Color Start / End difficult to control in v1.7, even harder in v1.8

[brandpeter]

In version 1.7, it was difficult, but possible, to set the position of the Start and End colors using the sliders and the fine button such that you could isolate a color to a particular area of the object. For example in the image http://taiji-tu.deviantart.com/art/Drilling-for-Sulfur-on-Io-350248191, I was able to isolate the red specular color to just the "drill bits" part of the image. To do that requires accurate setting of the color sliders so that you can control how the color pallet is spread over the object. Sometimes the dark vertical bar in the pale yellow strip between the sliders (don't know what you call that - visible object value range?) is very thin, so that makes it even harder to set the sliders.  In version 1.8, that process is now impossible as the sliders seem even more sensitive, and the vertical bar even thinner. If you touch them, the colors are all over the place, or you end up with just a small part of the pallet being applied to the visible object.

It might of course be that I misunderstand the role and function of the controls. My suggestion is to expand the vertical bar when the fine button is selected  such that it fills as much space as there is on the horizontal, and to allow more sensitivity-control over the sliders with the arrow and ctrl/shift/alt keys. Alternatively, have a button that sets the start and end markers to map the entire color pallet over the entire visible part of the object(s).

Thanks.

[Jesse]

The basic concept of the fine adjustment is when pressing the button the current start-end position is spread to _nearly_ the whole range. Nearly only, because the maximal range is 15 bit internal, but to allow the sliders to be more far away from zero and max, it is extended.
Make the coarse adjustment sliders as close as possible to widen the range the most when pressing 'fine'.

In your case the OTrap option gives not much differences and with the 15 bit internal limitation (every bit from the 18 Bytes per pixel is in use), it is a little tricky part to adjust it fine.

For the default option on smooth-iterations (Color on 2nd choice not checked), the maximum range is from 0 to max iterations.
Because of that you should not set the maximum iteration value to high, 200 is for most cases enough.

But there is a little issue in certain situations that i will fix somehow, there is a term to subtract+add a value to the smooth iterations to make the coloring more stable on zoomings, but this can lead to negative values that are clipped!
So it might be if there is only a little thin yellow line visible on the 2nd or 4th marker, that there are no color informations at all.

But in your case with OTrap coloring, there are no changes between the last versions, you should adjust coarse mor rigid, for example with arrow keys, and then you press 'fine'.

Hth, cheers

[brandpeter]

Okay I'm beginning to understand the maths a little better, thanks for your reply. Here's a better example that illustrates the difference between 1.7 and 1.8 though. In the 1.7 version below the boxIFS renders in blue to simulate water flooding the chamber. Rendering those parameters, with no changes, in 1.8 makes the entire image blue. Changing the coloring mode in 1.8 doesn't give me a workable range except for "Color map on input vector", but that gives me concentric bands of color emanating from the center of the image criss-crossing the boxIFS.  I also tried the new transparency setting (cool idea!) but didn't see any difference in the image. I was expecting to see something through the blue color; am I missing something?

In 1.7:
Mandelbulb3Dv17{
Y.....Y/...u1...w....2A...USdP9G4Ysozyd1yGxeDI4EhQdky9/h7znWPl9KTkGzyStoyjZUC5xj
................................U/5/XmJSV/2........Y./..................N/2..U2F
...Uz.....kI..../oU//...........y/...2E3.....U6MxpOQ1EiD/oEyxqrD...G2dkpXm1....U
z..kviPD12..02UNaNaNaNaxz...........I.....Uadl9...........0u1....y1...sD...../..
.z1...sDkNU./67ruo1OLywelB.tySe.HN/6Z/VDCDVlPEic.vP3/QKScZ.2yYal0eoZHCiDiXm7ARtY
Xvf4o2r8BIouxKgSUd/tW0gj......2K2...TI........sD.6....sD.6E..Udqe2UCXDwDP6iwSUIW
AwX0G9N/7xXozqAnAt1...sD....zU/Se9.isdi.MZbu0UTSe9.audi.sgbu0UxSe9UeUN/EE....2..
.....MEUZz1.......kz.wzzz1.U..6.P....61...EB....m....c3....F....8/...Y2.....S/5g
...U.qyvlzzFdMlzlXr7zzilZ/6./c..zzzp..kuvBTuCfxj/6gJ7KDgdz1..........kE6/lzzk9B.
..9wbvo87z1.WeQKtQg7z.Uxa9yQR7xj/6U0.wzzz1................................E.0c..
zzzz.................................2U.8.kzzzD.................................
/6U0.wzzz1...................................wPjp0k39M0.xIE9otB.P209.Ux4zFVI.w19
q.UnW6hUH.......QUIbK70......wcNG9s2......UAl7yLN1U79E0.Khr.8M/.NLxz.stT/UlD.Uit
z1EezBfSt1k39M0...kguZD.OHE9otB./llTI63..B2yKD7.................................
E6...A....E.....I....o....UMjVLG4B3.4B3..................................sU1....
/6U./2.....zd4joB74UzE8QxckpXWxDTIsuFVf5Zz1..........xbOwGrYM.yD7AFexsxdNy9aOfG.
uAykz0.............................wz...................kz1........wz...........
.....................I.....3....7....22JZFbQVNpI..kRZ75.........................
.Q...MU/46U..........6.........koAnAnAnAXz1AnAnAnAnuz...........................
..UD./.......O3E...................wz...........................................
................................/....E/...E0....fxqMcxpMp7KN.kKRn/..............
..................U/4M..................kz1........wz.........zD/.......G.wzzzzz
zzzzzKzzzzzzzzxj.............................O2E...................sz..........E
............................................}

And best I could get in 1.8
Mandelbulb3Dv18{
e.....m....x/.../....2A...USdP9G4Ysozyd1yGxeDI4EhQdky9/h7znWPl9KTkGzyStoyjZUC5xj
................................U/5/XmJSV/2........Y./.........E........N/2...wD
...Uz6/...U4..../kU//...........y/...2E3.....U6MxpOQ1EjD/.EyxqrD...m1dkpXm1.....
z..kviPD12../2UNaNaNaNaxz...........I.....Uadl9...........W0.....y1...sD...../..
.z1...sDkNU./67ruo1OLywelB.tySe.HN/6Z/VDCDVlPEic.vP3/QKScZ.2yYal0eoZHCiDiXm7ARtY
Xvf4o2r8BIouxKgSUd/tW0gj......I//.............sD.6....sD36E..Udqe2UCXDwDP6iwSUIW
AwX0G9N/7xXozqAnAt1...sD....zw1...................................UeUN/EE....k1.
.....a0Ljz1.......kz.wzzz1.U..6.P....61...EB....m....c3....6....a....Y2.....S25g
N63U.qyvlzzFdMlzlXr7zzilZ/6./c..zzzp..kuvBTuCfxj66gJ7KDgdz1..........kE6/lzzk9B.
..9wbvo87z1.WeQKtQg7z.Uxa9yQR7xj/6U0.wzzz1...........s/...................E.0c..
zzzz.............0........E..........2U.8.kzzzD............8....................
/6U0.wzzz1...................................wPjp0k39MW72skTI63.zkWBzgl5G9s2....
...Kn2Yhk.......6NIbK70......EoJWzJq.Mm0YM0gZp0RS1k4Vkmz0jr.8M/.NLxzzruT/UlD.Uit
zzzgzBfSt1k39MW7..kguZTaOHE9othO/llTI6pC.B2yKDNq................................
E6...A..F7U0....I....o....UMjVLG4B3.4B3..................................sU1....
/6U./2.....zd4joB74UzE8QxckpXWxDTIsuFVf5Zz1..........xbOwGrYM.yD7AFexsxdNy9aOfG.
uAykz0.............................wz...................kz1........wz...........
.....................I.....3....7....22JZFbQVNpI..kRZ75.........................
.Q...MU/46U..........6.........koAnAnAnAXz1AnAnAnAnuz...........................
..UD./.......O3E...................wz...........................................
................................/....E/...E0....fxqMcxpMp7KN.kKRn/..............
..................U/4M..................kz1........wz.........zD/.......G.wzzzzz
zzzzzKzzzzzzzzxj.............................O2E...................sz..........E
............................................}
{Titel: Temple of the Sun God}

Titel - is that the Title?

Oh yes, as a side issue, I notice the settings panel gets truncated - might have something to do with the Win7 skin I use. In the Coloring tab, the last setting "Dyn Fog on Iter." in only partially visible. I'd send you a snapshot but not sure how to attach an image in this forum. Do you need that?

I am not skilled in the mathematics you use in calculating the fractals so bear with me please. As far as I can tell, you calculate a color-value of each pixel on the object based on iteration-depth and coloring-mode etc., then map the color-values to an output-color using the pallet and its settings. If we zoom in, then we are restricting our view to a narrow band of the color-value range which shows up as a thinner vertical line on the slider range yellow bar thingy. Am I close?

[Jesse]

Thanks for the infos,
to the first parameters i can say that it works for me on version 1.8.2 and the latest i am currently working on, so i guess you won't have to change there much for the coloring.
You could see through a transparent slice if calculation depth is 2 or higher, but in case it would be all solid underneath the surface, no difference between the objects are made yet, so there wold be no structure visible inside the box.
Maybe i do this option when i got the time for, i would also send you a version with this slice and transparency but maybe the current beta got some coloring trouble and this would not be displayed like it should.

Your assumptions on coloring are ok, but zooming in does not necessarily lead to a more narrow coloring band.
It will move to the left side because more iterations are needed (higher values are on the left side for smooth-its), the width depends on the variation of the smoothits on the surface, and the surface is usually given by the DEstop value, meaning at a certain distance to the real fractals solid surface, what is only an estimation of course.

If maximum iterations is reached the smooth iterations stay at this count of course, then you shold increase maximum iterations.  You see in Infos the maximum calculated iterations for evaluuating this.

[brandpeter]

Thanks for the reply. The version I tried is your latest beta - 1.8.7, sorry, should have been more explicit.

I will try playing around with the iterations and DE stops to see if that gives me a wider band, and I'll shrink that boxIFS to a height of almost zero to make it a plane. Thanks for the tips.