57d1-acb7-fd33fddbac46"
-version = "0.5.4"
-
-[[Sockets]]
-uuid = "6462fe0b-24de-5631-8697-dd941f90decc"
-
-[[SparseArrays]]
-deps = ["LinearAlgebra", "Random"]
-uuid = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
-
-[[StaticArrays]]
-deps = ["LinearAlgebra", "Random", "Statistics"]
-git-tree-sha1 = "5a3bcb6233adabde68ebc97be66e95dcb787424c"
-uuid = "90137ffa-7385-5640-81b9-e52037218182"
-version = "0.12.1"
-
-[[Statistics]]
-deps = ["LinearAlgebra", "SparseArrays"]
-uuid = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
-
-[[Test]]
-deps = ["Distributed", "InteractiveUtils", "Logging", "Random"]
-uuid = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
-
-[[UUIDs]]
-deps = ["Random", "SHA"]
-uuid = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
-
-[[Unicode]]
-uuid = "4ec0a83e-493e-50e2-b9ac-8f72acf5a8f5"
-
-[[UnsafeArrays]]
-git-tree-sha1 = "1de6ef280110c7ad3c5d2f7a31a360b57a1bde21"
-uuid = "c4a57d5a-5b31-53a6-b365-19f8c011fbd6"
-version = "1.0.0"
-
-[[X11_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "dfadaea7e3fa9120b06824b634342fc6cba58109"
-uuid = "546b0b6d-9ca3-5ba2-8705-1bc1841d8479"
-version = "1.6.8+5"
-
-[[XML2_jll]]
-deps = ["Libdl", "Libiconv_jll", "Pkg", "Zlib_jll"]
-git-tree-sha1 = "ed5603a695aefe3e9e404fc7b052e02cc72cfab6"
-uuid = "02c8fc9c-b97f-50b9-bbe4-9be30ff0a78a"
-version = "2.9.9+1"
-
-[[XSLT_jll]]
-deps = ["Libdl", "Libgcrypt_jll", "Pkg", "XML2_jll"]
-git-tree-sha1 = "77d0086a876532cb4fae005d4c9ecc8236dcdceb"
-uuid = "aed1982a-8fda-507f-9586-7b0439959a61"
-version = "1.1.33+0"
-
-[[Xorg_fixesproto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "101dcd548d6021b8d3cdaeb66c65c0d85faf1bcb"
-uuid = "cf2f014d-5496-555f-b295-889ac9dfddaa"
-version = "5.0.0+0"
-
-[[Xorg_glproto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "16cb7bf73d86119bffe90d3ae7dd17b12281c887"
-uuid = "41595b7c-9afa-5287-863f-896d3380052a"
-version = "1.4.17+0"
-
-[[Xorg_inputproto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "a941739b553f589cd264dc16fdeaf5300af30f51"
-uuid = "84d6cd60-beca-5f49-93c5-789031781a2d"
-version = "2.3.2+0"
-
-[[Xorg_kbproto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "d0991fb63a9c663108bc5adc2ebdf358be6a289f"
-uuid = "060dd47b-79ec-5ba1-a7b2-f4f2f7dcdd0f"
-version = "1.0.7+0"
-
-[[Xorg_libX11_jll]]
-deps = ["Libdl", "Pkg", "Xorg_inputproto_jll", "Xorg_kbproto_jll", "Xorg_libxcb_jll", "Xorg_util_macros_jll", "Xorg_xextproto_jll", "Xorg_xproto_jll", "Xorg_xtrans_jll"]
-git-tree-sha1 = "a48b5faf2a95933d1249c889a2893f7701935bcb"
-uuid = "4f6342f7-b3d2-589e-9d20-edeb45f2b2bc"
-version = "1.6.8+0"
-
-[[Xorg_libXau_jll]]
-deps = ["Libdl", "Pkg", "Xorg_xproto_jll"]
-git-tree-sha1 = "8cc829c6223f11f06b56108c45e6b1aad13b1fdc"
-uuid = "0c0b7dd1-d40b-584c-a123-a41640f87eec"
-version = "1.0.9+0"
-
-[[Xorg_libXcursor_jll]]
-deps = ["Libdl", "Pkg", "Xorg_libXfixes_jll", "Xorg_libXrender_jll", "Xorg_util_macros_jll"]
-git-tree-sha1 = "0632e71a9d45f56a84b2cb517773918f3d54ddf3"
-uuid = "935fb764-8cf2-53bf-bb30-45bb1f8bf724"
-version = "1.2.0+0"
-
-[[Xorg_libXdmcp_jll]]
-deps = ["Libdl", "Pkg", "Xorg_util_macros_jll", "Xorg_xproto_jll"]
-git-tree-sha1 = "1cb581254dd38106e9cfb2c6aa1ed675547fd2e4"
-uuid = "a3789734-cfe1-5b06-b2d0-1dd0d9d62d05"
-version = "1.1.3+0"
-
-[[Xorg_libXext_jll]]
-deps = ["Libdl", "Pkg", "Xorg_libX11_jll", "Xorg_util_macros_jll", "Xorg_xextproto_jll"]
-git-tree-sha1 = "08b8a06261eec5fbe45d4077a993a224af2880e3"
-uuid = "1082639a-0dae-5f34-9b06-72781eeb8cb3"
-version = "1.3.4+0"
-
-[[Xorg_libXfixes_jll]]
-deps = ["Libdl", "Pkg", "Xorg_fixesproto_jll", "Xorg_libX11_jll", "Xorg_util_macros_jll"]
-git-tree-sha1 = "d4194996acacdd25f4f86a40ea6b9e497d4c1604"
-uuid = "d091e8ba-531a-589c-9de9-94069b037ed8"
-version = "5.0.3+0"
-
-[[Xorg_libXi_jll]]
-deps = ["Libdl", "Pkg", "Xorg_inputproto_jll", "Xorg_libXext_jll", "Xorg_libXfixes_jll", "Xorg_util_macros_jll"]
-git-tree-sha1 = "411b9503eb1dd7af3605e51a4cf7e4850a75f20e"
-uuid = "a51aa0fd-4e3c-5386-b890-e753decda492"
-version = "1.7.10+0"
-
-[[Xorg_libXinerama_jll]]
-deps = ["Libdl", "Pkg", "Xorg_libXext_jll", "Xorg_util_macros_jll", "Xorg_xineramaproto_jll"]
-git-tree-sha1 = "123ffa8c714ee630dde2256ad91d02322e079074"
-uuid = "d1454406-59df-5ea1-beac-c340f2130bc3"
-version = "1.1.4+0"
-
-[[Xorg_libXrandr_jll]]
-deps = ["Libdl", "Pkg", "Xorg_libXext_jll", "Xorg_libXrender_jll", "Xorg_randrproto_jll", "Xorg_util_macros_jll"]
-git-tree-sha1 = "122d70832769124a15f2a1623307f4637179b1b3"
-uuid = "ec84b674-ba8e-5d96-8ba1-2a689ba10484"
-version = "1.5.2+0"
-
-[[Xorg_libXrender_jll]]
-deps = ["Libdl", "Pkg", "Xorg_libX11_jll", "Xorg_renderproto_jll"]
-git-tree-sha1 = "07abd690ddd09818237a0a21359fd6ef449e820d"
-uuid = "ea2f1a96-1ddc-540d-b46f-429655e07cfa"
-version = "0.9.10+0"
-
-[[Xorg_libpthread_stubs_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "5c2806e6e08b093ca2071e53602651f4a5e079da"
-uuid = "14d82f49-176c-5ed1-bb49-ad3f5cbd8c74"
-version = "0.1.0+0"
-
-[[Xorg_libxcb_jll]]
-deps = ["Libdl", "Pkg", "XSLT_jll", "Xorg_libXau_jll", "Xorg_libXdmcp_jll", "Xorg_libpthread_stubs_jll", "Xorg_util_macros_jll", "Xorg_xcb_proto_jll"]
-git-tree-sha1 = "b3d001a3df5ec00fd677f0ae674127983218ac72"
-uuid = "c7cfdc94-dc32-55de-ac96-5a1b8d977c5b"
-version = "1.13.0+0"
-
-[[Xorg_randrproto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "5c2f995614980bedaed7de97995f9a5e0f857bef"
-uuid = "0e394dc1-71ae-5c65-abe5-8749687e42d3"
-version = "1.5.0+0"
-
-[[Xorg_renderproto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "36dbfa838fc4faf019a6957f2eb8c1b5f31bb500"
-uuid = "21e99dc2-7dba-5609-a726-b181bd3bbb6c"
-version = "0.11.1+0"
-
-[[Xorg_util_macros_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "a99f6275c9b2a9862d2cc4e714aad806c2daecc1"
-uuid = "7c09cfe3-afe2-5798-bcc9-d6b7fecfdca5"
-version = "1.19.2+0"
-
-[[Xorg_xcb_proto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "1506cde098df4b6dedcc082bf9386a5808ee6dea"
-uuid = "c2e9c405-c068-5e7b-9b35-084fd074cae4"
-version = "1.13.0+0"
-
-[[Xorg_xextproto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "0a1da65671cfc3b20926081b668c7dd098dd9c76"
-uuid = "d13bc2ba-d276-5c6f-8a1c-29ed04aab5d0"
-version = "7.3.0+0"
-
-[[Xorg_xineramaproto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "9f331b569a18a4fbf66ee8f60cb4018c73faabb4"
-uuid = "6a3da44c-33b1-5374-838f-bf0fbf92c29b"
-version = "1.2.1+0"
-
-[[Xorg_xproto_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "fdb0d8bae06762e24dade427e7914d199cdd721e"
-uuid = "46797783-dccc-5433-be59-056c4bde8513"
-version = "7.0.31+0"
-
-[[Xorg_xtrans_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "b18f01c3b50be7bde08be131934112db3137f28b"
-uuid = "c5fb5394-a638-5e4d-96e5-b29de1b5cf10"
-version = "1.4.0+0"
-
-[[Zlib_jll]]
-deps = ["Libdl", "Pkg"]
-git-tree-sha1 = "fd36a6739e256527287c5444960d0266712cd49e"
-uuid = "83775a58-1f1d-513f-b197-d71354ab007a"
-version = "1.2.11+8"
-
-[[ZygoteRules]]
-deps = ["MacroTools"]
-git-tree-sha1 = "b3b4882cc9accf6731a08cc39543fbc6b669dca8"
-uuid = "700de1a5-db45-46bc-99cf-38207098b444"
-version = "0.2.0"
diff --git a/Project.toml b/Project.toml
index 5993676..81d5612 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "MuJoCo"
 uuid = "93189219-7048-461c-94ec-443a161ed927"
 authors = ["Colin Summers", "Kendall Lowrey"]
-version = "0.3.0"
+version = "0.3.1"
 
 [deps]
 AxisArrays = "39de3d68-74b9-583c-8d2d-e117c070f3a9"
@@ -15,16 +15,6 @@ Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 UnsafeArrays = "c4a57d5a-5b31-53a6-b365-19f8c011fbd6"
 
-[compat]
-AxisArrays = "0.4.1"
-BangBang = "< 0.3.2"
-CEnum = "0.2"
-MacroTools = "0.5.3"
-Reexport = "0.2"
-StaticArrays = "0.12.1"
-UnsafeArrays = "1"
-julia = "1.3"
-
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
diff --git a/src/MJCore/util.jl b/src/MJCore/util.jl
index 2f78d58..5162417 100644
--- a/src/MJCore/util.jl
+++ b/src/MJCore/util.jl
@@ -149,4 +149,4 @@ getglobal(::Val{name}, ::Type{T}) where {name,T} = cglobal((name, libmujoco), T)
 function storeglobal!(::Val{name}, ::Type{T}, x) where {name,T}
     ptr = getglobal(Val(name), T)
     Base.unsafe_store!(ptr, Base.unsafe_convert(T, Base.cconvert(T, x)))
-end
\ No newline at end of file
+end
diff --git a/src/MJCore/wrapper/mjmujoco.jl b/src/MJCore/wrapper/mjmujoco.jl
index 2c60bef..0e5b3dd 100644
--- a/src/MJCore/wrapper/mjmujoco.jl
+++ b/src/MJCore/wrapper/mjmujoco.jl
@@ -2424,6 +2424,158 @@ function mju_writeLog(type::String, msg::String)
 end
 
 
+#---------------------- Quaternions ----------------------------------------------------
+
+"""Rotate vector by quaternion."""
+function mju_rotVecQuat(res::MJVec, vec::MJVec, quat::MJVec)
+    @assert length(res) >= 3
+    @assert length(vec) >= 3
+    @assert length(quat) >= 4
+    ccall(
+          (:mju_rotVecQuat, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}, Ptr{mjtNum}),
+          res, vec, quat
+         )
+end
+
+"""Conjugate quaternion, corresponding to opposite rotation."""
+function mju_negQuat(res::MJVec, quat::MJVec)
+    @assert length(res) >= 4
+    @assert length(quat) >= 4
+    ccall(
+          (:mju_negQuat, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}),
+          res, quat
+         )
+end
+
+"""Muiltiply quaternions."""
+function mju_mulQuat(res::MJVec, quat1::MJVec, quat2::MJVec)
+    @assert length(res) >= 4
+    @assert length(quat1) >= 4
+    @assert length(quat2) >= 4
+    ccall(
+          (:mju_mulQuat, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}, Ptr{mjtNum}),
+          res, quat1, quat2
+         )
+end
+
+"""Muiltiply quaternion and axis."""
+function mju_mulQuatAxis(res::MJVec, quat::MJVec, axis::MJVec)
+    @assert length(res) >= 4
+    @assert length(quat) >= 4
+    @assert length(axis) >= 3
+    ccall(
+          (:mju_mulQuatAxis, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}, Ptr{mjtNum}),
+          res, quat, axis
+         )
+end
+
+
+"""Convert axisAngle to quaternion."""
+function mju_axisAngle2Quat(res::MJVec, axis::MJVec, angle::mjtNum)
+    @assert length(res) >= 4
+    @assert length(axis) >= 3
+    ccall(
+          (:mju_axisAngle2Quat, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}, mjtNum),
+          res, axis, angle
+         )
+end
+
+"""Convert quaternion (corresponding to orientation difference) to 3D velocity."""
+function mju_quat2Vel(res::MJVec, quat::MJVec, dt::mjtNum)
+    @assert length(res) >= 3
+    @assert length(quat) >= 4
+    ccall(
+          (:mju_quat2vel, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}, mjtNum),
+          res, quat, dt
+         )
+end
+
+"""Subtract quaternions, express as 3D velocity: qb*quat(res) = qa."""
+function mju_subQuat(res::MJVec, qa::MJVec, qb::MJVec)
+    @assert length(res) >= 3
+    @assert length(qa) >= 4
+    @assert length(qb) >= 4
+    ccall(
+          (:mju_subQuat, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}, Ptr{mjtNum}),
+          res, qa, qb
+         )
+end
+
+"""Convert quaternion to 3D rotation matrix."""
+function mju_quat2Mat(res::MJVec, quat::MJVec);
+    @assert length(res) >= 9
+    @assert length(quat) >= 4
+    ccall(
+          (:mju_quat2Mat, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}),
+          res, quat
+         )
+end
+
+"""Convert 3D rotation matrix to quaterion."""
+function mju_mat2Quat(quat::MJVec, mat::MJVec)
+    @assert length(quat) >= 4
+    @assert length(mat) >= 9
+    ccall(
+          (:mju_mat2Quat, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}),
+          quat, mat
+         )
+end
+
+"""Compute time-derivative of quaternion, given 3D rotational velocity."""
+function mju_derivQuat(res::MJVec, quat::MJVec, vel::MJVec)
+    @assert length(res) >= 4
+    @assert length(quat) >= 4
+    @assert length(vel) >= 3
+    ccall(
+          (:mju_derivQuat, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}, Ptr{mjtNum}),
+          res, quat, vel
+         )
+end
+
+"""Integrate quaterion given 3D angular velocity."""
+function mju_quatIntegrate(quat::MJVec, vel::MJVec, scale::mjtNum)
+    @assert length(quat) >= 4
+    @assert length(vel) >= 3
+    ccall(
+          (:mju_quatIntegrate, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}, mjtNum),
+          quat, vel, scale
+         )
+end
+
+"""Construct quaternion performing rotation from z-axis to given vector."""
+function mju_quatZ2Vec(quat::MJVec, vec::MJVec)
+    @assert length(res) >= 4
+    @assert length(vec) >= 3
+    ccall(
+          (:mju_quatZ2vec, libmujoco),
+          Cvoid,
+          (Ptr{mjtNum}, Ptr{mjtNum}),
+          quat, vec 
+         )
+end
+
 
 #---------------------- Utility functions: miscellaneous -------------------------------
 
diff --git a/src/MuJoCo.jl b/src/MuJoCo.jl
index e944c43..9873f53 100644
--- a/src/MuJoCo.jl
+++ b/src/MuJoCo.jl
@@ -114,7 +114,7 @@ const CONTROL_FIELDS = (
 )
 
 # For @set!! macro to work
-@inline function BangBang.setproperties!(value::JLTypes, patch::NamedTuple)
+@inline function BangBang.setproperties!!(value::JLTypes, patch::NamedTuple)
     ntuple(length(patch)) do i
         setproperty!(value, keys(patch)[i], patch[i])
     end
diff --git a/test/MJCore/mjmujoco.jl b/test/MJCore/mjmujoco.jl
index 909a82f..de5f67a 100644
--- a/test/MJCore/mjmujoco.jl
+++ b/test/MJCore/mjmujoco.jl
@@ -102,12 +102,13 @@ end
             jf3 = getproperty(jd3, name)
             test() = jf1 == jf2 == jf3
 
-            if name === :solver_nnz
-                # TODO
-                @test_skip test()
-            else
-                @test test()
-            end
+            #if name === :solver_nnz
+            #    # TODO
+            #    @test_skip test()
+            #else
+            #    @test test()
+            #end
+            @test test()
 
             #if name === :solver_nnz
             #    # NOTE: bug in MuJoCo? d1.solver_nnz == 729,
@@ -128,4 +129,4 @@ end
         mj_copyData(jd2, jm, jd1)
         @test jd2.qpos == jd1.qpos
     end
-end
\ No newline at end of file
+end
diff --git a/test/runtests.jl b/test/runtests.jl
index c4899ff..e5ab411 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -40,5 +40,7 @@ end
 
 @testset "MuJoCo.jl" begin
     include("MJCore/MJCore.jl")
+    include("MJCore/mjmujoco.jl")
+    #include("MJCore/cglobals.jl")
     include("sugar.jl")
 end