Have you tried adjusting the texture or displacement strength any?

It could also be that is a tileable material because the image you posted is 512x512 pixels and an image that small would need to be tiled on a floor or ground prop of any size. Unless you reduced that image for the forums then ignore this last part.

Here's a more side-on render with the displacement set to 0.1 as before (left) and 0.03 (right). So the circles are definitely displacement. And when it's reduced to zero they vanish completely.

I guess the answer is that it's a side-effect of using such a tiny image!

Glad you figured it out

displacement is measured in your local units, as set in your Preferences. So when that's meters, then 0.1 = 10cm which might be quite a lot.

What is your unit of measure?

I use Poser units*, so 0.1 displacement would be nearly ten inches! Yes, I'm a bump/displacement lover - I find the standard 0.009 values too small for my tastes, so I usually crank up bump/displacement to a ridiculous 0.1 or 0.01 initially, and then reduce it a bit. My ladies don't like me doing that with their skin textures!  ;o)

*Why? Although most values are shown in your selected units, some values are always shown in Poser units (e.g. displacement bounds iirc? I find the inconsistency annoying, and I can never remember which ones). And I'm fairly sure that all values stored in Poser files are in Poser units. So I stick to Poser units

     You might also experiment with setting the texture filtering (on the image map node) to none.

None/Fast look the same (no circles), and Quality/Crisp look the same (the circles appear).

Although most values are shown in your selected units, some values are always shown in Poser units (e.g. displacement bounds iirc?

Wrong. Some vales are consistently in mm (scatter depth), some in cm, grams, seconds or related (cloth and hair rooms), and anything related to bump/displacement is in the units you specified in Preferences. That's in the manual.

I find the inconsistency annoying, and I can never remember which ones.*

I'm with you. But the ones that change value when I alter my prefs, are the ones in my prefered units. I've sorted them all out :-(*

And I'm fairly sure that all values stored in Poser files are in Poser units

Wrong, material room is stored in inches, that's why Bagginsbill works in those. And the ones with stick with their own units and do not relate to your prefs, are stored just the way they come.

Sorry for this.*

But you're signature line says "Usually I'm wrong" - so should I believe your post, or your signature line?  ;o)

Yep, I knew it was something like that. More or less. It's just that I got the details a bit mixed up... okay, a lot mixed up... okay, 'wrong'... :o)

Cheers, Pete

 

*In truth I think I see all Poser numbers as just being numbers, with no units. So, for example, 0.00956 just doesn't have the right degree of 'displacementbigness' to be a good value for displacement in my view....  :oS  
*

*Yep, it's a miracle that I ever get anything to work!*

hi Pete :-)

well, some numbers have units, and can be compared with / converted from reallife measurements and tables in physics books. Of course, using them might make your objects more realistic, but that doesn't imply that your images become more satisfying.

As the special FX people in action movie can tell, the behavior of objects and materials should not be more real, but more believable which in some cases is something entire different (no, car's don't explode when they fall from a bridge, and granades hardly produce fire). So, your artistic requirements come first.

Whether my posts are right, or my signature is: at least my intentions are right, and you'd better check out the details yourself anyway. And not just mine :-) 

The displacement settings seem to work ... I've had the same pattern show up as black shadows in old "sets" and environmental props.

Glad I'm not the only one who's seen it!

I think the answer to the original question "Where are the circles coming from?" is that it's a combination of the following three things:

• Displacement: only occurs with non-zero displacement (and displacement enabled in rednder settings of course!)

• 'Filtering' setting in the Image_Map node: only seems to occur with 'Quality' or 'Crisp' settings

• Very small texture images: I'd guess that the circle size (and maybe the amount of displacement too?) is related to the dimensions of a single pixel from the texture image after mapping onto the surface?

Pete

P.S. aRtBee - I love your signature line "Usually I'm wrong. But to be effective and efficient, I don't need to be correct or accurate.". Very wise! I wish I'd thought of it first! ;o)

It all makes sense and it's nice after several years of dealing with this to have it explained so nicely.  I always called it the Pointseta effect, because it looked like plant leaves to me.  :)

Pointsettia.

LOL.  I know it was wrong ... but I was in a hurry.  thanks.  ;)

Welcome.

The most bizarre thing is that I hadn't seen the effect for ages. But I recently created a scene using a building from DexSoft Games desert oasis and the effect appeared. And then I noticed the pattern on the building (above right)...

And then it appeared over on the DAZ homepage too (above left)...

spooky!