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Displacement problems....

Posted: Sun Jun 28, 2015 7:27 pm
by GordonOfPallion
Can anyone tell me why I'm getting this aliasing problem around the edge of the tick?
01.jpg
The level of detail here is 8k, it's driving me crazy as I've got a mega tight deadline.

This is what I'm shooting for...

https://vimeo.com/95959829

Any help smoothing the mesh would be greatly appreciated...

Cheers,
Gordon

Re: Displacement problems....

Posted: Sun Jun 28, 2015 7:45 pm
by aoktar
Is your image big enough as 2,4 or 8k?

Re: Displacement problems....

Posted: Sun Jun 28, 2015 8:22 pm
by GordonOfPallion
Thanks for the quick response Aoktar.

The image that's driving the displacement is 2K but I've tried it at it's original size of 7k and it's the same result.

Re: Displacement problems....

Posted: Sun Jun 28, 2015 8:24 pm
by Yambo
actually i had the same issue. even with high quality maps.

Re: Displacement problems....

Posted: Sun Jun 28, 2015 8:35 pm
by aoktar
As you notified the messages in forum, %30 is around the displacement. But i have not any control over this feature. It's a Renderer behaviour. It's working without pre-tesellation of triangles else other renderers. It generates some virtual polygons on rendertime. It's fast because of this but slow when you increase much. Also have some problems.
So i just can try to give some advices. And i have spent much time due this kind of limitations. You may try to generate a anti-aliased 32bit images and map it. It's working much better with float(32bit) images.

Re: Displacement problems....

Posted: Mon Jun 29, 2015 6:13 am
by bepeg4d
hi,
32bit helps a lot and you could add also a little bit of blur in PS to help the displacement in the borders ;)
ciao beppe

Re: Displacement problems....

Posted: Mon Jun 29, 2015 8:19 am
by atome451
Hi all,

More than the blur, you need to feed the Octane displacement with a subdivided base mesh. By sample a plane with 150 x 150 polygons. Of course, it will take more memory... :roll:
Here a screen capture with a 4k 32 bits map without blur and a bezier curve.
displacement_curve.jpg

Re: Displacement problems....

Posted: Mon Jun 29, 2015 9:07 am
by GordonOfPallion
Yep, that's it!!!!

Can't believe I didn't think of that as a solution.

I don't think that was covered in the tutorial but it feels like the most important part of the process to me.

Thanks a lot for your help atome451!!

Re: Displacement problems....

Posted: Mon Jun 29, 2015 9:23 am
by bepeg4d
The quality of the map itself has the biggest impact, here is an example of one poly plane with a 4k 8bit map and 1 pixel gaussian blur:
Schermata 2015-06-29 alle 11.07.17.jpg
In theory, the displacement should give high details to low poly meshes, the need to subdivide the mesh should not be necessary, in my opinion :roll:
ciao beppe

Re: Displacement problems....

Posted: Mon Jun 29, 2015 11:04 am
by atome451
bepeg4d wrote:In theory, the displacement should give high details to low poly meshes, the need to subdivide the mesh should not be necessary, in my opinion :roll:
You are right. That shouldn't be necessary... But if you turn your sun and reduce its size to see the curve of your displacement in a sharp drop shadow like in my sample, you'll see cracks in the curved shadow like the sample from GordonOfPallion. ;)