Hello everybody...
I'm currently working on a procedural dunes generation, and I'm not far to get what I wanted,
using the functions.
But I've got a big problem with the renders : multiple thin lines appears everywhere and I
don't know how to avoid them. See the renders below.
When the camera position is near the ground, it seems to be worse.
Have you an idea to solve this problem ?
not sure, but is this caused by some smallest scale displacements being too small?
very likely, if you ask me. Try a bigger smallest scale (1 cm for testing) and see if they go away.
I deleted the displacement and the functions that made the small sandwaves.
The main displacement (that makes the dunes) as a value = 7.
There's no improvement... I would even say it's worse !
See the attached files.
do your functions potentially produce divide by 0, or coming close to dividing by zero?
Not much divisions in my functions. When I use a "divide scalar" it is with a constant value.
There's no "division by 0".
I sent my .tgd file in the previous post, if you want to make a test by yourself.
WTF?
I added a "compute terrain" node (default), between the last multiply scalar and the surface layer, seems to be working ... :) I'm on a slow laptop so it'll be an hour or so till the whole frame is complete.
:)
Richard
ps damn that's some fine functions you got there ;D
pps: I'm rendering your "quick render" settings
I just tried your compute terrain (I've got a quad-core, it's fast). Does not work, unfortunatly...
Interesting, I've only got 1 error so far similar to yours and I'm halfway through the render.
Attached file in case I didn't explain something right.
:)
Rrichard
ps when I first did this I copied and pasted the "compute terrain" from your set up and used that between between the last multiply scalar and the surface layer. Unfortunately I forgot to tick "enable" lol
I've still got the thin lines with your file !
Could you make another test : a render with my first file, without modification ?
Sure :)
Rendering again with your original unmodified file.
I just uploaded the modified render, there is one line, but that's all.
I've wondered for a while if different processors might produce slightly different results at extremes.
Richard
I think it's a multi-threading bug. With max threads at 4 threads I got the spikes, with max threads at 0 I got no spikes. It's probably one of the function nodes or shaders, but I haven't figured out which one yet. If you discover which node is causing the problem, please let me know.
For the sake of completeness here's the render done with two threads at its original settings. Still one error.
Richard
I was just rendering the same view with min/max threads = 1 and there's no spike !
I'm going to reduce the whole process, function after function, until the spikes disappear. Then I tell you.
I'm nearly sure that it has something to do with the "Perlin 3D scalar".
When I delete all of these P3D from my process, I have no more spike (see the new render).
Now I'm rendering another view where the landscape is based *only* on the Perlin 3D scalar, and the spikes come back.
So, what can I do now ? :-\
Looks very good. This is a technique I have been wanting to explore, but do not have time for yet.
Test your inputs and settings to the Perlin 3D Scalar and see if it's being caused by extreme settings/inputs.
- Oshyan
Thanks for narrowing it down. I don't think there's anything unusual with your setup. No further testing needed on your part. It's probably something I overlooked when making the Perlin node safe for multi-threading, or I incorrectly optimised something later. I'll fix it.
Just to add, I've been experiencing the same problem when using Perlin too.
I still got the problem with the new version (2.2)... :-[
This issue has not yet been addressed. Please refer to the release notes/change log for each release as all changes, fixes, and new features will be detailed there:
http://www.planetside.co.uk/content/view/59/97/
- Oshyan
This topic was opened during last january and (considering the last answer from Matt) I thought where would be a fix for this problem... now I can see it was totally forgotten.
Yip, i get the same error. something is wrong with the perlin noise node. but well, you can use a power fractal instead.
Quote from: wiwine on December 05, 2010, 05:07:46 PM
This topic was opened during last january and (considering the last answer from Matt) I thought where would be a fix for this problem... now I can see it was totally forgotten.
I'm sorry about that. I'll make sure it's in the next update. We'll also have a much faster turnaround on the next update.
Quote from: wiwine on December 05, 2010, 05:07:46 PM
This topic was opened during last january and (considering the last answer from Matt) I thought where would be a fix for this problem... now I can see it was totally forgotten.
I think that's reasonable.
No more problem with the new version. Thank you very much ! :)
Now I can go on with the "dunes & sandwaves construction".