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I want to show simple views of various solar system phenomena from the perspective of an observer on a crudely simulated Earth (basically a ball with some relief bumps as pseudo-mountains to provide some guide to rotations of the view, etc). The phenomena of interest are things like the tracks of the sun and moon at various latitudes/times of year, eclipses, and planetary motion. Somewhat unusually for a Blender question the graphical quality isn't important, instead I hope to get a high degree of automation. Taking the example of a sun track from dawn to dusk, I hope it's possible to place a camera on a bumpy globe, set the camera to point to the sun, and then simply rotate the globe (mountain bumps and camera included) - this seems a lot easier than using the API to slide the mountains and camera around the surface of a smooth globe. At the same time the other planets would be moving in their orbital paths (ideally ellipses, though for simple didactic work circles are probably good enough)

From my reading and (ignorant) playing with Blender I'm unsure whether this approach of forming a complex object (with attached camera) and then moving it is well within normal use or whether that's going to be an uphill struggle to use Blender in some other product's native domain (e.g. CAD/CAM). Part of my difficulty is that as a rank amateur I lack even the usual vocabulary so may be overlooking some clear guidance in the FAQ (etc).

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  • $\begingroup$ I can't see any problems you can not solve. Blender has some size limitations but those should be okay if you're fine with a 1 meter minimum movement. Also keep in mind, that the bumpy spheres (e.g. earth) won't have infinite resolution for performance reasons. $\endgroup$ – Leander Oct 3 '16 at 22:53
  • $\begingroup$ @Leander - that's reassuring. I don't think that resolution will matter (my basic concept of mountains are a few distinguishable polyhedra). Would the size limitations preclude a 1km-based scale (e.g. Earth diameter 13,000, sun distance 150,000,000, Saturn distance 1,600,000,000)? $\endgroup$ – Tom Goodfellow Oct 3 '16 at 23:16
  • $\begingroup$ The elliptic paths of the planets aren't really that eccentric, with the exception of Pluto, so on the scale you're aiming for circles should suffice. One problem with going for the real thing, is that the planets have neither constant linear nor constant angular speed. Instead they cover equal areas in equal time, i.e. the area of the elliptic sector covered by the sun and two points on the orbit is always the same, if the time needed to go between the two points is the same. $\endgroup$ – Duane Dibbley Oct 4 '16 at 0:24
  • $\begingroup$ @DuaneDibbley - if I do opt for full Keplerian precision is it possible to generate the elliptical motion from within Blender, or would that require using the external API? $\endgroup$ – Tom Goodfellow Oct 4 '16 at 2:56
  • $\begingroup$ I've never had to do that, but my guess is that it can be done in Blender, possibly with the help of SciPy, which is quite easy to use inside Blender (see Using 3rd party Python modules). $\endgroup$ – Duane Dibbley Oct 4 '16 at 7:41
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How are you looking to present said orrery, are you planing on taking a few simple screenshots or full realistic renderings?

Will you be presenting some static images, or are you thinking of animations or video? Or perhaps even an interactive/real time game-like demo?

Either way all you want to achieve seems pretty reasonable and relatively withing reach. Blender has good animation and modeling capabilities that suffice for what you want to do.

Since you say you lack the vocabulary and terminology here are some quick keywords and that may be useful for your research and to get you on the right track.

You may need to look into animation and mostly constraints stuff, also Curve path Animations and Follow track. Look for tutorials youtube, there should be plenty to get you started

If you are looking to make some sort of interactive or game-like real time first person demo Blender Game engine may be useful, even though it's considered outdated and stalled in development.

A more flexible and modern approach may be WebGL based solutions like blend4web

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    $\begingroup$ Splendidly helpful! The initial goal is simply animations of coloured blobs moving realistically, probably each animation showing a single point of view. At least I'd want to get that functioning before running away with interactive photo-realism (and of course without a zoom function coloured blobs is photo-realistic astronomy) $\endgroup$ – Tom Goodfellow Oct 3 '16 at 23:47
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    $\begingroup$ Blender is good for astronomical stuff. Source: I use blender to make animation for planetariums. Here's a great resource for textures: svs.gsfc.nasa.gov/3895 $\endgroup$ – Ron Proctor Oct 4 '16 at 0:30

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