diff --git a/src/geometry/group.h b/src/geometry/group.h
new file mode 100644
index 0000000..f9dc049
--- /dev/null
+++ b/src/geometry/group.h
@@ -0,0 +1,25 @@
+#ifndef __GEOMETRY_GROUP_H_INCLUDED__
+#define __GEOMETRY_GROUP_H_INCLUDED__
+
+#include "../common.h"
+#include <string.h>
+
+struct Group
+{
+	std::string name;
+	uint32_t numTriangles;
+
+	uint32_t GetSize() const;
+};
+
+inline uint32_t Group::GetSize() const
+{
+	uint32_t size = 0;
+
+	size += sizeof(char) * (name.size() + 1);       // name string (including null-terminator)
+	size += sizeof(uint32_t);                       // number of triangles
+
+	return size;
+}
+
+#endif
diff --git a/src/geometry/joint.h b/src/geometry/joint.h
new file mode 100644
index 0000000..cac5c33
--- /dev/null
+++ b/src/geometry/joint.h
@@ -0,0 +1,30 @@
+#ifndef __GEOMETRY_JOINT_H_INCLUDED__
+#define __GEOMETRY_JOINT_H_INCLUDED__
+
+#include "../common.h"
+#include "vector3.h"
+#include <string.h>
+
+struct Joint
+{
+	std::string name;
+	int32_t parentJointIndex;     // -1 = no parent
+	Vector3 position;
+	Vector3 rotation;
+
+	uint32_t GetSize() const;
+};
+
+inline uint32_t Joint::GetSize() const
+{
+	uint32_t size = 0;
+
+	size += sizeof(char) * (name.size() + 1);       // name string (including null-terminator)
+	size += sizeof(int32_t);                        // parent index
+	size += sizeof(float) * 3;                      // position
+	size += sizeof(float) * 3;                      // rotation
+
+	return size;
+}
+
+#endif
diff --git a/src/geometry/jointvertexinfo.h b/src/geometry/jointvertexinfo.h
new file mode 100644
index 0000000..93a5c00
--- /dev/null
+++ b/src/geometry/jointvertexinfo.h
@@ -0,0 +1,24 @@
+#ifndef __GEOMETRY_JOINTVERTEXINFO_H_INCLUDED__
+#define __GEOMETRY_JOINTVERTEXINFO_H_INCLUDED__
+
+#include "../common.h"
+
+struct JointVertexInfo
+{
+	uint32_t jointIndex;
+	float weight;
+
+	uint32_t GetSize() const;
+};
+
+inline uint32_t JointVertexInfo::GetSize() const
+{
+	uint32_t size = 0;
+
+	size += sizeof(uint32_t);                // joint index
+	size += sizeof(float);                   // weight
+
+	return size;
+}
+
+#endif
diff --git a/src/geometry/keyframe.h b/src/geometry/keyframe.h
new file mode 100644
index 0000000..0c29cb0
--- /dev/null
+++ b/src/geometry/keyframe.h
@@ -0,0 +1,46 @@
+#ifndef __GEOMETRY_KEYFRAME_H_INCLUDED__
+#define __GEOMETRY_KEYFRAME_H_INCLUDED__
+
+#include "../common.h"
+#include "vector3.h"
+
+struct Keyframe
+{
+	Keyframe(uint32_t numJoints);
+	virtual ~Keyframe();
+
+	uint32_t numJoints;
+	Vector3 *position;
+	Vector3 *rotation;
+
+	uint32_t GetSize() const;
+};
+
+inline Keyframe::Keyframe(uint32_t numJoints)
+{
+	this->numJoints = numJoints;
+	position = new Vector3[numJoints];
+	rotation = new Vector3[numJoints];
+}
+
+inline Keyframe::~Keyframe()
+{
+	SAFE_DELETE_ARRAY(position);
+	SAFE_DELETE_ARRAY(rotation);
+}
+
+inline uint32_t Keyframe::GetSize() const
+{
+	uint32_t singleJointFrameSize = 0;
+
+	singleJointFrameSize += (sizeof(float) * 3) * 3;               // position (xyz)
+	singleJointFrameSize += (sizeof(float) * 3) * 3;               // rotation (xyz)
+
+	uint32_t size = 0;
+
+	size += numJoints * singleJointFrameSize;
+
+	return size;
+}
+
+#endif
diff --git a/src/geometry/triangle.h b/src/geometry/triangle.h
new file mode 100644
index 0000000..2c31db8
--- /dev/null
+++ b/src/geometry/triangle.h
@@ -0,0 +1,30 @@
+#ifndef __GEOMETRY_TRIANGLE_H_INCLUDED__
+#define __GEOMETRY_TRIANGLE_H_INCLUDED__
+
+#include "../common.h"
+#include "vector2.h"
+#include "vector3.h"
+
+struct Triangle
+{
+	uint32_t vertices[3];
+	uint32_t groupIndex;
+	Vector3 normals[3];
+	Vector2 texCoords[2];
+
+	uint32_t GetSize() const;
+};
+
+inline uint32_t Triangle::GetSize() const
+{
+	uint32_t size = 0;
+
+	size += sizeof(uint32_t) * 3;      // vertices (index)
+	size += sizeof(uint32_t);          // group index
+	size += (sizeof(float) * 3) * 3;   // normals (xyz)
+	size += (sizeof(float) * 3) * 2;   // texcoords (uv)
+
+	return size;
+}
+
+#endif