Jagged edges in IRAY renders (DS 4.15)

denisnormandin

I have seen proposed solutions for this in the forum, but they were for previous versions of Daz Studio... and they don't work.

I have made many good renders with Iray so far and I had never encountered this problem before.

In the attached image you can see obvious jagged edges on rounded objects but not on the rest of the scene.

The outline of the four closest balls are not round as they should, and more obviously in the gradient shades of the yellow ball and cue ball.

Also on the left arm's sleeve.

But I noticed afterwards that it is not only in the Iray render, even in the viewport, with Filament displayed, the problem is visible (though less obviously).

Is there some tweeking I can do to resolve this problem?

ebergerly

Have you tried converting the geometry to SubD? And also in the Surfaces tab for each surface with the problem, under Geometry did you check all the smoothing stuff is applied? 

denisnormandin

ebergerly said:

Have you tried converting the geometry to SubD? And also in the Surfaces tab for each surface with the problem, under Geometry did you check all the smoothing stuff is applied? 

I don't know what SubD is or how to do such a conversion.

For the smoothing stuff you are mentioning, if it is "Smooth" (on), "Angle" (89.9), "Round corners radius" (0), "Round corners across materials" (on), "Round corners roughness" (1)...

Yes I have tried tweeking those but only pushing the "Angle" value to its maximum (180) ad a slight effect on the balls. Doing the same on the sleeves had no visible effect.

ebergerly

The first image below is the Wire Shaded preview of a simple, low poly sphere. I assume the balls in your image are similar. The challenge is that it's tough to convert a low polygon mesh like this into a nice smooth shape in the actual render. The second image shows a worst case Iray render, with harsh lighting and just the right view angle. 

SubD is used extensively in 3D, and it basically subdivides the mesh into many polygons, but also has some logic that makes those new polygons oriented in a much smoother shape. The third image is an Iray render of the same sphere with SubD applied.

To apply it, just select the object and in the top right corner of the Scene view is a tiny icon with an arrow and some straight lines. Select that, and in the dropdown select Edit/Geometry/Convert to SubD. You can also tweak the SubD values under Parameters/Mesh Resolution.

denisnormandin

Thanks for that, I tried it and did just a spot render on the cue ball. I did no tweeking in the parameters and it produced much better results, unfortunately the spot render alone took close to two houres! and had speckeled lighting artifacts.

I'm gonna try a full render but I'm afraid that this could take much longer.

As for the sleeve of the dress: I get an error message "You must select an object in the scene that contains geometry..." So no luck there.

ebergerly

Hmmm...not sure how a SubD'd sphere or two could affect render times a lot. Below is an interior render where I placed a big low poly sphere in the center and did an Iray render. Total render time was 7 minutes and 7 seconds. I then applied SubD to the sphere and hit render, and it rendered in virtually the same time, 7 minutes and 13 seconds. 

Perhaps there's something else going on that would affect the render time and quality. 

ebergerly

By the way, I did a spot render on this image around the sphere and it only took about 30 seconds. 

Regarding the dress, I think you need to select the entire dress, not just the sleeve. 

Spacious

It sounds like maybe you subdivided more that just the pool balls.  If you subdivided the whole room or even the whole pool table it would substantially increase how long it would take to render.

On a side note I've been noticing these kinds of visual artifacts much more with the version of iray that's in DAZ 4.15 than I've seen before.  I don't think it's DAZ's fault, and that it's got to do with the iray version that's included.  Hopefully it'll get sorted out eventually so that these things become more rare again.

denisnormandin

I always have long render times, but the difference was considerable anyway.

I selected only the cue ball, the number one (yellow solid), the number 14 (green striped) and number 11 (red striped), one by one applying the SubD only once for each and didn't tweek the settings.

Now I have made a complete render and the jaggedness has gone, but there is a lot of noise all over, like the render had quit befor the end.

I don't know how long it took since I started the render when I was leaving for work.

ebergerly

I noticed you have Firefly Filter disabled. You might want to enable that. Sounds like you have some issues with your render settings. 

denisnormandin

Thanks again,

I must have turned that off by mistake at one point.

I did a new render, it's much better, it took probably close to two houres (1:45 at 86% done the last I checked).

So thanks for everything, now I will choose another dress to avoid the jagged effect on the sleve of that one and probably change the HDRI (I don't like how it looks through the windows) and experiment on a few poses.

This is all for learning purposes anyway.

Anim

Regarding the dress. The message "You must select an object in the scene that contains geometry..." often means that the object has the subd modifier already applied. You can check this in:

Parameters - General - Mesh Resolution

If you can switch it from "Base" to "High Resolution" then it is in subd mode.

In High Resolution there are two relevant sliders.

View SubD Level = SubD level in the viewport including iray mode

Render SubD Level = SubD level in the final render (DS sets this one level above View SubD Level but you can reduce it by hand if required)

If the dress is already in SubD try to increase View SubD level to check if it helps. If it does then set the Render SubD the same or even higher if not done automatically by DS already.

Mr_ E

Does anyone have a suggestion to improve my settings when all items within my render look jagged?