Weird Displacement w/ Bitmap issue

[Inhance Digital]

Ive used displacement tons.

I have revisited these fourms for an hour or two searching for my problem, and I dont see it. Its really strange.

Im working on a water displacement map. Ive used that water patch plugin with a gradient height map to derive a displacement map. Map looks great.

The displacement renders with square box grooves all over it. I can go up to 6k map size with a 2D disp. resolution of 6k as well (using 3gb switch) and I get no change. 3D mapping produces the same result. Subdivision result is slightly different, but equally useless.

I have worked bluring, filtering, Vraybmpfilter, various file formats, plane divisions/turbo smoothing, etc. To no avail. I throw another bitmap from my collection (a landscape radar map from the shuttle), and it looks beautiful -- a map thats way more dense and has more detail!

Im at a loss why this apparent clean, simple map is producing this artificing.

Attached is a render of 2D displacement @ 2000 resolution (map as well as modifier), the displacement map, and a subdivision render Edge Length 4, Vdependant, and 256 subdivs.

Any help is appriciated.

[JeffG2]

I have heard about problems with 8 bit displacement maps.

Have you tried a 16 bit version?

[Inhance Digital]

8 or 16 bit

Yes ive ensured it is 16 bit. Various file types.

[vlado]

How did you generate the displacement map? The 3ds Max Gradient Ramp texture only supports 256 levels of colors, so you should avoid it for this. Best to use the ZDepth render element for the purpose, and save to .exr file, just in case.

Best regards,
Vlado

[Inhance Digital]

256 gradient

Vlado,
I generated with the gradient texture. I will do your suggestion now.
-W

[Inhance Digital]

Zpass results

Here are the results. not exactly promising.

The exr vs tga images render much quicker, the tgas have lots of low-power noise all over them that is slightly abated by using Summed Area. I have tried 16 and 32 bit versions of tga, exr and tif. all 2000x2000

The settings are:
2D Mapping
Filter texmap .001
Ammount 14m
Resolution: 2048 (maps are 2000x2000 Zpass scanline element -- also tried VrayZdepth with 16b exr same results)
Precision 60

Maps have standard 1 Blur and Pyramidal filtering. Neither of these two seem to adjust the appearance of the "grid"

The max file to produce the displacement bitmap can be downloaded here: www.triplehelix.com/seasurf.max

thanks again!

[Inhance Digital]

of course..

the max file requires this plugin...
http://charles.hollemeersch.net/Projects/24/oceanwaves
-w

[Inhance Digital]

Fog Pass, Blur

I also have tried using a Fog pass and it produces the same result.
I put the Blur to 2.0 and the offset to .002 to produce this result... 2D mapping 2000rez 20p.
Its good enough, but im still disturbed I couldnt produce a clean displacement from geometry in max, that could come in very handy. Maybe its a shortcoming in max to be able to produce enough shades of grey in a render.