I’ve had a “dream” for a number of years now to model something in 3d, 3d print it, and cast it in metal. Based on the upgrade from my “flowerpot furnace” and the acquisition of new sand casting greensand, today was my first successful attempt (once again casting my companies logo). I’d previously tried my hand at some “lost PLA casting“, but the end results weren’t satisfactory. And honestly I’d give today’s attempt a C- : Being my first attempt, I had some flaws in my sand cast design, that resulted in defects in the end result. I also learned that if you want to pull off embossed letters like shown, you need to bevel them, or the sand will stick to them upon removal (which is what happened to the S & G) even if using parting dust. Regardless, the cleaned up results with some black paint added gives it a rustic \ worn look. Next attempt I’ll shoot for a solid B 😉
The print itself took about 2hr 15min on my Makerbot Replicator (1), using gray PLA, 200 micron resolution, printed on a glass build plate with blue painters tape. It’s about 13cm across, or just over 5”.
I finally decided to upgrade from my “flowerpot furnace” to something slightly larger, slightly faster, and quite a bit hotter: the “Model A furnace” from Lost & Foundry. Very pleased with it: Fired right up, and I had molten aluminum 15 minutes later. Next up, some real sand-casting.
I’ve made small games/apps in the past using Python/PyGame & Processing. When developing them, I’m always responsible for designing all the systems: And while a great learning experience, I only have a fixed amount of time to work on these side projects. So I thought I’d expand out and try a larger game development framework letting me focus on higher level concepts rather than the lower-level coding needed for basic systems.
The three big ones I’m aware of are Unreal (Epic), Cryengine (Crytek), and Unity. Nowadays you can download them all for free, which is fantastic. I’ve used Unreal & Cryengine professionally in the past, so I had interest in seeing how Unity worked. And one of the big deciding factors was the “scripting language” the engine uses: Unreal 4 has dropped their “UnrealScript” in favor of pure C++ (which I can read, but not really write), while Cryengine uses Lua (never touched it). Unity however supports C#, JavaScript, and Boo: C# is very similar to Java (Processing), which I am familiar with, so that made the decision pretty easy. And while arguments could be made for the “power” of a given engine, and my guess would be that Unity would be lower on the list, they can all do far more than I’ll ever need, so Unity was the choice.
And so far, I’ve been very pleased: Their documentation (user manual, component reference, script reference) and example tutorials/projects are fantastic . Easy to read, well spoken, and a breeze to follow. Plus, building the games and deploying to the web has been a snap. To date I’ve completed the two below ‘projects’, and I include a link to the completed game. While the ‘games’ are super simple, they were also super easy to make (thanks to the great tutorials):
Next I plan to go over their “Stealth” project next. And like the subject reads, it’s been fun: It’s nice to be in a development environment where it ‘makes sense’ and things ‘just work’. So far, my only complaint is they don’t have a build in interactive shell (REPL), and they should really add Python to their scripting language selection
Thought it would be fun to setup a time-lapse rig with my Raspberry Pi & it’s camera, having never tried that type of photography before. A bit of afternoon coding, and success:
11 hours compressed to 60 seconds.
This is what the camera-rig looks like:
Used some MircoRax to create a simple frame for the Pi & its camera.
Install dependencies
You can download my Python time-lapse code here. For the below examples, just stick it in your home (~) folder.
Executing the timelapse.py code is easy: It will create a /time-lapse subfolder where it will place all the jpgs. It doesn’t need any arguments to run: In that case, it will record for an hour, with enough images to make a one-minute long video at 30fps: It’s designed to take the guesswork out of trying to figure out how many frames to render at what interval based on the framerate. It handles it all for you behind the scenes. Plus it’s all configurable. To query the help:
$ python timelapse.py -h
usage: timelapse.py [-h] [-ct float] [-dur int] [-fps int] [-xres int]
[-yres int] [-q int] [-y int] [-m int] [-d int] [-hr int]
[-min int] [-s int]
Time for time-lapse! To start recording at a certain time, pass in any or all
of the time related args. If no time-related args are passed in, recording
will start immediately.
optional arguments:
-h, --help show this help message and exit
-ct float, --captureTime float
in HOURS, default 1.0
-dur int, --duration int
of final movie in SECOMDS, default 60
-fps int, --framesPerSecond int
of final movie (default 30)
-xres int, --Xresolution int
of image (default 1280)
-yres int, --Yresolution int
of image (default 720)
-q int, --quality int
of jpeg from 1-100 (default 85)
-y int, --year int ...to start recording
-m int, --month int ...to start recording
-d int, --day int ...to start recording
-hr int, --hour int ...to start recording
-min int, --minute int
...to start recording
-s int, --second int ...to start recording
So for example, to capture for 12 hours, and end up with a 1 minute long video:
python timelapse.py -ct 12.0 -dur 60
It also supports a delayed start, if you pass in any of the time values. For example, if you pass in an hour, it will wait for that hour to start recording. If you pass in a minute, it’ll wait for that minute of the current hour, etc. You can pass in any of the year, month, day, hour, minute, second, or none. If none, it starts capturing immediately.
Finally, I’ve learned that if you’re logging in via ssh, you should launch your code via nohup:
nohup python timelapse.py -ct 12.0 -dur 60
If you don’t do that, when you close the remote shell, it’ll kill the process, and no timelapse for you!
Make a movie
After you capture all the stills, how to make into a movie? The mencoder software can be used on the pi for that. I found a tutorial here that provides a solution. To install:
sudo apt-get install mencoder
First make a list of files from your /time-lapse folder (from the above tutorial link):
cd time-lapse
ls *.jpg > stills.txt
Then, to convert them into a movie with mencoder (modified version of the above example):
This will create a new avi file on the Pi. To get that moved to your PC, on Mac/Linux you can use scp (below example is my Pi’s IP, change it to match yours). Note, the below code is executed from your PC, not the Pi, and copies it to my Mac’s home folder:
Or you can use this great tutorial on how to use SFTP via FileZilla, if you’re more comfortable in a windowed environment.
Once I got my first movie copied over, I couldn’t play it (on my Mac) via the Quicktime player. However, my install of VLC opened it no problem. From there it was uploaded to YouTube: Done!
I’ve been experimenting with some backyard sand casting, and have had the desire to try and cast a 3d-printed object. I’d heard you can do a “lost PLA” cast, where the molten aluminum vaporizes the printed item, so I thought I’d give it a shot. Long story short: Works… sort of. This is my first try, so I didn’t really know what to expect, but the results were far less than I wanted: No detail in the object, and not all the PLA totally melted: I printed the object with only 5% infill and 1 shell (to generate as little material as possible). Regardless, it does make a good conversation piece 😉 In the future I’m going to get better sand (finer grain, better clay binder) to help preserve the detail, and probably try for a real lost-wax solution (3d print a mold for the wax), or a true sand-cast where I remove the item to be printed and simply fill the void with metal.
The end result is (an attempt at) the logo for the company I work for, Sledgehammer Games (a sledgehammer head seemed something worth forging):
A dime is next to it for scale
You can see on the left and right sides where I had to grind off the sprues.
Here’s a shot of my “flowerpot furnace” in action melting the aluminum for the project:
And one with the top removed, showing the red-hot crucible:
