Introduction: Making of a Simple Robot With 3D Modeling
The idea for this project started when I was studying and given an assignment with the brief called titled "articulation". The idea was to create an object that demonstrated articulation (movement and joints) using a 3D printer. I decide to create something fun and the idea of a toy figuring blossomed.
You will find that a lot of the process that I have used are repetitive, however this is deliberate. The construction process is simple and its a good way to get used to the basic tools and method. The key principle to remember is: Extrude equals (+) and subtract equals (-). The following steps shall provide you with a more detail overview on the kind of modeling methods I am using.
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Now continuing on.....step1
In this project the application I am using is Rhino. However the technique and tools used here can be found in most solid modeling packages such as Inventor, Solidworks, Vectorworks, Sketchup and 123D. (Be aware that Surface base modeling application such as Maya, 3DSMax, Blender may not work well with this modeling workflow and result may vary).
Modeling process break down:
The core techniques that is used here is Sketch (2DOutline), Extrusion and Subtraction (Cut or Different).
Sketch is a basic 2D outline of the shape you intend to create. So in this project the 2D Sketch/Outline is a circle shape (fig I,II). When a Sketch is drawn it sit on an X,Y,Z axis in 3D space to make this easy to understand we can think of this as looking at it from the Top, Front and Side view.
In (fig I) you can see we are looking at the circle from the top view and in (fig II) the view is adjusted to a 3D angle to provide depth and perspective of the view this help us view the 2DSketch of the circle as it sits in a 3D space. Now a second smaller circle is drawn (fig III) making sure that the second 2Dsketch is drawn from the view the initial circle was drawn in Top, Front , side and not in any other view as this may distort the result.
After this we can adjust the view back to the 3D perceptive angle to begin modeling. (fig IV)
Extruding is basically adding volume to the 2Dsketch, In (fig IV) the outer circle is selected indicated by yellow. When extruding you control the height of the extrusion by freehand via mouse control or enter a specific height via a dialogue box. The height entered here is 4mm. (Depending on the software this dialogue box could be a pop up, inside a drop down menu or a menu box, etc)
In (fig VI) the smaller circle is selected and extruded which results in a smaller cylinder (fig VII) and the mouse was used to control the height. When both circle 2Dsketch are extruded the result well look like (fig VIII) the 2 parts are still independent of each other and can still be moved around and adjusted.
Subtract (Cut, Different) are the same process. As the name indicates when a subtract is used it is removing one part from another. In (Fig IX) part A yellow selection is first picked then part B is selected. By selecting the Subtract (Cut, Different) tool, (part B) well be subtract from (part A) resulting in (fig X). So the parts that is picked first (part A) will remain and the parts that is picked second
(part B) well be subtracted this includes area of (part A) that intersect (part B).
In (fig XI) the larger cylinder is selected first (part A) and the smaller cylinder (part B) is picked second. By using the Subtract (Cut, Different) tool the result well look like (fig XII). we can see that the smaller cylinder (part B) is subtracted including area of (part A) the intersect (part B) resulting in a hole.
Step 2: Body and Head
To create the body I begin by setting up the dimensions by drawing the rectangular outline sketch.
Once the sketch is set and the form is extruded (rectangular block). Now I draw a second smaller rectangular outline and extrude it. I used the small rectangular block to subtract out the connection space.
Next I sketch out a circle at the center of the connection space and extrude it.
The resulting cylindrical tube is then subtracted to create hole at the connection center. well late be used to build a hinge connection
Next the lower front corners are cut at and angle. (This allow the hinge area to bend further when assemble)
The final part of this stage is to add the head. Which is a simple sketched of a circle that is extrude to form a cylinder.
Step 3: Waist and Arm
Constructing the waist
To begin the waist I sketch out all the parts outline in advance and then I begin extruding the parts.
The first extrusion is the large rectangle outline.
This is followed by the three small rectangular parts. The two longer length rectangular blocks position are then adjusted to a lower position.
The long rectangular block are subtracted to create the gaps for the connection space. The small circle at the center is then extruded to form a cylinder. The cylinder is then subtracted to create the hole. The top corner of the rectangular block is fillet to create the curve shape.
Once the base construction is done the body and the waist can be align together. As you can see the the waist part will sit in-between the connection space of the body. The hole of the body and waist connection can be used to align the two parts.
The arm is created in the same way as the body and waist. The outline of the arm is drawn and extruded. A hole is made for connecting the arm to the body. The connection space between the lower and upper arm is cut out as well.
To create the lower arm I duplicate the the upper arm and adjust it by moving it down.
Now I begin to shape out the lower arm by sketching outline to be extruded and subtracted to form the hinge this is the same waist. The hand is the result of a large and small circle being extruded. Followed by a small rectangular block being extruded at the center and then subtracted.
Finally to built the arm on the opposite side. I mirror them by selecting the whole arm and using the mirror tool to duplicate it to the opposite side.
Step 4: Building the Legs and Feet
The legs and feet follow the same process as the arm gives a basic over view of the process.
First the upper/lower leg and feet outline are first sketched out. This is followed by extruding them and creating the leg and feet area (image1-3). The joint area are also sketched out and extruded (image 4). Holes are then made for the connecting area between the joint by sketching circle, extruding out the cylinders and then subtracting out the holes. A short cylinder is sketched and extruded to fit in between the leg and feet joint. After this the leg and feet are shaped out by filleting their corners to allow them to bend. When completed the legs are mirrored to the other side.
Step 5: Assembley and Refinement
Finally the part are all assembled and refining the form can take place. The torso was a little large so I made some minor adjustments by cutting it down and readjusting the arms. Once I am satisfied with the shape I export it out as an .STL (binary) file and set it to the 3D printer. The two digital rendering show the digital result and the last image show the finished 3D printed result. Turning concepts into reality!
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