Thank you
All was made with MB3D
But the refraction is very very long to render oO'
Volumetric light : 1h30
Render : 1h
Reflection/refraction : 14h30
It's a "DEcombinate" of two IFS ( Board and Knots) and a General mandelbulb. I just scale and move the object.
-edit- I just launch the MonteCarlo render : remaining : 1 day 21 hours \o/
BASE PARAMETERS (not exactly the parameters for this picture but i you render, the refraction will be rendered, there's no volumetric light here ) :
(the parameters for this picture are lost

)
Mandelbulb3Dv18{
g.....s/...C2...w....2E...E1T7tbbstkzm8bj42Vyv8EBs2DLqMBuynB56eMGyc0.VnNonmRkruD
................................vfa7PZKKl.2........o.hc0...............U4/Y0LDsD
...Uz6....UT..../M.0/...........F.....E3.....UvehS0EA1lD/.Ee58BE...G/dkpXk1.....
zI....cD12..0..........wz.................................U0.....y1...sD...../..
.z1...cD185PJAV5tw1R6cB7xbhwyOv1g68vCbjDnGu7mnnCtvvp6M1hRkJuykOT/s4WWYnDHwgTU.Tb
nvfZz301UUGCzqBPnilafPiDU.....oLw/............oD5s/...sD..G.....................
.............oAnAt1...sD....z.....................................kibALEA....k1.
.....Ksulz1.....zzzz.wV5LU.U..6......s2...EB....Y..........F....6/...I1.....SF52
...U.ydelCeeYFncTeOgOd8No.6..E/.wavW..UJdtvvzczj6YqulQA8Sz1............AlwDwm5B.
.wUmc2beYz1.mIqp.tasz.........../EU0.wzzz1...........s/...................E.2c..
zzzz.............0...................2./8.kzzzD............8....................
/EU0.wzzz1...................................c4Pt/.U.0szz/FMR87..06UzXG6aRKb..6U
.yzdlA6Ub/.U.0sz8DYMQC6..06Uzf2LNWrN..6U.yjyXxaXR0.U.0szXhqavR6..06UzDiQYpNP..6U
.yTMuRdPs/.U.0sz...crIGJzzFoTuIdyzngi8qdxzZX.4rUhZ4PfZrRVZb9e/rN................
E6...AE.W6E.....I....s....UMj3aQYZYFH/EG4B3...........................U1C....6U/
4MU.......UaNaNaNaNizYNaNaNaN6/EnAnAnAnAnz9...............................2.....
........................................................kz1..........cNaNaNaNavD
.....................2.....3....A....gYPjFrQmYYFH/..............................
.sU1....06U.0.U..............S/EaNaNaNaN1.YaNaNaNaV4./..........................
...oz...................6.A........../......../E........kz9........0./..........
OaNaNaNaty1...................../....E/...k0....5JaPZ7LMg/......................
..............U.06U.06U.0...............U.2........6./........zj..........2.....
..............0E................................................................
............................................}
{Titel: Bulbentoure}