My first 3D print ever, and no margin of error.
I designed a basic car that has a name cut out from the top prifile. The name, you ask? It's my niece's (Sunny). The car, you wonder? It's roughly based on a 1967 Porsche 912. Very roughly based. The occasion, you question? Sunny's birthday tomorrow. The margin of error? If I screw this up, I'll look like an idiot- being her only uncle and having nothing to give Sunny at her birthday party.** To add even more difficulty to the issue, this is my first 3D print, ever; I'm flying in blind and hoping for a perfect strike.
I think it's important to note - as I'm writing this right now I'm watching the 3D printer do its thing; the feeling is difficult to describe. I've spent hours and hours making something [virtually], and to see the embodiment of the item that I've created is beyond thrilling. It's almost magic - I started with nothing, before my eyes a translucent green form that I conceived and designed is taking shape. It's really cool. Really cool.
At this juncture I want to note that I can expand on any one of these steps. Each of the steps in this instructable could be turned into an essay in and of itself; but I'm not going to write a whole bunch of stuff not knowing if anyone even wants all of the fine details. If there are questions, don't hesitate to ask, I'm happy to be more descriptive if there are wondering minds out there!
**Both Sunny and her parents/my siblings are awesome - it wouldn't be much of a deal if I don't bring anything, I guess the stress/low margin of error is self imposed!
Step 1: Design the car
Designing the car took me 3 days, almost non-stop. I was using SolidWorks, which is both sophisticated and intuitive (and I've modeled other things in), but I based the model on a feature that I've never used before (surface loft). I kid you not, I "built" between 5 and 10 Porsche 912s before getting it right, with each model taking me between 2 and 5 hours. Pictured are a few of my attempts.
Some hints that I learned the hard way:
Most important: start with a basic shape, then add more features! 3 or 4 times I spent hours on a design, but then the surfaces failed to render, for various (still unknown) reasons. It was MUCH easier to start with a very basic shape, make sure that the surface loft worked, and then add detail (via adding additional cross sectional sketches). It's MUCH easier to add more detail to a surface loft than to have all kinds of details [cross sections], only to find out that SolidWorks can't render those details.
Use control polygons for splined curves. This'll make your life much easier when you're trying to edit/modify a complex curve.
Make sure that all of the points are BOTH coincident AND pierced when you are intersecting a cross sectional line with a longininudal curve. Especially if you mirror points over a line, those mirrored points WILL NOT pierce the mirrored line if you use the middle of the cross section as the mirroring entity.
The less cross sectional guide curves the better. In some of the early models, I had around 10 cross sections, but the model/surface loft didn't work out or looked stupid. I won't tolerate a stupid looking model for my only niece. Rather than trying to modify each model so that it was sufficient, I just started over, which I think was the right decision (it's more difficult to fix faulty things than to start from scratch). With more cross-sectional sketches that SolidWorks tries to knit together, the more the program can get confused. I ended up using 4 cross sectional sketches, the outline of the car, and the longitudinal middle cross section of the car (running bumper to bumper). The fewer the lines/splines that Solidworks has to combine to make a surface, the cleaner the surfce (in my limited experience).
For whatever reason, it DIDN'T work for me to sketch the front and rear face of the car. I ended up just lofting the appropriate curves to the appropriate planes. This fact frustrated me to no end, and I probably spent the better part of 4 hours trying to remedy this, but for whatever reason SolidWorks liked it when I drew the centerline of the car, then drew ONE outside line (the bottom of the passengers side, or the bottom of the driver's side) and mirrored it over the drawn centerline, along with half of each of the 4 cross sections.
NOTE: I am far from a Solidworks pro - I'm sure that there are people who will tell you something different than what I did, and they could probably do it better. Good for them. I'm just saying what worked for me.