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Strange pattern using displacement: cured ;-)

Posted: Fri Apr 09, 2010 2:29 pm
by spekoun
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Hi

Can somebody help me, remove that pattern? I tried many settings, but bo succes. Pattern depend on polygon size of mesh, as you can see on two pictures. Mash is simple flat plane, only sgmented for displacement.

Thanks

Mirek Hons

Re: Strange pattern using displacement

Posted: Fri Apr 09, 2010 4:08 pm
by Bubbaloo
I'm betting it is an issue with mesh subdivision. Can you post a wireframe image? What modeling software?

Re: Strange pattern using displacement

Posted: Fri Apr 09, 2010 4:18 pm
by spekoun
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Here is a wireframe... It is simple. I think I did it correct...

I am using Cinema 4D

Re: Strange pattern using displacement

Posted: Fri Apr 09, 2010 5:31 pm
by Bubbaloo
You're right, it is very evenly subdivided. And it doesn't appear to be a texture tiling issue.

I have experienced this issue too where the following conditions exist:
Relatively large polygons/curved surface
Extra fine detail displacement map
High precision displacement settings

Solution:
Denser mesh. I would subdivide that mesh down a few more times, then those patterns will probably go away.

Re: Strange pattern using displacement

Posted: Sat Apr 10, 2010 9:16 am
by Hervé
Like Brian said... a much denser mesh will cure it.. but I mean MUCH denser.... voila.. 8)

Re: Strange pattern using displacement

Posted: Sat Apr 10, 2010 1:59 pm
by mgroeteke
....or - from a practical point of view - try to use instancing just at the borders area of your mesh. for example along the line which borders to stones, around the tree base etc. this is where single grass leafs will be actually visible in this scene. there are some good tutorials online how to make grass with instancing.

even easier: use a good 'untiled' multilayers grass texture map (overlap real scale textures with different sizes) and paint those grass leafs on borders with an appropriate PS brush. 2 minutes of work but much faster rendering ;)

cheers

markus

Re: Strange pattern using displacement: cured ;-)

Posted: Sat Apr 10, 2010 6:42 pm
by spekoun
Thanks a lot.

I densed mash and pattern is gone. :D

Grass: I am trying to find some workaround very long time. I do not like PS postwork. Modelling grass is too laborious task. Instancing of some "grass tiles" is not universal. So dispalcement seems to be best way for me. But dispalcement takes time to render, it is only one disadvantage for me. But acceptable, because it takes time of CPU, not mine... :wink:

In this render i tried "new" way. I made two planes. Lower one has simple grass texture and upper has displacement with alpha. Upper plane material is besed on the same texture as lower one. And it seems to work fine. I will post final render.

Thanks again for advice...

Mirek Hons