Celestia Forums

I'm trying to make two very small spacecraft (actually just Wheatley and Space Core from Portal 2) orbiting each other, with their barycenter orbiting the moon. I've so far tried two methods, both obsolete (I can't wrap my brain around the frames stuff that's recommended right now) and neither worked. The first try involved using a Barycenter definition, but I ended up with both cores at the center of the moon. The second try was something I remember seeing somewhere but can't remember exactly how it's done, something about having something that's black, high albedo, and invisible. Epic fail, the whole thing was gone, the barycenter, plus both cores. I can't find any tutorials on how to do this anywhere, and i think it's safe to say it's almost impossible.

The Barycenter and OrbitBarycenter keywords are usable only for Stars in STC files.
ReferencePoint is intended to be the equivalent of Barycenter in an SSC file.

When defining two objects revolving around a barycenter, it's easiest to start with their barycenter as an object itself. Then change the barycenter object's definition in some way to make it invisible. Each of the different ways of making an object invisible has different advantages.

-- add the prefix ReferencePoint to the barycenter's definition
-- inside the barycenter's definition add the keywords
Class "invisible"
-- give the barycenter object a Radius which makes it too small to see
-- use a Mesh which is completely transparent
With the latter two, you'll also have to specify a very low Albedo so that it doesn't glow when the viewpoint is distant from it.

Here's a starting point:


Here's a viewpoint to see them:

cel://Follow/Sol:Earth:Moon:object00/20 ... rc=0&ver=3

And here's what that looks like:

I'll leave it to you to try each of the different invisibility options.

Thanks, setting my barycenter object as class invisible helped. Here's a screenshot of the two in spaaaaaaaaaaace, both cores about 2 feet across. The blue one is Wheatley and the yellow one is the Space Core. I also added Rick and the Fact Core in their own orbits around Earth; I'll post screenshots of both later.