White Specks on Shiny Surfaces

[Natron]

I'm doing some test renders for a project I'm working on, and I'm getting very strange white specs on all of my reflective surfaces. Not just metallics and glass, but on walls with glossy paint, or on the wood. No matter which render setting I use from 01-08, these specks appear. If I reset the texture, they go away, but then everything looks odd and flat, of course. I've attached a rendering using medium +, and you can see that the white bits are extremely distracting.

Any ideas what's causing this?

[Chris]

Your render did not get attached.

[Natron]

Ah, sorry. Turns out it was too big and I didn't notice. Here is a slightly cropped version.

[Fletch]

Do they remain if you render with Easy 09? Avoid using Easy 08 for any scene other than daylight exteriors.
I would think from this view that it's a problem with the light objects.
Make the radius for any point or spot light small, like 0.01
Be sure if rendering with easy 1-7 to avoid Light Emitting Surface materials = aka area lights or aka light emitters or aka LEMs - these can also cause artifacts and greatly slow render times.

If all the lights are done according to my tips above and problem persists, then it's a material or AA = anti-aliasing issue. The material issue, we would need to see the scene to help you with. The AA issue, you can try the extra AA settings in the Settings folder when you choose a render setting.

If problem persists, licensed users may send stripped-down scenes in email that exhibit the problem behavior to "support at twilightrender dot com"

[Natron]

Hey, thanks for getting back to me so quickly.

I tried to render with Easy 09 and the speckles do go away. I only rendered 7 passes, but it's enough to tell what's going on. I also tried making my spot lights smaller, but it just made the scallops on the walls much more pronounced and a bit ugly. Changing my pot lights to point instead of spot lights makes it much brighter, but the renders take forever.

The renders will look fine with easy 09 or easy 10, but the problem is that this is going to be an animation, so I'm trying to squeeze the render time down to something acceptable while not killing my quality completely. The problem is less pronounced when I use Medium AA(Ultra), which I've attached, but that one only got to 65% of the anti-aliasing step in 3.5 hours. I've been trying to create a low setting with an ultra fine AA, to decrease my render time. I've started with low(Ultra AA), which gets my render time to 15 minutes/frame at 1080p, but those white specks will be a distraction in the final render. I think what I'll try to do is make a small animation tonight using a custom setting based on Medium with Ultra AA, shooting less photons and having a much smaller final gather ray number. Hopefully that will help out. I'll let you know how it goes.

[Fletch]

Fly thru animation at 1080p will require very long render times if you apply specular (plastic for instance) to a lot of your surfaces. For the animation, for the sake of render times, I suggest making as many of your surfaces as possible to be flat, or if you have a good render farm, you may be ok.

[Natron]

Well, if that's the case I may also resort to doing some render baking to get the walls to look good. Rounding the edges off will also help quite a bit, so I'll just try that out as well and leave the paint flat.

I'll be using the Amazon EC2 service to render it all, so it shouldn't be TOO horrible in terms of render time. I'll let you know how it all goes.

Thanks for your help!

[Fletch]

1. render to amazon cloud ~using Kerkythea
2. Rick's experience with the Amazon Cloud~using Kerkythea

[millermafia]

I have an exterior rendering that I am getting similar issues with. I am using Easy 08 and I am getting multicolored specs around my reflective surfaces. It doesnt matter how many passes I make the specs do not go away.

[Fletch]

I've seen this happen with HDR sky when rendering with Easy 08 render setting. It also happens if you are using NK metals material library, or some of the car paints, these metals don't always render well with this render setting. Try Easy 09, it should solve the issue.