Category: demo

Birthday Cake & Orbital Material | The Ron & Way Show

Your favorite Open Source Sorcerers are at it again!

We take a dive into the birthday cake model I worked on for use in the planetarium, and we get to explore Ron’s delightfully clever way of using shader nodes to display a fading orbital trail.

Be sure to hit the Like button, and please do subscribe to both of our channels while you’re there.

The birthday cake was shown in the previous post along with a link to the blend file.

The Ron and Way Show

Part of my return to sharing FOSS-y goodness online is thanks to my good friend Ron Proctor.

Ron invited me to hang out and make some YouTube videos and I’ve been having a great time. Here is our latest:

The UV dome is in my previous post here on FOSSdome, and here is the cute little galaxy I just made with Ron’s script and node setup:

swirly blue dots

A Very Fishy UV Map

Generating a hemisphere model in Blender with properly spaced UVs for fisheye dome masters.

UVs are texture coordinates. An image plane 3D model would be measured in X and Y coordinates. The image texture applied to that model would be measures in U and V coordinates.

I frequently need to apply fisheye images to a virtual dome within Blender. Sometimes I’m prototyping, sometimes I’m building a scene with a dome in it, sometimes I’m splitting the dome into parts for special effects in the planetarium.

The quickest way has always been to create a UV Sphere and delete the bottom half.

Orange wireframe sphere wireframe sphere, bottom half orange

This results in a nice looking hemisphere, but we can’t apply a fisheye, since the UV map is half of what was created for the full sphere..

wireframe rectangle on left, wireframe hemisphere on right

Applying an image to the map yields a fun result, but not what we want..

Abstract image within a circle

Of course, a new UV map is required:

By unwrapping the hemisphere model, we can create a closer UV map..

But the rings toward the edges get closer together, and this causes distortion at the edges of the hemisphere..

After giving up on getting Gemini to help me extract a proper map from a UV hemisphere, I asked Gemini to write me a python script with 3 parts:

  1. Create a flat circle with equally spaced rings
  2. Unwrap the model to get a lovely UV map
  3. Reposition the vertices of the circle to form the hemisphere.

It worked! And just look at the spacing on this lovely UV map…

And the same image texture applied.. just look at those edges, they are true!

The script can be downloaded here: UV_Dome_Generator_for_Good_UVmap.py

For the script, example blend file, an exported fbx model, and summaries of the method and the several wrong turns it took before I thought to make a circle first, go to https://github.com/waystar/Blender-UV-dome-generator.

JunoCam Citizen Science

My first attempt at Citizen Science on display in the dome!

A few weeks ago, I watched this video, produced by the Griffith Observatory a year ago:

As in the demonstration video I watched, I used Gimp. Of course I could have used Krita, but Gimp is my go-to since I’m so familiar with it.

First I downloaded set of images from 2021-07-21 Perijove 35:

https://www.missionjuno.swri.edu/junocam/processing?id=11074

I opened the three color PNGs as layers and colorized them accordingly.

Then I played around with the individual layers’ brightness and contrast settings, then combined using Screen as the blend mode.

After I got the colors close to how I liked them, I used the G’Mic Tone Sharpening to bring out the detail.  (https://gmic.eu/index.html)

Before tone sharpening
After tone sharpening

I spent very little time on it, about 25 minutes total. I’m pleased with it and look forward to showing others how to make their own.

Fun with Blender and Mars

Had a bit of fun making videos to celebrate in the weeks leading up to the Mars Perseverance landing. This one was one of my favorites.

Links from the video:

Blender http://www.blender.org​

Blender HiRISE DTM Importer http://github.com/phaseIV/Blender-Hir…​

HiRISE DTM Quickstart http://www.uahirise.org/dtm/howto.php​

Terrain model data http://www.uahirise.org/dtm/dtm.php?I…​

Mars Perseverance Mission http://mars.nasa.gov/mars2020/

Stellarium remote fun

I LOVE open source software! 

Stellarium sky

Stellarium is one of the top open source software packages for desktop sky viewing. Since I won’t be presenting shows in a physical planetarium any time soon, I figured I should work out how to present better online.

Stellarium has a remote web interface plugin that is pretty easy to set up.  So I’m using my giant monitor for presentation and my little monitor for controls and for programming.

I’m clumsy with the on-screen menus, so having them on a separate monitor is great! Some actions take a while to set up, so I tried a little scripting to automate some stuff.
And then I decided that rather than hunting through pull-down menus for my little scripts I should make some buttons for scripts and actions.
So I started modifying the html. 
And relied on the kindness of a stranger’s blog post to expose the functionality.
Thankfully I found an Atom package to make that json readable.
I don’t often spend enough time in any given language to get good at it. But in this effort, I’m digging into Stellarium scripting/javascript, html, and to find the right language for scripting actions I found myself searching the source code for the project itself.

Fractal Flames a happy mistake

I used a flame that I generated in Gimp, then converted it to the XML format using flam3-convert, then used defaults with flam3-generate and rendered with flam3-render.
I’m working on a workflow to generate some for dome use, but not random defaults.
Oh yes, I didn’t apply any processing, just strung the frames together. 

Fulldome Blender 2.8 Workshop GLPA 2019

The 2019 annual meeting of the Great Lakes Planetarium Association was held last week, hosted by the Ritter Planetarium of The University of Toledo.

It was special for me because my planetarium career started at Ritter Planetarium in February 1992. Honestly I had planned to stop conducting workshops for a few years so that I could concentrate on my GLPA executive community duties. But Alex Mak asked so of course I said yes.

The result is a very revised version *NEW!* for Blender 2.8:

https://github.com/waystar/2019-Blender-Workshop-Materials

  • Setting up render engine, camera and outputs for fulldome masters.
  • Setting up layers to separate objects for compositing to get glows or denoising only on some objects.
  • Compositing node setups examples.
  • Basics of materials, with shader node tree examples for incorporating alpha channels and animating fades between textures.
  • World environment settings and node trees for animation.
  • Examples of animating various objects and effects achieved through animating modifiers.

https://github.com/waystar/2019-Blender-Workshop-Materials

Click the “Clone or download” button to download the whole thing in a zip file.

Drop me a line if you find mistakes or OS-related differences. (I test on Linux and Windows.) Also, let me know if you find any of it particularly useful and I would LOVE to see what you make.

And of course, if you are having trouble with something in particular that you are trying to do, let me know. If I can’t help get it to work, I might be able to suggest alternate approaches to get the same effect.