OTOY Forums

Hello,

I seem to be having this strange thing happen with flat surfaces. The material has concentric ring patters (think Saturn's rings with Saturn in the middle). It also has triangles. This happens with Daz materials and LiveDB materials.

This does not seem to be a material problem as 1) that patterns change whenever I move the camera (?!?). That is the ONLY change...a slight movement of the camera. Also, 2) this does not happen when the .obj is imported into Octane Render using the same materials.

Assistance would be appreciated.


Thank You

JM

If you are using a camera preset, copy it so that the ray epsilon value can be automatically recalculated or manually adjusted. There are some threads covering this issue, and this specific fix was recommended (and worked) in one of the threads here (by me). If you aren't using a preset, adjust the value manually, and search the main forum for recommended values. A search for "epsilon" should get you to some of the relevant posts.

I get this as well, much more so under OcDS 2.x, I'm assuming it's because ray epsilon defaults to automatic in the preferences now and gets it wrong, whereas I never touched the setting and left it as default under 1.2. Guess I'll be turning that off now

By the way, is it distance based? As it always seemed to go away if I moved the camera closer to the affected area and I can always reproduce it if I make a flat plane (bigger seems to make it worse) in DS and turn it face on to the camera and then move it large distance away (which I sometimes do as a background).

its the rayepsilon. adjust it to fix it

probably your scene is really big, or really small.

SiliconAya wrote:By the way, is it distance based? As it always seemed to go away if I moved the camera closer to the affected area and I can always reproduce it if I make a flat plane (bigger seems to make it worse) in DS and turn it face on to the camera and then move it large distance away (which I sometimes do as a background).

Yes.

From the standalone manual:

Ray Epsilon (rayepsilon)
The ray epsilon is the distance to offset new rays so they don’t intersect with the originating geometry. If the scale of your scene is too large, precision artifacts in the form of concentric circles may appear. In that case, increasing the ray epsilon can make these artifacts disappear.

Also, as far as I know, the auto value has always been present (it's a checkbox on the preferences tab). It becomes nullified when a preset render setting is used, as a preset locks all values, including this, so it can't be recalculated. This means it would never be an issue, as long as your relative scene size is pretty close to the same as the one used when the preset was saved. Hence why the easiest fix if using a preset is just to copy it, since all settings are the same, but unlocked so that this value can recalculate, though it may require a slight movement of the camera to force the recalculation (I usually just scroll the mouse-wheel back once then forward once again, and it clears up, works for forcing an auto-refocus most often as well, if that was also locked in a bad spot). This will usually fix it, and makes it adjustable if needed. I'm not sure how it's calculated (as in whether it's off a fixed focal distance or an average of parts of the scene, but yes, generally large surfaces and very specific geometry are most prone to having the rings appear.

the ray epsilon value is locked for me no matter what i do I tried copying the camera and that didn't work. I did make a new camera and it did calculate a new value, but it is still locked.

The ray epsilon is locked by the render setting. Creating a new camera may force a new calculation, but to unlock it, you need to not be in a preset render setting. The render setting applies to all cameras in scene, so if it's locked into a preset, that lock applies to all cameras, since it's a lock within the rendering kernel itself. It would be neat if each camera could have it's own render setting independently, but I presume that would make things even more complicated behind the scenes.

Edit: In addition, this is a new one, but apparently, if "Automatic calculation of kernel 'rayepsilon'" value is checked under preferences, you can't adjust it manually, whereas you still could in 1.2. May require toggling back to a different render setting then re-selecting your preferred one to unlock after clearing the check box. Not sure if that qualifies as a new bug or an old one that was corrected to the current behavior.

sikotik13 wrote:
Edit: In addition, this is a new one, but apparently, if "Automatic calculation of kernel 'rayepsilon'" value is checked under preferences, you can't adjust it manually, whereas you still could in 1.2. May require toggling back to a different render setting then re-selecting your preferred one to unlock after clearing the check box. Not sure if that qualifies as a new bug or an old one that was corrected to the current behavior.

Ah I'll pay attention to that going forward. Thanks much.

No problem. Always good to find stuff that has changed before I need it