Thank you for your comments, and thanks Syntopia for that renders, looks nice!
For you, Luca: I've managed to do this in M3D, using the transforms _absx, _absy, _absz, _sphereinv and addC
Julia values are : x=-0.3 y=-1 z=-1
The second one has a cut at z=0, y=0
Iterations and bailout values had to be tweaked.
I'll do more with better resolution later...
And I'll ask Jesse if he can make an optimized formula for this!
This are the parameters for M3D:
Mandelbulb3Dv16{
N.....Y/...E4...I....26..............1.......s1E................................
........................................I.2........../..................y.2.....
................/M.0/....6k3/...00....E2.....M8bjMjLw3nD/..........c./...wX/OaNa
z.UaNadD....02kAnAnAnAnoz0........zj........kz9..................y1...sD...../..
.w1...sDYsAIxzzzjznam5zggaB2zstjuFZpIEljTcFzUvMS3t9VsNWPqD6uzkplDbe3FGyDMaO9c9iB
OwXT/M/eK27tzqx3Mkax1WyD......YVC.....................sD.2kz0...................
..............................LRR6.0qpV.UOL50UnRR6.orpV.cVL50.ESR6..............
................0....wzzz1UL.22.H1...g1...kD....r1...w2....F....8/...cXz..UWGV2Q
...U.yzzzzzzzzzz./6Uz16U.0M..c../DtQ.6UkKZMxkayDPt41pmERLz1............68.kzzzD.
z.BC4POwozvV2RiGMQZtz0..........36W0zzzzz1UjJZPmF4WQzEislFs.YNxj3wLYcXY8NzH.0c..
zzzz.................................2U.8.kzzzD.................................
/6U0.wzzz1....................................aBT..Do21.rslP6R1.P/YB.YFGa728.gnB
q.Esn3bBT.EEUA/.8xLM7t1.mlKO.UqTVl36.Uk/3..WzNqET.EX0a5.WyrGqI2.6Mk/.QwTpxH6.EaD
e.UvzRoBD/UYAG7....y3q/.zz/k.1A.yz1yAT2.xzpaqa9.................................
E....M..........zzzzz1......iFLNbJaQU.pPrJaQ.........................c..........
...................0./........zj................................................
................................................................................
.....................2.....3..../....wJEWB5K.656ExqRZ75.........................
........................................kz9.....................................
................................................................................
................................/....E/...E.....T3YMnZ3.........................
................................................................................
................................................................................
..........................................E.....I....2....kL/7qQO/..............
................................................................................
................................................................................
.....................................................2.....3....2....wpQkVKNmJKO
iN5.Vl4.........................................................................
..............zD................................................................
................................................................/....E/...k.....
T34NYB2.iR4QgJrQ.c3.....................................................kz1.....
...wz.........zD........kz1........wz.........................................zD
.........................................................................../}