How to Eliminate or Reduce Triangles?

Inkubo

I'm trying to make a model of a cliff wall for use in DAZ Studio. I'm using Blender to create the model, but I'm sure my problem isn't specific to Blender. The result is that the cliff looks good in Blender, but when I bring it into DAZ Studio and render with Iray, shadows in the shape of triangles appear scattered across the object's surface. These are the same triangles I've seen before that can pop out of the shadows cast on Genesis 2 characters when they are rendered in Iray.

If you are familiar with the triangles I'm talking about and know how to combat them, will you please tell me?

WendyLuvsCatz

Smoothing modifier and add subdivision (just for render)

Padone

Unfortunately this is a common issue in any PBR engine. If you render with cycles you'll get the same. It's called the shadow terminator effect and it's most visible when you have harsh lights and a low poly object. The solution is either to soften the lights and/or increase the polycount as th3Digit is advising.

http://blog.irayrender.com/post/29042276644/shadow-acne-and-the-shadow-terminator

Inkubo

I'll try some of these solutions, including removing my normal map as the article suggests.

Inkubo

I have rendered an image with my object loaded, along with a character so you can tell you're not looking at an extreme closeup. There are no maps applied, so you're not seeing the effect of any bump, normal, or displacement map. Resolution Level: Base is the only setting available in the Mesh Resolution parameters, so as far as I can tell I can't change the smoothing or level of subdivision.

I suspect the unwanted terminators are caused by triangulation of quads where the four vertices don't all lie along the same plane. But how can I sculpt so as to make a mesh that doesn't have this problem?

WendyLuvsCatz

under edit, object, add smoothing modifier and set subdivision

Inkubo

Thanks, @th3Digit! Edit > Object > Geometry > Convert to SubD totally worked!

Padone

Also, if you use displacement instead of normal maps, you will find a subd level there. This has the advantage that doesn't smooth so it's faster. Also, for HD characters you'll be forced to crank-up subd anyway so you also avoid terminators and you catch two for one.

Personally, for performance reasons, I stay away from HD and high-subd and I rather work with normal maps and low-subd. Then I try to adjust the light softness to avoid terminators. But if I'm forced then I pass to displacement, such as for extreme closeups.

 

EDIT: A simple trick is to add a flat displacement map so you can use the fast subd there for terminators. Of course you will also need a basic catmark subd for deformations.

EDIT: Another interesting thing you can do is to export HD to obj and bake it to maps with Blender.

https://www.youtube.com/watch?v=_0FwsMkWm0k

Inkubo

I don't buy the HD add-ons. The only HD character I really use is the Minotaur 6, and as you could see in the link in my original post, it's plagued with terminators.

When you say "flat displacement map," you mean a bitmap filled with one shade of neutral gray so there's no actual displacment, right?

Padone

yes, 128 rgb will do

Inkubo

Thank you!