Alright, third post in a row where I switch to a new build system. I know it’s not a great look, but I swear this is the last time.
With this new model in Build123d, I’m finally settled on a library that seems to scale gracefully (roughly linearly) as assemblies accumulate complexity.
Why the switch?: Assemblies become unwieldy Previously I touched on the fluent programming style, and how it felt like a substantial change from the OOP style I’m used to.
In this latest update, ORNIS now supports element selection! This required a bit of re-thinking of how messages are handled in the front-end, but I’m quite happy with how it turned out. One of the downsides to working intermittently on a project is that one tends to run into a lot of “Wait, I’ve already solved this!”, and this update has a few of these instances. The big one was almost re-inventing “msg_tree”, essentially a nested tree data structure I created for the service interactions.
In the last post, I mentioned I was having reservations about OpenScad, and its suitability as CAD software for KIWI. The primary source of these reservations was simply that after making only minor headway, each operation had become so tedious. Simple things like a bracket for a servo was becoming far too much trial and error for my liking. Initially, I thought I’d be able to simply take some measurements of my part before I begin modelling, save them as variables “servo_width, servo_height” or something similar, then use these dimensions to define our extrusions/cuts for the servo mounts.
One of the earliest requirements I laid out for ORNIS was the ability to send/recieve service calls. While the ‘ros2 service’ interface may be convenient, it is cumbersome to say the least. I have had countless issues with attempting to fill out larger service requests via the CLI, only to accidently mess up the indentation. The resulting failure to request always strikes a nerve.
Ironically, my initial implementation of the service interaction had the exact same issue.
In our last post, we blocked out a primitive 3d model of our inverted pendulum. From here, the next step is to get the basic mesh into Gazebo, to allow us to begin testing in simulation.
From Zero to Gazebo I suspect that everyone who has ever used ROS has had to deal with the horror of building/installing ROS. It can become a serious pain, and you wouldn’t believe the number of hours I’ve had to spend in the past dealing with missing/incorrect dependencies, or the source code refusing to compile.
TUI’s have been around for years (Understatement). There is a strong precedent for them, with plenty of examples showcasing what makes for a great piece of software. I’ve always admired how much `prettiness’ a developer can achieve using simple symbols and glyphs. I really do feel that the limitations and constraints really force one to be creative and mindful of the medium in order to get something that is enjoyable to look at.
I’ve been wanting to get better about writing updates more frequently than I am currently. One of the big reasons for taking so long between posts is that I’m absolutely horrible at judging where exactly I should ‘plant the flag’ in a project, and get to writing about it. This is most evident in ORNIS, where I literally spent six months writing code, and didn’t write a single word about it until it was essentially a mvp.
Presenting ANOTHER entry in the “Definitely not a Backronym” series! This one is a bit different, being a project that is entirely software based.
TL:DR I made a Terminal User Interface for ROS2. Is it good? No. Should you use it? No. Go use Foxglove Studio, it’s an open source WebApp, made by people mature enough to know that Terminal User Interfaces are limiting and dumb. If you’re still interested, you can check out the GitLab here.
