In Part 2 of this Instructable I cover how to build the table quickly using 123D Make.
By following this Instructable you should be able to quickly design tables and other similar objects with whatever dimensions and looks you'd like.
-A computer (Mac or PC)
-123D Design (Download it here) [NOTE: The online and iPad versions have significantly fewer editing abilities, so you won't be able to complete this instructable without installing the "desktop" version. Sorry.]
-If you're using a laptop you'll probably want a mouse
[If you already know some CAD, feel free to skip over reading this next part.]
This Instructable is also an introduction to CAD (which stands for Computer Aided Design). CAD is the basic name for any computer program used for creating representations of physical objects. In the professional world CAD is used for designing airplanes, skyscrapers, blockbuster movies, and nearly anything else you can think of. We're not going to create anything nearly so complex, but using this tool you can begin to design and eventually build intricate and attractive real-life objects.
Step 1: Which Way Will It Stand?
[For new CAD folks: there are many ways to create objects. Perhaps the most fundamental ones is to create what are known as sketches (2D closed shapes) and then do operations on them (e.g. Pull or "extrude" it straight out into the 3rd dimension, "rotate" it around an axis to create an axially symmetric object like a doughnut or axle, "sweep" it along a predefined path, etc.). In this Instructable I'll show you how to make a relatively complex sketch and rotate it to make the design you see in the intro.]
[For folks with previous CAD experience: Just as a heads up, 123D Design is not a history-based modeler, which can be pretty different. Super well defined and constrained sketches are harder to do, but by playing around you can pretty quickly figure out some other ways to do what you're used to doing in professional level CAD. For instance, once you add a filet the dimensions will disappear, but you can later use the "Press/Pull" command to change the radius to what you need.]
My favorite way to select where to place my sketches is to create a cube and use the sides as planes on which to draw my sketches. Adding a cube is super easy in Design; simply select hover over the "Primitives" drop-down at the top of the screen and click on the cube button. You can scale this cube to whatever size you want, but for this Instructable I'll just use the default cube and place it anywhere on the existing plane.
To be clear, you could use the final real-life scale for each of these steps, but for this Instructable I made my table at a small scale, just to get the look right (I re-scale it in the second part of the Instructable to get it to the eventual size I want). It may be better to do it to scale at first, but I was being lazy. So it goes.
By the way, as you go about using the program you may notice some small text show up below your cursor. These are step-by-step tips that will help you understand how to use the tools in the program. Paying attention to them can be quite useful.
Step 2: Start a Sketch
Step 3: Make a Spline
[Note: 123D Design automatically snaps points to grid vertices if you get close enough to them. I find this helps get dimensions more exact without having to dimension things. The grid also resizes as you zoom in and out, so you can use this to get the points to exactly where you want.]
Step 4: Finish the Sketch
When you've done that, start drawing your lines as shown to complete the sketch (meaning you'll end up with a closed shape that turns yellow). Just so you know, you don't need to draw lines horizontally and vertically, and can select lengths and angles by just typing them while drawing a line. However, in this case we'll just finish the sketch up using horizontal and vertical lines so the table will have a flat top and bottom.
Step 5: Make It Solid
Once you've deleted the cube you'll be left with just a sketch, standing up from the ground plane. Now we can use the "Revolve" command to make it into a solid object. You can find the "Revolve" command under the "Construct" drop-down (it looks like a box with a plus sign and a pencil). To revolve the program needs three pieces of information: first, it needs the closed sketch to revolve, and second, it needs an axis to revolve around, and the third is how far around to create the solid. We tell it this by first clicking on the sketch, and then clicking on the vertical line of the sketch, and finally, we tell how far to revolve by either dragging the handle or entering an angle in the dialog box.
For this example I revolved the sketch -180 degrees, so the flat face of the finished object is facing us. The reason for not revolving it the entire way around to allow us to easily access the sketch, which we'll use to hollow out the form in the next two steps.
Step 6: Hollow Out the Table
First, go back to the view of the flat face of the half table. Now, we use the "Move" command to move the sketch over by how thick we want the walls to be. You can do this by dragging the handle as far as you need, or grabbing the handle and typing in the distance in the dialog box.
Once you have moved the sketch the proper distance you want to drag the vertical line towards the spline so that it is on the other side of the central axis of the table. [This is because the program cannot do a revolve command that results in a self-intersecting cut or solid. This concept is a bit confusing, but basically a cut or solid is not allowed to run into itself during the operation. This means that you are never allowed to revolve a sketch around an axis that intersects it.] You can drag the vertical line by clicking on it with no commands active and dragging it to where you need.
Once you have dragged the vertical line it is time to create an axis of rotation. To do this you simply draw a line using the "Polyline" command down the middle of the face of the table. This should be a separate sketch (meaning you should start the sketch by clicking on the face of the table and not the yellow sketch). Make sure that the axis is exactly in the middle of the table or you will end up with a lopsided table, which isn't really what we're trying to do.
After this, you will use a "Revolve" command on the yellow sketch, and the axis you just made. You want to use this to cut out a swept section all the way through the solid. Again, you can do this by dragging the control through the part, or by entering -180 degrees in the dialog box. When you are done, hit "Enter" to finish the cut. [NOTE: 123D assumes that revolving (or extruding, sweeping, etc.) a sketch through an existing solid means you want to cut out that section. You can change this behavior in the box, but here we do want a cut, so we will leave it as is.]
Finally, you will select the entire central section that is left (not just a face of it) and delete it by hitting "Delete" or "Backspace." When you're done you may want to get rid of the sketch by either deleting it or by hovering over the eye icon in the top right and then selecting the "hide sketches" option.
Step 7: Mirror Your Model
Step 8: (Optional) Tweak Your Table
To change the aspect ratio of your table select the "Scale" command from the "Transform" drop-down. Make sure you use the drop down command to select the "Non Uniform" option. Then you can drag one of the three handles to scale your table in that direction. [Note: you can also select the "Scale" command by clicking on an object and using the gear-shaped drop-down.]
Thanks for reading my Instructable. I hope it's helpful.
Now onto the assembly!