Title: Glitched Gnarly Post by: mario837 on July 04, 2011, 08:39:27 PM Glitched Gnarly
(http://nocache-nocookies.digitalgott.com/gallery/7/3241_04_07_11_8_39_26.jpeg) http://www.fractalforums.com/index.php?action=gallery;sa=view;id=7769 Credits to Xantipa2 from dA http://xantipa2.deviantart.com/art/MB11-Gnarly-3-216392072 If anyone volunteers to suggest how to correct the glitches I will be very grateful. My params: Mandelbulb3Dv17{ P.....K0...M7...61...2A....EvC/5c8v3.zWn5CipTH/khI09ZcDQG.g7Aa5KaOdtzEiWrEA07S/k ................................yJp/JtKqP/2........Y./..................y.2..... .................ME38....6UFH...J0....E4.....M1XswUFy0iD/..........c./...w1....w //U0LD0D/.../2.........2.1........zD........I.A........4./E......y1...sD...../.. .wHnAnQDj5fLtH1Yvvn0opYuteKnyA2Zw.pCc8jj242nhB7JlvH5XhbcA4awyWn4k.C.vLjD30k9LeoH TvvIMHxg7yvyye2GJE0N62jj......2jy.............kD.2....sD.6kz.................... .............................UTRWE.Yq70/cQb62.wRWE.Ks70/kXb62UMSWE.............. ................ezzzzzzzz1.U..6.f....66...k8....53...E3...U8....A.....Xt...1GHx8 ...U.0aZczDM6/nz....zX6dE166lc..zrhe.w1osMgdlHzjRy8pJs/mpz1...........W.8.UQgk0. aFBqwnQahzn6mIqp.ta..1..........U6U0.659g.U9M4n5/A7mz0CwQOr9PExj...........60c.. F3JI.EgI7TMmL4.EU1Dbqxm4Iz9...........WA8..k.1A.8LsffaWeYzv8CXieHq7../.......... /6U0.wzzz1...................................UTVR.kzz16.aB/k.1A..1Ak.In4.1Ak..Ak .1kdX.2U.0.y3q/.rumsha..snwF.gaCPOPi.gdht0UXAVTVR..y3q/.H1qaqa9.POPi.AOPDxoH.Qxp L1kzz/6U./.k.1A....y3q/.zz/k.1A.yz1yAT2.xzpaqa9................................. E....E...../....2....A....EEh3aSdtqNU6oPs/.IjR5.......................k/9....... ..........kkpX0LD8QzzUf53iSIsuvDg53iSIsulz1..................................... ................................................................................ .....................c.....3....3....wpNi3aQg71F.A4R..pPr/...................... .....................g53iSIsu/zDOaNaNaNatyXaNaNaNaNiz........E/E..........2..... ................................................................................ ................................8....E/...E.....TB3QcJaQZNoPgFKOiRKA............ ...........0............................Ez1..................................... ................................................................................ ..........................................E/....I....Y....kOjB4OTBKRWJ4....IjR5. .............................MU/4..................wz.........zD........kz1..... ..............................................................................yD ........Uz9.............................................} Title: Re: Glitched Gnarly Post by: cytotox on July 06, 2011, 01:04:22 PM OK, I volunteer ... :D
(By the way, this is a nice parameter / formula combo) For a quick check, I first reduced the size of the render by a factor of 4 (to 600 x 600) while decreasing the DE stop by the same factor (to 7.5). After rendering, I adjusted some of the parameters in the 'Calculation' tab, enabled the 'Recalculate a selection' function in the 'Post processing' window, drew a rectangle around one of the more obvious noise artefacts, and re-rendered the selection by pressing the 'calculate' button (in the 'Recalculate a selection' part, the one beside the 'Enable' checkbox). Basically, I activated 'normals on DE' and adjusted the 'Stepwidth limiter' to 0.03, but the most helpful thing seems to be to reduce the value of the 'Raystep multiplier' to 0.001, which seems to eliminate most of the artefacts (a slight noise on the edges of the ribbon structures can still be seen), but unfortunately also increases the render time to ~16 hours on my machine (for the render with the original size of 2400 x 2400 with DE stop reset to 30) ... As you can see, one artefact in the center of the gnarl structure persists, however. Decreasing the values of the Raystep multiplier and Stepwidth limiter by several orders of magnitude did not help in this matter. However (and strange enough), you can get rid of the artefact by setting the 'Raystep divisor' in the 'Recalculate a Selection' section to 10 (with Stepwidth limiter and Raystep multiplier at 0.03 and 0.001, respectively), and then do the recalculation of the selection, which should take about 10 to 15 min. Finally, before exporting the image, you have to recalculate the ambient shadows once again (this will be done for the whole render, but takes only some additional minutes); the recalculated section will blend in with the rest of the image. In effect, you can use this procedure as a kind of cosmetic surgery to selectively remove some artefacts from any image without having to re-render the whole thing using extremely slow calculation parameters. :dink: I do not really understand why increasing the 'Raystep divisor' by a factor of 10 does the trick, while reducing the 'Raystep multiplier' by the same factor does not achieve this: according to the tooltip, the Raystep multiplier is divided by the Raystep divisor. :hmh: :hmh: If you are interested, I may send you the final 2400 x 2400 image via private mail (I don't know if it is possible within this forum to somehow exchange email addresses ...) Title: Re: Glitched Gnarly Post by: mario837 on July 06, 2011, 07:13:01 PM cytotox said
Quote OK, I volunteer ... First of all I would like to thank you very much for the masterful lesson you have given me! I never used the post-processing "Recalculate a selection" because of the color distortions I observed. I think it is now clear what has to be done. I got stocked with the RSM and SWL, having made renders with values close to yours: 0.01 and 0.001 respectively. Your explanation is a tutorial in how to improve a sloppy render. The question you pose on the different behavior of "Raystep divisor" versus "Raystep multiplier" is probably one that Jesse some day will have time to investigate. Finally on the 2400x2400 image I think my e-mail is published in my profile. Just in case, it is mario.olive@gmail.com. However, I have taken the compromise with my fractal conscience: I will follow step by step your recommendations and get it for myself. This way your time will not be wasted! I will re-post the resulting image with due credit to your contribution. Thanks again and be well, Mario Title: Re: Glitched Gnarly Post by: Madman on July 06, 2011, 07:45:46 PM Thanks Cytotox! I'll keep the Ray step divisor trick in mind. I do like to work with combo's with "difficult" DE's now and then, so I'll have a try next time.
Title: Re: Glitched Gnarly Post by: DarkBeam on July 07, 2011, 07:17:24 AM Some "attractor" formulas tend to distort a lot the vector space, when you use normal density some zones become so thin that the derivates fail. I think! :D Cheers ... Luca
Title: Re: Glitched Gnarly Post by: mario837 on July 07, 2011, 06:52:50 PM After doing the homework indicated by cytotox, I uploaded the resulting 2400x2400 version in dA http://mario837.deviantart.com/art/Glitched-Gnarly-Fixed-217136542 The only addition I made is increasing the 'Stepcount for binary search' to the maximum value of 31. As you can see, a big difference! The params, before the 'Recalculate Selection' step, are below: Mandelbulb3Dv17{ P.....K0...M7...61...2A....EvC/5c8v3.zWn5CipTH/khI09ZcDQG.g7Aa5KaOdtzEiWrEA07S/k ................................yJp/JtKqP/2........Y./..................y.2..... ................/Mk58....6Uxb...J0....E4.....M1XswUFy0iD/..........c./...w1....w //kPGAcC/.../2.........2.1........zD........I.A........4./E......y1...sD...../.. .wnX0LDDj5fLtH1Yvvn0opYuteKnyA2Zw.pCc8jj242nhB7JlvH5XhbcA4awyWn4k.C.vLjD30k9LeoH TvvIMHxg7yvyye2GJE0N62jj......ojP7............kD.2....sD.6kz.................... .............................UTRZE.YqJ0/cQL72.wRZE.KsJ0/kXL72UMSZE.............. ................ezzzzzzzz1.U..6.f....66...k8....53...E3...U8....A.....Xt...1GHx8 ...U.0aZczDM6/nz....zX6dE166lc..zrhe.w1osMgdlHzjRy8pJs/mpz1...........W.8.UQgk0. aFBqwnQahzn6mIqp.ta..1..........U6U0.659g.U9M4n5/A7mz0CwQOr9PExj...........60c.. F3JI.EgI7TMmL4.EU1Dbqxm4Iz9...........WA8..k.1A.8LsffaWeYzv8CXieHq7../.......... /6U0.wzzz1...................................UTVR.kzz16.aB/k.1A..1Ak.In4.1Ak..Ak .1kdX.2U.0.y3q/.rumsha..snwF.gaCPOPi.gdht0UXAVTVR..y3q/.H1qaqa9.POPi.AOPDxoH.Qxp L1kzz/6U./.k.1A....y3q/.zz/k.1A.yz1yAT2.xzpaqa9................................. E....E...../....2....A....EEh3aSdtqNU6oPs/.IjR5.......................k/9....... ..........kkpX0LD8QzzUf53iSIsuvDg53iSIsulz1..................................... ................................................................................ .....................c.....3....3....wpNi3aQg71F.A4R..pPr/...................... .....................g53iSIsu/zDOaNaNaNatyXaNaNaNaNiz........E/E..........2..... ................................................................................ ................................8....E/...E.....TB3QcJaQZNoPgFKOiRKA............ ...........0............................Ez1..................................... ................................................................................ ..........................................E/....I....Y....kOjB4OTBKRWJ4....IjR5. .............................MU/4..................wz.........zD........kz1..... ..............................................................................yD ........Uz9.............................................} |