Displacement map "Surface Dithering" problem

Gaurdo · Mar 25 2024

Hi all! I would be very grateful for your help!

Situation:

- I bake Displacement Map 32 bit .EXR through any of the listed Xnormal, Knald, Mighty Bake

- At the output I get a map, when applied, dithering (aliasing, ladders) appears

Image: https://us.v-cdn.net/5021068/uploads/editor/07/zp4s7mthbd0s.jpg

in 3ds max i fixed it with VrayBitmap filtering.

But how to fix it without VrayBitmap, and filter disp. map for zbrush for example ?

Eric Chadwick · Mar 26 2024

This looks like a viewport preview. Bitmaps are downscaled automatically for realtime feedback. What does it look like when rendered?

Gaurdo · Mar 27 2024

Hi there! Thanks for your reply! Unfortunately it has the same condition in maya, zbrush, 3ds max view ports and renders like Vray, Scanline, Arnold. Here is an examples.

Image: https://us.v-cdn.net/5021068/uploads/editor/zc/kw55x52p1qoo.jpg

Image: https://us.v-cdn.net/5021068/uploads/editor/79/56j3sk0dwt6u.jpg

Image: https://us.v-cdn.net/5021068/uploads/editor/gz/h80iay1yvgbc.jpg

But in case of 3ds max, I've found that it changes with different parameters of filtering in a standard max "BitMap" map:

Image: https://us.v-cdn.net/5021068/uploads/editor/j5/qivm9e8dntcu.jpg

Image: https://us.v-cdn.net/5021068/uploads/editor/qg/a4qbrjn03yz9.jpg

Image: https://us.v-cdn.net/5021068/uploads/editor/wy/k7cmf6ec6kzw.jpg

And if i use "Vraybitmap" map, i can manually edit the intensity and chose an algorythms of filtering. And it works great like in a shot below:

Image: https://us.v-cdn.net/5021068/uploads/editor/on/dy0c3epv9zjg.jpg

But the problem is, that it works only in 3dsmax

. And i cant find the way, to filter it in Zbrush. Or maybe there is a way to save a "filtered" version by "VrayBitmap" algorithm out of 3dsmax in a separate file? Or even

Eric Chadwick · Mar 27 2024

Are you sure it’s 32 bits per channel, and not 32 bits per pixel?

Gaurdo · Mar 27 2024

I am not sure, but that what i have when i am open a maps i baked:

Image: https://us.v-cdn.net/5021068/uploads/editor/e7/auns2akgf4rq.jpg

Image: https://us.v-cdn.net/5021068/uploads/editor/13/iyc0qc5zom97.jpg

Some maps i bake with Xnormals, some of them in Knald, some of them In MightyBake. And all of them has the same problem.

Eric Chadwick · Mar 27 2024

Can you share a small example file? Like a 512x crop of the original.

Gaurdo · Mar 27 2024

I tried to crop it in 512x512 but it became too small. Here is a sample of scene i use to make a tests. There is a simple sphere with UVs and a FullFloat 32bit map non Normalized with a simple relief in it. I apologize for sending the file, because you asked to send the croped map. But if I cut the size down to 512 there is no room for any dispalcing information. That dithering effect appears if sphere mesh subdivided 6kk polys and higher. In other words the higher mesh density - more visible "dithering" effect become.

pxgeek · Mar 27 2024

Looks like you're baking out an rgb texture.

How does baking out a 16bit grayscale look?

I've only baked 16bit tif files for displacement and seem to work well enough for me.

Gaurdo · Mar 27 2024

I tried to bake 16 bit full float with Knald, and the result is even more weird.

Image: https://us.v-cdn.net/5021068/uploads/editor/it/d5yzukrnje42.jpg

Image: https://us.v-cdn.net/5021068/uploads/editor/no/mtizx83p4w89.jpg

Tried to bake with Xnormal 16 bit rgb. Unfortunately there is no option to bake it in grayscale, at least i didnt find it.

Image: https://us.v-cdn.net/5021068/uploads/editor/n8/oopm6abiynfm.jpg

Map converted in gray scale in photoshop

Image: https://us.v-cdn.net/5021068/uploads/editor/7b/f7p1z20c3wrc.jpg

Eric Chadwick · Mar 27 2024

Oh maybe because you're using the old Displace modifier? Which renderer are you targeting in Max? If you're using V-Ray, it's better to use the VRayDisplacementMod modifier.

Eric Chadwick · Mar 27 2024

I'm not seeing problems with your ZIP.

Image: https://us.v-cdn.net/5021068/uploads/editor/83/ukktwgrg862z.jpg

This is rendered with V-Ray viewport IPR. I did have to add a Smooth modifier and set it to Smoothing Group 1, just to get nice smooth normals. TurboSmooth is set to 3 iterations.

This is in 3ds Max 2024.2.1, with V-Ray 6.20.02. WIndows 11 Home, NVIDIA GeForce RTX 3080 Ti, 64GB RAM.

What are your hardware specs?

Eric Chadwick · Mar 27 2024

Also what units are you using in Max, and how big is your mesh? I'm using 1 meter, and the OBJ comes in at about 126 meters tall.

Gaurdo · Mar 27 2024

Unfortunately same case with VRayDisplacementMod:

Here is 16 bit TIFF

Image: https://us.v-cdn.net/5021068/uploads/editor/zj/27cgdyy2x55e.jpg

Here is 32 bit EXR

Image: https://us.v-cdn.net/5021068/uploads/editor/cn/jb0dqcen6jom.jpg

I am not targeting to use renderers in max. In that case i just tried to learn how to bake clean displacement maps, to use them as sculpting tool for Zbrush for example. And i made a simple scene with a "Reference Deformed Sphere" with one pressed outside and one pressed inside relief. And the task was to recreate defromations from "Reference Sphere" on a "Target Sphere" by using just a displacement technology. And i thought it would be easy =(

Image: https://us.v-cdn.net/5021068/uploads/editor/8t/jk4g32zrwbsv.jpg

Gaurdo · Mar 27 2024

So in that case. Even if i use VrayBitmap Filtering to fix that problem in 3ds max, i cant fix it in Zbrush. That is why i am trying to understand why that "dithering" effect appears.

And also i am very grateful to you guys for your support.

Eric Chadwick · Mar 27 2024

Hardware specs?

Gaurdo · Mar 27 2024

Intel Core i7 3770, GTX 1070, 32GB RAM.

Gaurdo · Mar 27 2024

Oh i am sorry i didnt recognize your reply here 12:33AM, really sorry for it. Big thanks to you for your tests. May i ask you to increase Turbosmooth iterations up to 7 or 8 to get sphere 8kk or 24kk? Because it works fine even for me on a low subdivs.

Image: https://us.v-cdn.net/5021068/uploads/editor/qy/zx54bl07ht9j.jpg

Image: https://us.v-cdn.net/5021068/uploads/editor/xa/td34z7sc2wt2.jpg

Gaurdo · Mar 27 2024

I use centimeters as units.

Eric Chadwick · Mar 29 2024

Turbosmooth set to 7 is insane overkill, but ok.

I imported the OBJ and reset Smoothing Groups to a single group. I added a Slice modifier to cut away the rest of the model. TurboSmooth at 7. Displace, and loaded your EXR in the OSL Uber Bitmap node. Maybe your import settings need adjustment?

Image: https://us.v-cdn.net/5021068/uploads/editor/qm/cdvx6dlcz1jj.jpg

Eric Chadwick · Mar 29 2024

FWIW, here's my MAX file. Just add your "disp map.exr" and turn on the TurboSmooth (off to decrease file size).

Gaurdo · Mar 30 2024

Hello again! I tried to open the file. But my max is to old to make it.

Now i am trying to replicate the scene by your description, with OSL Uber Bitmap Node.

Eric Chadwick · Mar 30 2024

Which version of Max are you using? I might be able to down-save to it.

Gaurdo · Mar 30 2024

2022

Eric Chadwick · Mar 30 2024

2022 version!

Gaurdo · Apr 1 2024

Huge Huge sorry !!! Newbie is in action. I gave you a wrong file.

I recorded the clip to explain the situation. Please watch in 1.5x, my English is very bad

https://www.youtube.com/watch?v=FTQO8PvuDtQ

Hope you still interested.

And also here is a correct file, but i think its already useless.

Displacement map "Surface Dithering" problem

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