Modeling of mechanical objects in blender is a great way to improve your modeling and rigging skills and is often easier than modeling purely organic ob-jects. In this tutorial, I will guide you through a high level approach to creating an anthropomorphic robot character called Robbie.
Reference Images and Sketches
I used several sources of inspiration when sketching Robbie, ranging from movies such as “Robots”, by Twentieth Century Fox to the almost limitless supply of images provided by Google. While the reference movies and images helped develop the sketches, I found small model robots, similar to what you may find in a estoy shop, the most useful for understanding how the various joints worked.
Figure shows the final sketch that I used as the basis for the model. While the sketch is quite basic and is posed differently to the final render, the essential characteristics and relative proportions should be clear to see.
One of the decisions that I made early on in the de-sign process was that Robbie would be a friendly looking robot and have certain human-like qualities.
It is for this reason that he has large eyes and his jaw was modeled to appear like he is smiling. Anatomically, he loosely matches that of a human, but you'll notice that his arms are disproportionate in size with his legs and body.
The reason for doing this was two fold, firstly I wanted to give him a bit more character and experi-ment with the idea of him being a robot. The second reason was to make future animation of the model easier as it's far more difficult to convincingly animate a model with exact human proportions.
Modeling the Skeleton Framework
The modeling process started with creating the ba-sic skeleton framework. While most of the skeleton would later be hidden from view, I used it as a guid when modeling the visible parts of Robbie and later in the rigging process.
Each component of the skeleton frame started off as a simple primitive object such as a UV-Sphere or cylinder. Placement of the ball and socket joints was achieved using Blender's "Snap Cursor to Object" and "Snap Object to Cursor" operations.
The ball and socket joints were created from a UV-Sphere with 12 segments and 12 rings [12,12].
The socket joint was modeled by selecting the third edge-loop [Alt-Right Mouse Button] as shown in figure 002, duplicating [Shift-D] it, separating [P] it from the parent object and then using a series of extrudes [E] and scaling operating [S, Shift+X] to create the tapered socket joint as shown in figure 003. Creases were added by placing loop-cuts [Ctrl-R] in close proximity to existing geometry. Smoothing was added to both the joints and sockets and a sub-surface modifier was added to the socket joint. After creating the first socket joint, it was then duplicated [Shift-D] and rotated [R] about the centre of the ball. Each ball and socket joint in the model is simply a scaled linked dupli-cate of these three objects. Using this simple ball and socket joint, together with open cylinders consisting of 12 segments, I created the skeleton frameworque as shown in figure 004.
Modeling the Head
I wanted Robbie to possess human-like characteristics and to look friendly. I therefore decided to give human-like eyes and modelled his jaw such that it appeared that he was smiling. The head started life as a UV-Sphere[12,12]. Half of the verti-ces were removed and a mirror-modifier about the x-axis was added.
I created the jaw by se-lecting the faces shown in figure 005, duplicated [Shift-D] and separated [P] them and extruded [E] the region. Addi-tional detail was added to the jaw by adding loop-cuts [Ctrl-R] around the axis of rota-tion as shown figure 006 and extruding [E] a face to re-semble a tooth.
I'm not not going to cover how to create Robbie's eyes in this tutorial as there are some great eye tutorials available on-line and in previous publications of Blender Art magazine.
I did however enhance the eyes by adding a bottom eyelid and placed a tapered cylinder above each to act as an eyebrow. When creating the eye socket, the aim is to create a realistic
hole in the mesh without generating ugly geometry. I was able to keep the mesh clean by deleting [X] one of the faces and selecting the resultant edge-loop [Alt-Right Mouse Button], snapping the cursor to object [Shift-S] and selecting "To Sphere" from the "Mesh Tools" menu.
The edge-loop was then scaled slightly to accommodate the eye as shown in figure.
Robbie's no sé was created using the bolt factory wizard located in the scripts menú. The default settings create a bolt with a lot of geometry, especially around the shaft of the bolt. As most of this will be hidden from view, I deleted it and replaced it
by extruding [E] the edge-loop where the shaft meets the head of the bolt.
The head was completed by adding a low-poly bolt to each side. The low-poly bolt was created from a UV-Sphere[12,12] where half of the sphere is de-leted and the largest edge-loop extruded and scaled in-wards. It was then extruded once more to form the cylindrical section of the bolt as shown in figure 008.
The slit in the top of the bolt was created by extruding [E] some of the faces inwards along their normals.
Modeling the Upper Body
The upper body started life as a cylinder with its ma-jor axis aligned along the z-axis. Once again, half of the vértices were removed and a mirror-modifier about the x-axis was added. A succession of loop-cuts [Ctrl-R] added along the length of the cylinder along with scal-ing [S,Shift-Z] formed the basis for the object. Once I was happy with the proportions along the z-axis and x-axis I switched to the side-view and scaled all the edge-loops except the ones at the top and bottom of the cylinder.
This improved the proportions of the upper body.
Creases were added as described earlier in this tutorial.
Once I was happy with the general geometry of the upper body I selected the upper section as shown in figure and separated it from the lower section. This would later allow me to place Robbie in a more natural pose by placing an arch in his back.
A plate was added around Robbie's nek to provide a little more detail to the model. This was complemented with a few low-poly bolts as used earlier on
Robbie's head. A close up of the plate is shown in figure.
Modeling the Lower Body
Robbie's lower body was created from a cube with one level of subdivisión [W] and all vértices with negative x or y coordinates deleted and a mirror-modifier added for both the x-axis and y-axis.
The cube was positioned as shown in figure and the base of the cube scaled [S,Shift-Z] inwards while being locked in the z-axis. A total of seven loop cuts were added to the cube to create the ge-ometry shown in figure 011. The lower body was
completed by adding four low-poly bolts, two to the front of the object and two to the rear.
If you look carefully at the bolts, you'll see that each has varying degrees of rotation to increase realism. The bolts not only help to complete the model but alos cre-ate some nice shadows during the render stage.
Modeling the Arms and Hand
The upper and lower arms were each created from a cylinder. Three edge loops [Ctrl-R] were added to the cylinder and scaled [S] outwards to add some definition and a smooth contour. Additional geometry was added to the upper-arm around the shoulder by selecting the six edges as shown in figure 012 and extrud-ing [E] them three times while tracing out a curved surface around the shoulder joint. Additional geometry was added to the lower arm in exactly the same way as shown in figure, but this time it was to protect the el-bow joint. Minor adjustments were made to the arm while viewing the model from various angles and finally a subsurface modifier was added to each object and smoothing applied to each of the faces.
Robbie's hands are based on a flattened Cube with two edge-loops [Ctrl-R] placed at the locations of each of his three fin-gers as shown in figure 014. Addi-tional geometry was extruded [E] from the side of the cube where the thumb would later be attached. The fingers and thumbs are each based on Robbie's arm skeleton, with an additional tapered cylinder added to each to form the finger tip. Each of the digits were attached to the hand and placed in a natural pose.
Modeling the Legs and Feet
The upper and lower parts of Robbie's legs were created in exactly the same way as Robbie's arms, actually, I du-plicated [Shift-D] the arms and tweaked each of the edge-loops to get the desired geometry. The only minor difference between the arms and legs is that the legs bends in the opposite direction to the arm and therefore it was necessary to rotate the lower section of the duplicated arm. A detailed view of the geometry of the Robbie's leg is shown in figure.
Moving on to the last part of the model, Robbie's feet. It should be of no surprise that each foot was created from a UVSphere [12,12] with half of the faces deleted [X] and additional faces added to form the sole of the foot.
A sub-surface modifier was then added along with an edge-loop around the base of the foot to create a solid crease and flat sole.
The foot was then scaled [S, Y] along the y-axis to elon-gate the foot and give Robbie greater stability. The toe-cap on each foot was created in a similar way to how I created Robbie's jaw. The faces shown in figure 016 were selected, duplicated [Shift-D], separated [P] and ex-truded [E] to create the new region. Additional edge-loops [Ctrl-R] were added to the toe-cap around the axis of rotation and finally sub-surface modifiers and smoothing was added to each part of the foot. As a fin-ishing touch, I added two low-poly bolts to each foot, one on either side of the foot to give the foot the same level of detail as Robbie's jaw.
The final step in the modeling process was to duplicate [Shift-D] all the objects on Robbie's left hand side and mirror them about the x-axis [Ctrl-M,X], while ensuring that the 3D cursor was located at the origin.
So there you have it, a high-level guide to creating an anthropomorphic robot character called Robbie using primitive geometrical objects in Blender.
For those of you interested in watching a series of video tutorials going through each of the stages outlined in this tutorial, as well as rigging, lighting, UV-mapping, texturing and composite rendering of Robbie, please subscribe to my Vimeo channel "Robbie The Robot" http://vimeo.com/danieljhand/channels