Impossible Worlds

Although I was pretty happy with the DEM terrain mapping described in my last post, I was aware that it didn't exactly show off the incredible flexibility that moving to voxels provides over the more traditional height-field grid techniques I employed in some of my previous projects.  You pay a massive cost in complexity, computational cost and rendering performance moving to voxels so it seemed a bit poor to not show off their strengths a bit more.

To this end, and just to have a bit of fun, I've been playing about with the underlying distance field functions my planets are based upon.  All the images in the previous post used a simple spherical distance function to give a basically realistic planet shape, but there's absolutely no reason (discounting physics) not to use any arbitrary function to produce the underlying shape upon which the DEM mapping works.

Here are a few of the toy-worlds I came up with:

Why not have a cube world...
  (maybe the birthplace of the Borg?)

Or a torus?

A union of three cylinders with a bit of -ve blending at the intersection

...and my timely tribute to Halo 4...

Obviously the terrain system copes with varying degrees of success when applied to these unconventional shapes but considering that it was designed for spheres it's surprisingly decent.  A proper parametric mapping would work better for the shapes that have one but these experiments are just toys after all.

Blobby world based on a low frequency noise function

Although the plan is for planets in my universe to be in general constrained by the laws of physics and nothing like these, this generality of form opens the door for having blasted husks of planets with huge chunks missing, cracked open meteorite ravaged planetoids and maybe just the odd eccentric alien world...