diff --git a/indra/llmath/llrigginginfo.cpp b/indra/llmath/llrigginginfo.cpp
new file mode 100644
index 000000000..0de07950c
--- /dev/null
+++ b/indra/llmath/llrigginginfo.cpp
@@ -0,0 +1,159 @@
+/**
+* @file llrigginginfo.cpp
+* @brief  Functions for tracking rigged box extents
+*
+* $LicenseInfo:firstyear=2018&license=viewerlgpl$
+* Second Life Viewer Source Code
+* Copyright (C) 2018, Linden Research, Inc.
+*
+* This library is free software; you can redistribute it and/or
+* modify it under the terms of the GNU Lesser General Public
+* License as published by the Free Software Foundation;
+* version 2.1 of the License only.
+*
+* This library is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+* Lesser General Public License for more details.
+*
+* You should have received a copy of the GNU Lesser General Public
+* License along with this library; if not, write to the Free Software
+* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*
+* Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+* $/LicenseInfo$
+*/
+
+#include "llmath.h"
+#include "llrigginginfo.h"
+
+//-----------------------------------------------------------------------------
+// LLJointRiggingInfo
+//-----------------------------------------------------------------------------
+LLJointRiggingInfo::LLJointRiggingInfo()
+{
+    mRiggedExtents[0].clear();
+    mRiggedExtents[1].clear();
+    mIsRiggedTo = false;
+}
+
+bool LLJointRiggingInfo::isRiggedTo() const
+{
+    return mIsRiggedTo;
+}
+
+void LLJointRiggingInfo::setIsRiggedTo(bool val)
+{
+    mIsRiggedTo = val;
+}
+    
+LLVector4a *LLJointRiggingInfo::getRiggedExtents()
+{
+    return mRiggedExtents;
+}
+
+const LLVector4a *LLJointRiggingInfo::getRiggedExtents() const
+{
+    return mRiggedExtents;
+}
+
+// Combine two rigging info states.
+// - isRiggedTo if either of the source infos are rigged to
+// - box is union of the two sources
+void LLJointRiggingInfo::merge(const LLJointRiggingInfo& other)
+{
+    if (other.mIsRiggedTo)
+    {
+        if (mIsRiggedTo)
+        {
+            // Combine existing boxes
+            update_min_max(mRiggedExtents[0], mRiggedExtents[1], other.mRiggedExtents[0]);
+            update_min_max(mRiggedExtents[0], mRiggedExtents[1], other.mRiggedExtents[1]);
+        }
+        else
+        {
+            // Initialize box
+            mIsRiggedTo = true;
+            mRiggedExtents[0] = other.mRiggedExtents[0];
+            mRiggedExtents[1] = other.mRiggedExtents[1];
+        }
+    }
+}
+
+LLJointRiggingInfoTab::LLJointRiggingInfoTab():
+    mRigInfoPtr(NULL),
+    mSize(0),
+    mNeedsUpdate(true)
+{
+}
+
+LLJointRiggingInfoTab::~LLJointRiggingInfoTab()
+{
+    clear();
+}
+
+// This doesn't preserve data if the size changes. In practice
+// this doesn't matter because the size is always either
+// LL_CHARACTER_MAX_ANIMATED_JOINTS or 0.
+void LLJointRiggingInfoTab::resize(S32 size)
+{
+    if (size != mSize)
+    {
+        clear();
+        if (size > 0)
+        {
+            mRigInfoPtr = new LLJointRiggingInfo[size];
+            mSize = size;
+        }
+    }
+}
+
+void LLJointRiggingInfoTab::clear()
+{
+    if (mRigInfoPtr)
+    {
+        delete[](mRigInfoPtr);
+        mRigInfoPtr = NULL;
+        mSize = 0;
+    }
+}
+
+void showDetails(const LLJointRiggingInfoTab& src, const std::string& str)
+{
+	S32 count_rigged = 0;
+	S32 count_box = 0;
+    LLVector4a zero_vec;
+    zero_vec.clear();
+    for (S32 i=0; i<src.size(); i++)
+    {
+        if (src[i].isRiggedTo())
+        {
+            count_rigged++;
+            if ((!src[i].getRiggedExtents()[0].equals3(zero_vec)) ||
+                (!src[i].getRiggedExtents()[1].equals3(zero_vec)))
+            {
+                count_box++;
+            }
+       }
+    }
+    LL_DEBUGS("RigSpammish") << "details: " << str << " has " << count_rigged << " rigged joints, of which " << count_box << " are non-empty" << LL_ENDL;
+}
+
+void LLJointRiggingInfoTab::merge(const LLJointRiggingInfoTab& src)
+{
+    //showDetails(*this, "input this");
+    // Size should be either LL_CHARACTER_MAX_ANIMATED_JOINTS, or 0 if
+    // no data. Not necessarily the same for both inputs.
+    if (src.size() > size())
+    {
+        resize(src.size());
+    }
+    S32 min_size = llmin(size(), src.size());
+    for (S32 i=0; i<min_size; i++)
+    {
+        (*this)[i].merge(src[i]);
+    }
+    //showDetails(src, "input src");
+    //showDetails(*this, "output this");
+
+}
diff --git a/indra/llmath/llrigginginfo.h b/indra/llmath/llrigginginfo.h
new file mode 100644
index 000000000..b3d6bc2d1
--- /dev/null
+++ b/indra/llmath/llrigginginfo.h
@@ -0,0 +1,100 @@
+/**
+* @file llrigginginfo.h
+* @brief  Functions for tracking rigged box extents
+*
+* $LicenseInfo:firstyear=2018&license=viewerlgpl$
+* Second Life Viewer Source Code
+* Copyright (C) 2018, Linden Research, Inc.
+*
+* This library is free software; you can redistribute it and/or
+* modify it under the terms of the GNU Lesser General Public
+* License as published by the Free Software Foundation;
+* version 2.1 of the License only.
+*
+* This library is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+* Lesser General Public License for more details.
+*
+* You should have received a copy of the GNU Lesser General Public
+* License along with this library; if not, write to the Free Software
+* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*
+* Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+* $/LicenseInfo$
+*/
+
+// Stores information related to associated rigged mesh vertices
+// This lives in llmath because llvolume lives in llmath.
+
+#ifndef	LL_LLRIGGINGINFO_H
+#define	LL_LLRIGGINGINFO_H
+
+#include "llvector4a.h"
+
+// Extents are in joint space
+// isRiggedTo is based on the state of all currently associated rigged meshes
+LL_ALIGN_PREFIX(16)
+class LLJointRiggingInfo
+{
+public:
+    LLJointRiggingInfo();
+    bool isRiggedTo() const;
+    void setIsRiggedTo(bool val);
+    LLVector4a *getRiggedExtents();
+    const LLVector4a *getRiggedExtents() const;
+    void merge(const LLJointRiggingInfo& other);
+
+	void* operator new(size_t size)
+	{
+		return ll_aligned_malloc_16(size);
+	}
+
+	void operator delete(void* ptr)
+	{
+		ll_aligned_free_16(ptr);
+	}
+
+	void* operator new[](size_t size)
+	{
+		return ll_aligned_malloc_16(size);
+	}
+
+	void operator delete[](void* ptr)
+	{
+		ll_aligned_free_16(ptr);
+	}
+
+
+private:
+	LL_ALIGN_16(LLVector4a mRiggedExtents[2]);
+    bool mIsRiggedTo;
+} LL_ALIGN_POSTFIX(16);
+
+// For storing all the rigging info associated with a given avatar or
+// object, keyed by joint_num.
+// Using direct memory management instead of std::vector<> to avoid alignment issues.
+class LLJointRiggingInfoTab
+{
+public:
+    LLJointRiggingInfoTab();
+    ~LLJointRiggingInfoTab();
+    void resize(S32 size);
+    void clear();
+    S32 size() const { return mSize; }
+    void merge(const LLJointRiggingInfoTab& src);
+    LLJointRiggingInfo& operator[](S32 i) { return mRigInfoPtr[i]; }
+    const LLJointRiggingInfo& operator[](S32 i) const { return mRigInfoPtr[i]; };
+    bool needsUpdate() { return mNeedsUpdate; }
+    void setNeedsUpdate(bool val) { mNeedsUpdate = val; }
+private:
+    // Not implemented
+    LLJointRiggingInfoTab& operator=(const LLJointRiggingInfoTab& src);
+    LLJointRiggingInfoTab(const LLJointRiggingInfoTab& src);
+
+    LLJointRiggingInfo *mRigInfoPtr;
+    S32 mSize;
+    bool mNeedsUpdate;
+};
+
+#endif