The Roohr Way – Page 6 – There's a right way, a wrong way, and…

Estes and Escape Velocity’s Rocket Design

I first noticed while thumbing through old Estes ephemera on this site when I saw it staring me in the face:

Snippet from the 1990 estes catalog — 1990 Estes Catalog

Estes is a company that has, for a great many years, built and sold flying model rockets-as in, you build them, stick a solid fuel engine in the back, and launch it into the sky. It’s a good hobby for someone who’s a fan of spaceships. The same camp where I learned the art of model rocketry was where I found out about Escape Velocity, which brings us back to the point. If you’re an Escape Velocity or EV Nova fan, you probably recognize that as fictional space pirate “escort Frigate” the Atinoda Kestrel.

A diagram of the Kestrel, with labels for flavor — The Kestrel

Probably the most iconic ship from that game, it made its way into EV Nova as a post-game bonus option and NAEV as its poster-ship. Matt Burch, author of Escape Velocity, had this to say in an Ambrosia Times interview:

Ambrosia Times: […] Is it true that some of the graphics in EV are the result of a model rocketry hobby?

Matt Burch: Well, I used to build model rockets when I was little, and a couple of the ship designs in EV are loosely based on my memories of some of my favorite Estes kits.

That confirms my suspicions. So, which other ships are based on Estes rockets?

From the 1990 catalog, we’ve got these two:

Cropped catalog page of an oddly configured two-finned rocket — Estes Star Seeker

EV graphic from Evula.com — EV’s Executive Transport

Clipping from Estes catalog — Estes Strike Fighter

EV graphic of the lightning — EV’s Lightning Fighter

I’d seen the Rebel Cruiser described as having “babylon 5 roots” but I think its lineage is very clear from this:

Screen from a 90s Estes catalog — Estes Starseeker

I’m less sure about the Clipper (which I think is the astro blaster.) The configuration is the same (two back-swept wings with giant winglets and canards in the front.)

Astro Blaster from the 92 catalogue — Estes Astro Blaster

Screen from Escape Velocity — Clipper from Escape Velocity

There are two possibilities for the Manta, and I’m not sure which one it really is, despite it sharing the name with one of the rockets. Maybe a combination of both:

Manta from 1994 Estes Catalog — Estes Manta (’94)

So, several of the ships in EV share more than a passing resemblance to Estes rockets. There may be others that I’ve missed, or other sources of inspiration. I’d love to hear about them!

Making a model for FlyThroughSpace part 2: Export

Note: This post is way out of date, expect a new one soonish.

Apply the mirror modifier

Hit apply on your mirror modifier. Be careful: further changes will not conserve our precious symmetry! I advise that from this point forward you refrain from saving your work, or at least save it in a separate file.

Rotate the model

We’re going to do the rotation using hotkeys. This makes it easier since you’ll need to do this for every model.

'R' (rotate) '9' '0' (ninty degrees) 'X' (along the Y axis) 'CTRL'+'A' (Apply)

Then another transform:

'R180Y' 'CTRL' + A

Export

Next you need to install the babylonjs exporter. There are instructions here. Then export the scene. .babylon is a JSON format, so you can now hand-edit anything you’d like into it, such as the proper texture file. Note that on my machine the exporter crashes Blender but does do the export.

Making a model for FlyThrough.Space

Ever wanted to make a 3d vehicle model?

What follows is an extremely minimal (and probably very wrong) blender tutorial. I’m mostly posting this so that I do not forget, but I know that there’s an audience out there that just wants to use Blender to do quick modelling tasks, and this is the shortest path I’ve found to achieve that goal. This post explains how to make and texture the model. A subsequent post will explain the aspects that are specific to BabylonJS (and, thus, FlyThroughSpace)

Step 1: Bilateral Symmetry

Most scifi spaceships are bilaterally symmetrical, at least from the outside. I won’t get into for the rationale for this (if nothing else, cars and airplanes count.) And though there are Notable Exceptions, even those generally start from a symmetrical base with variations on each side.

We don’t want to have to recreate every change by hand, so we’re going to set up our blender object to automatically mirror our changes along the X axis.

Switch the “active data to display and edit” tab on the right to Modifiers (Wrench icon)

Now, add a modifier of the type “mirror” by opening the “Add Modifier” dropdown and selecting “Mirror”

One thing I notice here is that it offers up what I think is the equivalent Python code so that you don’t need to do this task in the GUI. A laudable goal.

Now select the following options and don’t hit apply.

Axis: Y, Options: Merge, Clipping, Vertex Groups

What follows is my least favourite step, because I’m 100% sure I’m doing it wrong. Your cube is half-repeated, because it was already symmetrical and repeated along the Y axis. You need to get rid of the real part overlapping with the mirror part. What I do is go to edit mode, set the selection mode to face, and then slide the face out of the mirrored side, then delete it. I encourage finding a more reliable method and leave it as an exercise to the reader.

At the end of this step, you should have half of a cube mirrored to make a full cube.

Half a cube reflected into a full cube

Step 2: Make your spaceship

I won’t claim to be an expert in actually using the modeling tools in Blender. When I first tried my hand at making 3d objects, it was in Lightwave, when your basic tools where Extrude and Slice, so that’s what I usually use to achieve the shapes I’m looking for. There are probably far better tutorials on how to actually model in blender out there, so feel free to consult some of those. I’ll be here, extruding faces and sliding edges around until you’re back.

Not especially spaceship-y yet

Some subdivision and the knife tool go a long way

You can press ‘K’ to select the knife too, drag it around to add vertices and edges in the middle of faces. You can delete troublesome vertices and re-close your mesh by selecting three vertices and hitting ‘F’ for a new face. I won’t pretend to be an especially good modeler. Here are the results:

Step 3: Paint on a texture

Use the circle select in edit mode (faces) to select every face. You’ll need to rotate the model between uses of the select tool to get all of them. Now in “shading/UVs” press “unwrap” and select “Smart UV Project.” Now you can switch your bottom window to “UV Editor” mode and scale it up a bit (icon in the bottom left)

Now make a material for it, set the view mode to texture or material, and load up some random texture to paint on.

ugly tiger looking thing

Well, that wasn’t very good. There used to be a way to just paint a single color and I was going to sort of airbrush it up, but I can’t find it anymore (leave a comment if you know where it is!) If you _must_ work with solid colors, you can texture paint from solid colored textures I guess.

If you haven’t saved your work before, do save it now and do not keep saving it after this step! We’re going to do some destructive editing in order to export for BabylonJS

In Appreciation: Termux

I’ve been playing with Termux quite a bit in the last couple of days. Being able to do development-any development-while standing on the train is an awesome feeling. I think the site undersells what it is-it’s your compiler in your pocket. It’s ssh in your pocket. I’m redoing my website on my phone (the mobile experience is crap at the moment) by editing the sources in vim, then hosting it locally with Python.

Beware of side effects on default arguments

Check out this quick interactive session:

Python 2.7.12 (default, Jul  1 2016, 15:12:24) 
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> def f(y, x={}):
...   print x
...   if y:
...     x['y'] = True
... 
>>> f(False)
{}
>>> f(False, {'x': True})
{'x': True}
>>> f(True, {'x': True})
{'x': True}
>>> f(False)
{}
>>> f(True)
{}
>>> f(False)
{'y': True}
>>> f(True, {'x': True})
{'x': True}
>>> f(False)
{'y': True}

What’s wrong with this picture? Notice that when I call f(True) we assign something to the default argument x. When we call f again, it replaces the default x = {} with the previous value of x!

I suppose the moral of the story here is that in order to avoid side effects, you should not mess with arguments you’re passing in, even if they’re just the default arguments.

Python list comprehensions

If, like me, you learned python and programming at the same time, you may have missed out on advanced features that, while awesome in python, won’t carry over to other languages you’ll “graduate” to using. One of these features is a list comprehension. It lets you in a compact (and readable) way write loops that take a list and return a list, and does not require lambda syntax. They let you write this:

list_squared = []
for x in [1, 2, 3, 4, 5]:
    list_squared.append(x ** 2)

like this:

[x ** 2 for x in [1, 2, 3, 4, 5]]

This really shines when you’re transforming and extracting data – you can also stick an ‘if’ at the end, turning this:

odds_squared = []
for x in [1, 2, 3, 4, 5]:
    if x % 2:
        odds_squared.append(x ** 2)

into this

[x ** 2 for x in [1, 2, 3, 4, 5] if x % 2]

It might not be a huge improvement in amount of code (or LOC, since you’ll want to break complex list comprehensions across multiple lines) but it saves you from potential mistakes, typing ‘append’, and (importantly) having to declare and use another variable name. I consider that a win.

If you found this post exciting, generator expressions will blow your mind.