I have made this from exercise U1-2 of 2nd chapter of URDF. I have placed the code below. The model with all the values used in the code being same but there is still the model coming out to be different.
<?xml version="1.0"?><link name = "base_link">
<visual>
<material name = "grey">
<color rgba = "0.75 0.75 0.75 1"/>
</material>
<origin rpy = "0 0 0" xyz = "0 0 0"/>
<geometry>
<cylinder radius = "0.06" length = "0.09"/>
</geometry>
</visual>
</link>
<link name = "roll_M1_link">
<visual>
<material name = "red">
<color rgba = "0.8 0 0 1"/>
</material>
<origin rpy = "0 0 0" xyz = "0 0 0"/>
<geometry>
<cylinder radius = "0.01" length = "0.005"/>
</geometry>
</visual>
</link>
<joint name = "roll_joint" type = "revolute">
<parent link = "base_link"/>
<child link = "roll_M1_link"/>
<origin xyz = "0.0023 0 -0.0005" rpy = "0 0 0"/>
<limit lower = "-0.2" upper = "0.2" effort = "0.1" velocity = "0.005"/>
<axis xyz = "1 0 0"/>
</joint>
<link name = "pitch_M2_link">
<visual>
<material name = "green">
<color rgba = "0 0.8 0 1"/>
</material>
<origin rpy = "0 0 0" xyz = "0 0 0"/>
<geometry>
<cylinder radius = "0.01" length = "0.005"/>
</geometry>
</visual>
</link>
<joint name = "pitch_joint" type = "revolute">
<parent link = "roll_M1_link"/>
<child link = "pitch_M2_link"/>
<origin xyz = "0 0 0" rpy = "0 -1.5708 0"/>
<limit lower = "0" upper = "0.44" effort = "0.1" velocity = "0.005"/>
<axis xyz = "0 1 0"/>
</joint>
<link name = "yaw_M3_link">
<visual>
<material name = "blue">
<color rgba = "0 0 0.8 1"/>
</material>
<origin rpy = "0 0 0" xyz = "0 0 0"/>
<geometry>
<cylinder radius = "0.01" length = "0.005"/>
</geometry>
</visual>
</link>
<joint name = "yaw_joint" type = "revolute">
<parent link = "pitch_M2_link"/>
<child link = "yaw_M3_link"/>
<origin xyz = "0.01 0 0" rpy = "0 1.5708 0"/>
<limit effort = "0.1" velocity = "0.01"/>
<axis xyz = "0 0 1"/>
</joint>
<link name = "head_link">
<visual>
<material name = "white">
<color rgba = "1 1 1 1"/>
</material>
<origin rpy = "0 0 0" xyz = "0 0 0"/>
<geometry>
<sphere radius = "0.06"/>
</geometry>
</visual>
</link>
<joint name = "base_head_joint" type = "fixed">
<parent link = "yaw_M3_link"/>
<child link = "head_link"/>
<origin xyz = "0 0 0.06" rpy = "0 0 0"/>
</joint>
<link name = "left_eye_link">
<visual>
<material name = "black">
<color rgba = "0 0 0 1"/>
</material>
<origin rpy = "0 0 0" xyz = "0 0 0"/>
<geometry>
<cylinder radius = "0.00525" length = "0.00525"/>
</geometry>
</visual>
</link>
<link name = "right_eye_link">
<visual>
<material name = "black">
<color rgba = "0 0 0 1"/>
</material>
<origin rpy = "0 0 0" xyz = "0 0 0"/>
<geometry>
<cylinder radius = "0.00525" length = "0.00525"/>
</geometry>
</visual>
</link>
<joint name = "head_left_eye_joint" type = "fixed">
<parent link = "head_link"/>
<child link = "left_eye_link"/>
<origin xyz = "0.0095 0.057 0.0085" rpy = "-1.5708 0 0"/>
</joint>
<joint name = "head_right_eye_joint" type = "fixed">
<parent link = "head_link"/>
<child link = "right_eye_link"/>
<origin xyz = "-0.0095 0.057 0.0085" rpy = "-1.5708 0 0"/>
</joint>
<link name = "camera_link">
<visual>
<material name = "green">
<color rgba = "0 0.8 0 1"/>
</material>
<origin rpy = "0 0 0" xyz = "0 0 0"/>
<geometry>
<box size = "0.0005 0.0005 0.0005"/>
</geometry>
</visual>
</link>
<joint name = "head_camera_joint" type = "fixed">
<parent link = "head_link"/>
<child link = "camera_link"/>
<origin xyz = "0 0.057 0.0255" rpy = "0 0 0"/>
</joint>