Fine lines in 3d displacement

[Neilg]

I've been trying to get rid of these for a couple of days now, but I cant figure out whats causing them.
Here's a crop of the full res at 6k wide:


It's 3d displacement (modifier), using a procedural noise map. I've changed the subdivisions from 8 to 32 (any higher and it wont render) but the size of the lines dont change, so i'm not sure if it's that anymore. Edge length has been anywhere from 4-12, same result. I've put a meshsmooth of 2 on the base mesh and converted it to edit poly (it's incredibly dense now - i thought it was getting to be a bit too heavy before...) and it's not changed anything.
I've tried with filtering (in the dispmodifier) off, on, and with values of .001, .01, .1, and 1. 1 was unbelievably slow, and pixel perfect to the .001 version.
Blur in the procedural noise maps is just set to 1.

Any ideas?

[Karrde]

Perhaps you have Real World UVW coord on the mesh? They tend to be automatic in the 3ds max Design, and some procedurals, noise included do not like them and end up reandering small squares. I'm just not sure whether under those lines is a already displaced surface (which render my theory void) or just the model.

[Neilg]

The surface is displaced - it looks fine zoomed out. It's just when you render it really high res, those lines start to become visible.
it's all object xyz. It's procedural so you cant select real world scale, the scale is set in the size part of the noise parameters.

[Codi]

What kind of noise are you using? If I remember correctly, 3DSMax noise hasn't much accuracy and might show some stepping if it's used for large displacements.

[Neilg]

er. yeah, thats the one. the 3dsmax noise.

any fixes, or am I going to have to redo it with bercon noise or something?

[Codi]

I think I got this from this thread:
http://www.chaosgroup.com/forums/vbu...ement-Glitches

I don't really know if Bercon is any better, you could try it. If the problem really comes from a lack of accuracy, you only need to fix it for the biggest displacements, for the small ones regular noise shouldn't be a problem.

Maybe it's how you have set it up already, but I'd use geometry to rough the biggest waves and displacement for the rest.

[Neilg]

he mentioned about scaling down the uv and scaling up the procedural scale... gonna give that a go

[Deflaminis]

I wonder if the "Keep Continuity" tick box would help.

[airstyle]

Here's something to try, a really useful trick I figured out by accident: Render your procedural materials to texture ('0' on your keyboard) and make sure use existing channel is selected. What you will end up with is a usable UV Texture of any size of your procedural map! That might get rid of your lines as it isn't computed at render time.

[Neilg]

Here's something to try, a really useful trick I figured out by accident: Render your procedural materials to texture ('0' on your keyboard) and make sure use existing channel is selected. What you will end up with is a usable UV Texture of any size of your procedural map! That might get rid of your lines as it isn't computed at render time.

To end up with the detail i'd need but at the scale this is set up at... I dont even want to think of how big i'd need to render it. no less than 20k wide, if not more.

[airstyle]

It's a quick render as you're only rendering the texture - 20k might be pushing it as I've had problems with vray and 15k+ renders before - the thing is you don't need to use vray to render out the texture so scanline should be able to handle that.

[Neilg]

Wouldnt my memory usage go through the roof? I always thought using maps that big in displacement was a major no.

Got some other stuff to get out today and should have free time tomorrow to do a series of tests of everything in here. They cropped out the worst patch of lines so I think we got away with it on those

[GLASS-CANVAS]

The last time I saw this problem it was caused by having the Noise map's Source set to 'World XYZ' rather than 'Object XYZ'

[LarsSonparsson]

Had this same problem year ago. The problem really is in Max noise texture in 64bit version.
You could try Bercon maps.

Here is link to old thread back then.
http://www.chaosgroup.com/forums/vbu...-t-seen-before

[Neilg]

oh no. I even posted in your thread

I need to start paying more attention.